CT and MRI findings of acute calculous cholecystitis and its complications in Singapore: A pictorial review.

INTRODUCTION: Acute cholecystitis (AC) is a common problem encountered in surgical practice. This occurs due to obstruction of the cystic duct by calculi resulting in inflammation of the gallbladder. Increasingly, contrast enhanced computed tomography (CECT) and Magnetic Resonance Imaging (MRI) scans are being used for assessment. While the imaging features of AC are well recognized and extensively described in the literature, radiological features of the rarer complications related to AC such as pseudoaneurysm formation and gallbladder volvulus are less well known. We aim to describe these rarer findings in our pictorial review, to better educate the clinician and radiologist, such that timely diagnoses can be reached, and relevant management can be affected. METHODS: A collection of cases showing the common acute gallbladder pathologies and complications such as acute cholecystitis, gangrenous cholecystitis, emphysematous cholecystitis, haemorrhagic cholecystitis, Mirizzi's syndrome, gallbladder perforation and abscess formation, were collected between July 2016 and March 2018 at two different medical institutions in Singapore. In addition, rarer cases of gallbladder volvulus and vascular complications such as cystic artery pseudoaneurysms and vessel erosions, were also followed up. RESULTS: The CT and MRI imaging features of these conditions were discussed, with key diagnostic imaging features emphasized. CONCLUSION: Acute gallbladder pathologies are commonly encountered in day-to-day radiology practice. Knowledge of the rarer gallbladder pathologies and their key imaging features will help the radiologist, in particular, the on call radiologist in training, improve diagnostic accuracy and allow for timely management.

L-arginine promotes gut hormone release and reduces food intake in rodents.

AIMS: To investigate the anorectic effect of L-arginine (L-Arg) in rodents. METHODS: We investigated the effects of L-Arg on food intake, and the role of the anorectic gut hormones glucagon-like peptide-1 (GLP-1) and peptide YY (PYY), the G-protein-coupled receptor family C group 6 member A (GPRC6A) and the vagus nerve in mediating these effects in rodents. RESULTS: Oral gavage of L-Arg reduced food intake in rodents, and chronically reduced cumulative food intake in diet-induced obese mice. Lack of the GPRC6A in mice and subdiaphragmatic vagal deafferentation in rats did not influence these anorectic effects. L-Arg stimulated GLP-1 and PYY release in vitro and in vivo. Pharmacological blockade of GLP-1 and PYY receptors did not influence the anorectic effect of L-Arg. L-Arg-mediated PYY release modulated net ion transport across the gut mucosa. Intracerebroventricular (i.c.v.) and intraperitoneal (i.p.) administration of L-Arg suppressed food intake in rats. CONCLUSIONS: L-Arg reduced food intake and stimulated gut hormone release in rodents. The anorectic effect of L-Arg is unlikely to be mediated by GLP-1 and PYY, does not require GPRC6A signalling and is not mediated via the vagus. I.c.v. and i.p. administration of L-Arg suppressed food intake in rats, suggesting that L-Arg may act on the brain to influence food intake. Further work is required to determine the mechanisms by which L-Arg suppresses food intake and its utility in the treatment of obesity.

Dialysis disequilibrium syndrome: A preventable fatal acute complication.

Dialysis disequilibrium syndrome (DDS) is a neurological disorder with varying severity that is postulated to be associated with cerebral oedema. We described a case of DDS resulting in irreversible brain injury and death following acute haemodialysis. A 13-year-old male with no past medical history and weighing 30kg, presented to hospital with severe urosepsis complicated by acute kidney injury (Creatinine 1422mmol/L; Urea 74.2mmol/L, Potassium 6.3mmol/L, Sodium 137mmol/L) and severe metabolic acidosis (pH 6.99, HC03 1.7mmol/L). Chest radiograph was normal. Elective intubation was done for respiratory distress. Acute haemodialysis performed due to refractory metabolic acidosis. Following haemodialysis, he became hypotensive which required inotropes. His Riker's score was low with absence of brainstem reflexes after withholding sedation. CT Brain showed generalised cerebral oedema consistent with global hypoxic changes involving the brainstem. The symptoms of DDS are caused by water movement into the brain causing cerebral oedema. Two theories have been proposed: reverse osmotic shift induced by urea removal and a fall in cerebral intracellular pH. Prevention is the key to the management of DDS. It is important to identify high risk patients and haemodialysis with reduced dialysis efficacy and gradual urea reduction is recommended. Patients who are vulnerable to DDS should be monitored closely. Low efficiency haemodialysis is recommended. Acute peritoneal dialysis might be an alternative option, but further studies are needed.

Characteristic corrosion resistance of nanocrystalline TiN films prepared by high density plasma reactive magnetron sputtering.

Nanocytalline TiN films were deposited on non-alkali glass and Al substrates by reactive DC magnetron sputtering (DCMS) with an electromagnetic field system (EMF). The microstructure and corrosion resistance of the TiN-coated Al substrates were estimated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical methods. All the TiN films shows that they have a (111) preferred orientation at room temperature. TiN films deposited on Al substrate using only DCMS 400 W showed a sheet resistance of 3.22 x 10-1 omega/symbol see texts (resistivity, 3.22 x 10-5 omegacm). On the other hand, a relatively low sheet resistance of 1.91 x 10-1 omega/symbol see text (1.91 x 10-5 omegacm) was obtained for the dense nanocrystalline TiN film deposited on Al substrate using DCMS 375 W+ EMF 25 W, indicating that the introduction of an EMF system enhanced the electrical properties of the TiN film. TiN films deposited on Al substrate at 400 degreesC had a (200) preferred orientation with the lowest sheet resistance of 1.28x10-1 omega/symbol see texts (1.28 x 10-5 omegacm) which was attributed to reduced nano size defects and an improvement of the crystallinity. Potentiostatic and Potentiodynamic tests with a TiN-coated Al showed good corrosion resistance (l/corr, = 2.03 microA/cm2, Ecorr = -348 mV) compared to the uncoated Al substrate (/corr = 4.45 microA/cm2, Ecorr = -650 mV). Furthermore, EMF system showed that corrosion resistance of the TiN film also was enhanced compared to DCMS only. For the TiN film deposited on Al substrate at 400 degreesC, corrosion current and potential was 0.63 micro/cm2 and -1.5 mV, respectively. This improved corrosion resistance of the TiN film could be attributed to the densification of the film caused by enhancement of nitrification with increasing high reactive nitrogen radicals.

Guidelines for management of androgenetic alopecia based on BASP classification--the Asian Consensus Committee guideline.

BACKGROUND: Androgenetic alopecia (AGA), or pattern hair loss, is a common disorder in both Asian men and women. There are several guidelines for the treatment of AGA which are suitable for Caucasian patients; however, each of these has some limitations. Furthermore, in comparison with Caucasian patients, Asian patients with AGA have different types of hair loss and family histories which may alter the treatment response. There is currently no published AGA guideline for Asian patients. OBJECTIVES: The Asian Consensus Committee for Androgenetic Alopecia aimed to develop an algorithmic guideline, based on the basic and specific (BASP) classification, for the treatment of AGA especially in Asian patients. METHODS: The committee collaborated extensively on reviewing available literature on AGA treatment in order to formulate an algorithmic guideline on AGA management. RESULTS: Previously published guidelines based on pre-existing classifications of AGA cannot easily classify the patterns of AGA that are more frequently seen in Asians. The BASP classification not only facilitates the development of a unified and simplified algorithm, but also overcomes the disadvantages of previously reported classification systems. CONCLUSIONS: The proposed treatment guideline for AGA based on the BASP classification may be useful for dermatologists in their approach to treating Asian patients with AGA in clinical practice. Ideally, clinicians should try to utilize this guideline consistently in their practice to monitor treatment response with the goal of enhancing successful outcomes. This will help boost patients' confidence and self-esteem, thus improving patient' compliance with the prescribed treatments.

Molecular dynamics simulation of ZnO nanowires: size effects, defects, and super ductility.

Molecular dynamics simulations of ZnO nanowires under tensile loading were performed and compared with simulations of TiO(2) wires to present size-dependent mechanical properties and super ductility of metal oxide wires. It is shown that while large surface-to-volume ratio is responsible for their size effects, ZnO and TiO(2) wires displayed opposite trends. Although the stiffness of both wires converged monotonically to their bulk stiffness values as diameter increases, bulk stiffness represented the upper bound for ZnO nanowires as opposed to the lower bound for TiO(2) wires. ZnO nanowires relaxed to either completely amorphous or completely crystalline states depending on wire thickness, whereas a thin amorphous shell is always present in TiO(2) nanowires. It was also found that when crystalline ZnO nanowires are stretched, necking initiated at localized amorphous regions to eventually form single-atom chains which can sustain strains above 100%. Such large elongations are not observed in TiO(2) nanowires. Using the analogy of a clothesline, an explanation is offered for the necessary conditions leading to super ductility.

Hand-assisted laparoscopic abdomino-perineal resection utilizing the planned end colostomy site.

BACKGROUND: Aim of the study was to determine the feasibility and outcomes of utilizing the planned end colostomy site for placing the hand-assist device in performing hand-assisted laparoscopic abdominoperineal resections (HAL APR) in patients with low rectal cancer. METHODS: Patients with low rectal cancers not suitable for a sphincter salvage proctectomy were recruited. HAL APR was performed by placing the hand-assist device over the planned colostomy site. Standard total mesorectal excision (TME) was performed, and the specimen was delivered via the perineal incision. Patient data and perioperative variables were obtained from the institution colorectal cancer database and analyzed. RESULTS: Six patients underwent HAL APR from November 2004 to January 2006. Mean operative time was 213 min with no conversions or intraoperative complications. One patient developed post-operative ileus which resolved spontaneously. There were no other morbidities or mortalities. Mean hospitalization was 6.8 days. After a mean follow-up of 13.3 months, one patient developed a parastomal hernia which was subsequently repaired during liver resection for liver metastases. No other long-term complications occurred. CONCLUSION: HAL APR with the hand device placed at the planned stoma site is technically feasible. Without creating an additional incision, the operation is oncologically comparable and renders similar short-term outcomes as SL methods, maintaining the benefits of a minimally invasive approach.

Hand-assisted laparoscopic colectomy versus standard laparoscopic colectomy: a cost analysis.

OBJECTIVE: There is a relative dearth of literature comparing hand-assisted (HALC) to standard (SLC) laparoscopic colectomies. HALC seems beneficial in terms of shorter operative times and lower conversion rates, but this is counterbalanced by a greater inflammatory response, larger incisions and higher direct costs. Nevertheless, these results are not consistent throughout existing studies and there are to date no detailed cost comparisons. Our hypothesis was that HALC would not incur significantly higher institutional costs compared with standard laparoscopic techniques. METHOD: Patients undergoing either SLC or HALC between August 2004 and September 2006 were retrospectively reviewed. All patients were managed using a standard protocol. Outcomes assessed included operative times, conversion rates, pain scores, time to resolution of ileus, length of stay and complications. Total costs were calculated from the day of surgery. Statistical analyses included chi(2), Fisher's exact test, the Mann-Whitney U-test or nonparametric bootstrapping method. RESULTS: Seventy-three patients underwent SLC while 101 had HALC. Demographics and indications for surgery in both groups were similar; the majority were performed for colorectal cancers. Operative times were shorter (147.5 vs 172.5 min, P < 0.05) and complication rates lower (28.7%vs 45.2%, P < 0.025) for HALC. There was no significant difference in the other clinical outcomes. Operative costs and cost of consumables were higher for HALC (US$4024.2 vs US$3568.1, P = 0.01 and US$1724.7 vs US$1302.7, P < 0.001, respectively). However, total costs were not significantly different (HALC US$8999.8, SLC US$7910.7, P = 0.11). CONCLUSION: Institutional costs are not significantly higher for HALC compared with SLC.

An evaluation of the value of group education in recently diagnosed diabetes mellitus.

Diabetic patients have a 12% to 25% lifetime risk of developing foot complications leading to significant morbidity and mortality. The objective of this study was to assess the effectiveness of group education in improving patient awareness of foot care. The authors evaluated the effect of group size and areas in which knowledge seemed to be most affected. Patients attending a 2-hour teaching session between November 2005 and March 2006 were recruited. Patients filled in an 18-part questionnaire before and after the teaching session to assess knowledge. Fifty-nine patients recently diagnosed with diabetes mellitus or foot complications were recruited for 7 sessions. Analysis of the data showed a statistically significant improvement in foot care knowledge after the teaching session compared with before (69% to 85%, P < .001). Patients in the smaller group (n < 10) had significantly higher scores compared with the bigger groups (n > 10; P < .025). These data show the benefit of group education about foot care for patients with diabetes. Smaller groups benefited more than larger ones did, which could be attributed to the sizes allowing for better interaction between the tutor and patient. As patient knowledge is variable from individual to individual, smaller teaching sessions may allow patients to address specific concerns.

Photoangioplasty: An emerging clinical cardiovascular role for photodynamic therapy.

Photodynamic therapy (PDT) has been studied and applied to various disease processes. The potential of PDT for selective destruction of target tissues is especially appealing in cardiovascular disease, in which other existing interventional tools are somewhat nonselective and carry substantial risk of damage to the normal arterial wall. Enthusiasm for photoangioplasty (PDT of vascular de novo atherosclerotic and, potentially, restenotic lesions) is fueled by more effective second-generation photosensitizers and technological advances in endovascular light delivery. This excitement revolves around at least 4 significant attributes of light-activated therapy: the putative selectivity and safety of photoangioplasty, the potential for atraumatic and effective debulking of atheromatous plaque through a biological mechanism, the postulated capability to reduce or inhibit restenosis, and the potential to treat long segments of abnormal vessel by simply using fibers with longer light-emitting regions. The available nonclinical data, coupled with the observations of a new phase I trial in human peripheral atherosclerosis, suggest a promising future for photoangioplasty in the treatment of primary atherosclerosis and prevention of restenosis.

Noninvasive functional imaging of human brain using light.

Analysis of photon transit time for low-power light passing into the head, and through both skull and brain, of human subjects allowed for tomographic imaging of cerebral hemoglobin oxygenation based on photon diffusion theory. In healthy adults, imaging of changes in hemoglobin saturation during hand movement revealed focal, contralateral increases in motor cortex oxygenation with spatial agreement to activation maps determined by functional magnetic resonance imaging; in ill neonates, imaging of hemoglobin saturation revealed focal regions of low oxygenation after acute stroke, with spatial overlap to injury location determined by computed tomography scan. Because such slow optical changes occur over seconds and co-localize with magnetic resonance imaging vascular signals whereas fast activation-related optical changes occur over milliseconds and co-localize with EEG electrical signals, optical methods offer a single modality for exploring the spatio-temporal relationship between electrical and vascular responses in the brain in vivo, as well as for mapping cortical activation and oxygenation at the bedside in real-time for clinical monitoring.

High sensitive SiO2/TiO2 hybrid sol-gel material for fabrication of 3 dimensional continuous surface relief diffractive optical elements by electron-beam lithography.

A negative-tone sensitive SiO2/TiO2 organic-inorganic hybrid sol-gel material was synthesized and characterized for fabrication of multilevel micro-optical elements by direct electron-beam lithography. The exposure was carried out by an in-house modified electron-beam writing system using LEO SEM-982 with Elphy Quantum exposure beam-blanking control system at 25keV. The hybrid Sol-Gel material demonstrated a superb sensitivity for doses between 0.22microC/cm2 and 0.33microC/cm2.

Cost-effective fabrication of microlenses on hybrid sol-gel glass with a high-energy beam-sensitive gray-scale mask.

A negative-tone inorganic-organic hybrid SiO(2):TiO(2) glass is investigated for fabrication of refractive microlenses. This sol-gel material enjoys an advantage over materials used in conventional photoresist-based fabrication techniques in that it lends itself to a single-step etching-free process. The application of a high-energy beam-sensitive (HEBS) mask provides a reliable and simple method for fabrication of three-dimensional micro-optical elements with a single UV exposure. The technique of using the sol-gel material with the HEBS gray-scale mask has considerable potential for low-cost mass production of continuous-phase-level diffractive optical elements and micro-optical structures.

Optimized polarization-selective computer-generated hologram with fewer phase combinations.

Normally, to incorporate two binary conventional computer-generated holograms (CGHs) into a single polarization-selective computer-generated hologram (PSCGH), the respective pixels of the conventional CGHs will result in 4 different combinations of the phase values. Thus, the 4 phase combinations have to be realized by 4 types of pixel structures in a PSCGH. In this paper, we propose a method to reduce the PSCGH's 4 phase combinations to 3 using an optimization approach. The PSCGH's first-order diffraction efficiency is 30% and the contrast ratio is 28 after the optimization.

Single-step fabrication of continuous surface relief micro-optical elements in hybrid sol-gel glass by laser direct writing.

A negative tone hybrid sol-gel material was applied to the fabrication of continuous surface relief micro-optical elements by laser direct writing lithography. The hybrid sol-gel glass was synthesized as UV photosensitive material and used for the fabrication of micro-optical elements with continuous surface relief profile. The surface profile was directly controlled by the UV exposure dosage and the exposed areas were crosslinked and converted into sol-gel glass with relief structures. The UV exposure dosage was realized by an acousto-optic modulator (AOM) in the laser direct writing system. Characterization results indicated that the thickness of the sol-gel glass has a linear response to the AOM values ranging from 3.25 to 5.5. The sol-gel thin film was measured to have a refractive index of 1.52 and the maximum thickness of 2 microm. For various designs of diffractive optical elements within the visible wavelength, the sol-gel film enables us to achieve an arbitrary phase change between 0 and 2 pi with the linear AOM exposure range. As an example, a blazed grating with a period of 45 microm and height of 1.17 microm was fabricated in the sol-gel glass using direct laser writing method.

Triatomines as experimental vectors of trypanosomes of Asian monkeys.

Systematic surveys of the wild macaques of South Asia by blood culture resulted in the discovery that trypanosomiasis is enzootic in the simians of Indonesia, Malaysia, India, and Thailand. The isolates obtained differ in morphology, metabolism, and ability to multiply in arthropods. Following this discovery, interest focused on possible transmissions of these trypanosomiases. Laboratory-reared and wild-caught insects were studied to determine which are satisfactory intermediate hosts and potential natural vectors. Successful results were obtained with insectary-reared reduviids and Indonesian isolates. In Rhodnius prolixus and Triatoma rubrofasciata the Indonesian trypanosomes multiply for periods which can exceed 40 days. The flagellate infections are in the digestive tract, whereas trypanosomes have never been seen in the salivary glands or in the hemolymph. The feces of trypanosome-carrying reduviids are infective, suggesting a stercoreal method of infection of mammals, and infection was produced in experiments in which feeding by the insects was not possible. The relevance of these findings to natural transmission in Indonesia is not known. Experiments with insects and all other trypanosomal isolates have been negative. The natural transmission mechanism(s) of the simian trypanosomiases in South Asia remains an unsolved problem.

Identification of Brugia malayi in vectors with a species-specific DNA probe.

We evaluated the potential value of a cloned sequence of genomic DNA of Brugia malayi as a species-specific probe. Clone pBm 15 reacted with all stages of 8 different geographic isolates of B. malayi and cross-hybridized with microfilariae of B. timori. It did not hybridize with Wuchereria bancrofti or with B. pahangi, W. kalimantani, Dirofilaria repens, Breinlia booliati or Cardiofilaria species, animal filariids that can be sympatric with B. malayi. P32-labeled clone pBm 15 correctly identified mosquitoes infected even with 1 infective larva of B. malayi. This specific DNA probe should be an invaluable tool to monitor control programs of Brugian filariasis.

Laser balloon angioplasty.

Unlike conventional transluminal percutaneous angioplasty (PTCA), which applies only intraluminal pressure, laser balloon angioplasty (LBA) employs simultaneous heat and pressure to reopen heavily occluded arterial lumens. The circumferential irradiation of Nd:YAG (1.06 microns) laser light is directly absorbed by approximately 1 to 2 mm of arterial tissue immediately adjacent to the inflated balloon. Such heating by LBA is able to seal disrupted luminal flaps, thermally remodel the luminal surface topology, reduce arterial recoil, selectively (partially) dehydrate thrombus, and possibly even reduce thrombogenicity at atherosclerotic sites. Criteria for successful LBA are defined based on earlier fundamental in vitro experiments to determine effective welding temperature, laser power doses, and exposure period; in addition, the derivation and validity of a three-part optical-thermal model and its application in parametric dosimetry analysis are presented. Though the lumen remodeled by LBA is acutely satisfactory, recurrence of the lesion is problematic chronically. Because of this, LBA is currently most useful as an adjunctive procedure whenever PTCA fails to produce optimal results or causes acute vessel closure. Perhaps, another potential application of the LBA system is to aid localized delivery of pharmacologic agents and their thermal adhesion to superficial tissue at angioplastied sites.

Anopheles flavirostris incriminated as a vector of malaria and Bancroftian filariasis in Banggi Island, Sabah, Malaysia.

Seven villages in Banggi Island, Sabah, Malaysia, were surveyed four times to evaluate the roles of local mosquitoes as vectors of malaria and Bancroftian filariasis. 11 species of Anopheles were found biting man. 53.9% of the anophelines caught were An. flavirostris, 27.1% An. balabacensis, 6% An. donaldi and 4.2% An. subpictus. Infective malaria sporozoites, probably of human origin, were found in two of 336 An. flavirostris and 12 of 308 An. balabacensis. Sporozoites, probably of a non-human Plasmodium, were found in An. umbrosus. Nine of 1001 An. flavirostris and four of 365 An. balabacensis harboured L2 or L3 filarial larvae identified as those of Wuchereria bancrofti. This is the first record of An. flavirostris as a natural vector of malaria and W. bancrofti in Sabah.