UiO66-Derived Catalyst for Low Temperature Catalytic Reduction of NO with NH3

Diesel exhaust emissions are major outdoor air pollutants. Reducing the emission of NOx by diesel commercial vehicles and related machineries is at present a great challenge. In this study, we synthesize a catalyst for low-temperature catalytic reduction of NO using calcinated UiO-66(Zr) as a host for the doping of cerium, manganese, and titanium by the incipient wetness impregnation, followed by the dispersion of 1.0 wt % platinum. A solid solution of Ce_0.15Zr_0.54Mn_0.11Ti_0.20O₂/1.0Pt (CZMTO/Pt) is synthesized as evident by the structural characterizations. The catalyst demonstrates significant NO reduction in the laboratory due to the synergistic effect of various elements, with NO conversion above 80% at 160 °C.

Obstructed jejunal duplication cyst in an infant

Intestinal obstruction in infancy due to duplication cyst is rare. This is a case of a three-month old boy presented to the hospital with symptoms and signs of intermittent intestinal obstruction for three-week duration. Investigation with ultrasound revealed a small bowel duplication cyst. Patient underwent successful segmental jejunal resection and made an uneventful recovery. He made significant weight gain at one-year follow-up. The diagnostic approach to infant with intestinal obstruction is described with special emphasis on ultrasonographic features of jejunal duplication cyst.

Expression of DNA damage response proteins in cervical cancer patients treated with radical chemoradiotherapy

OBJECTIVE

The management of locally advanced cervical cancer has improved significantly with the advent of cisplatin-based chemoradiotherapy (CRT) as the primary treatment regimen. Nevertheless, a significant proportion of patients fail to respond or relapse on this treatment and have a very poor prognosis. Our goal was to determine the prognostic value of a panel of proteins involved in detection and repair of DNA damage.

METHODS

We performed fluorescence immunohistochemistry, and used software analysis to assess expression of DNA damage response proteins ATM, DNA-PKcs, PARP-1, Ku70 and Ku86 in 117 pre-treatment specimens from patients with locally advanced cervical cancer. We compared expression to clinicopathologic correlates to determine prognostic significance.

RESULTS

Five-year progression-free survival was significantly lower in the low expressors than in high expressors of ATM (35% vs. 58%, p=0.044) and PARP-1 (24% vs. 61%, p=0.003), and showed a trend to significance for DNA-PKcs (30% vs. 60%, p=0.050). Low expression of the same proteins also correlated significantly with lower overall survival. In multivariable analysis, adjusted for FIGO stage and tumor size, low ATM and PARP-1 expression was significantly associated with both poorer progression-free and overall survival. Pairwise analyses indicated that expression levels of these proteins were correlated.

CONCLUSIONS

Expression of DNA damage response proteins in cervical cancer is associated with outcome in patients treated with CRT. Immunohistochemical analysis of these proteins may be useful in guiding treatment decisions in such patients.

Adjuvant hepatic intra-arterial iodine-131-lipiodol following curative resection of hepatocellular carcinoma: a prospective randomized trial

BACKGROUND

The purpose of the present study was to determine whether intrahepatic injection of (131)I-lipiodol (Lipiodol) is effective against recurrence of surgically resected hepatocellular carcinoma (HCC).

METHODS

From June 2001 through March 2007, this nationwide multi-center prospective randomized controlled trial enrolled 103 patients 4-6 weeks after curative resection of HCC with complete recovery (52: Lipiodol, 51: Control). Follow-up was every 3 months for 1 year, then every 6 months. Primary and secondary endpoints were recurrence-free survival (RFS) and overall survival (OS), respectively, both of which were evaluated by the Kaplan-Meier technique and summarized by the hazard ratio (HR). The design was based on information obtained from a similar trial that had been conducted in Hong Kong.

RESULTS

The Lipiodol group showed a small, and nonsignificant, improvement over control in RFS (HR = 0.75; 95 % confidence interval [95 % CI] 0.46-1.23; p = 0.25) and OS (HR = 0.88; 95 % CI 0.51-1.51; p = 0.64). Only two serious adverse events were reported, both with hypothyroidism caused by (131)I-lipiodol and hepatic artery dissection during angiography.

CONCLUSIONS

The randomized trial provides insufficient evidence to recommend the routine use of (131)I-lipiodol in these patients.

Latitudinal variation in top-down and bottom-up control of a salt marsh food web

The shrub Iva frutescens, which occupies the terrestrial border of U.S. Atlantic Coast salt marshes, supports a food web that varies strongly across latitude. We tested whether latitudinal variation in plant quality (higher at high latitudes), consumption by omnivores (a crab, present only at low latitudes), consumption by mesopredators (ladybugs, present at all latitudes), or the life history stage of an herbivorous beetle could explain continental-scale field patterns of herbivore density. In a mesocosm experiment, crabs exerted strong top-down control on herbivorous beetles, ladybugs exerted strong top-down control on aphids, and both predators benefited plants through trophic cascades. Latitude of plant origin had no effect on consumers. Herbivorous beetle density was greater if mesocosms were stocked with beetle adults rather than larvae, and aphid densities were reduced in the "adult beetle" treatment. Treatment combinations representing high and low latitudes produced patterns of herbivore density similar to those in the field. We conclude that latitudinal variation in plant quality is less important than latitudinal variation in top consumers and competition in mediating food web structure. Climate may also play a strong role in structuring high-latitude salt marshes by limiting the number of herbivore generations per growing season and causing high overwintering mortality.

Using percutaneous transhepatic cholangioscopic lithotripsy for intrahepatic calculus in hostile abdomen

BACKGROUND

Hepatolithiasis is a challenging condition to treat especially in patients with previous hepatobiliary surgery. Percutaneous Transhepatic Cholangioscopic Lithotripsy (PTCSL) is an attractive salvage option for the treatment of recurrent hepatolithiasis. We reviewed our experience using PTCSL in treating 4 patients with previous complex abdominal surgery.

METHODS

We studied the 4 patients who underwent PTCSL from October 2007 to July 2009. We reviewed the operative procedures, workflow of performing PTCSL in our institution and the outcome of the procedure. PTCSL was performed in our institution using 3 mm cholangioscope (Dornier MedTech(®)) and Holmium laser with setting at 0.8 J, 20 Hz and 16 W. This was performed through a Percutaneous Transhepatic Cholangio-catheter inserted by interventional radiologists.

RESULTS

There were 4 patients with a median age of 50 (43-69) years. The median duration of the condition prior to PTCSL was 102 (60-156) months. Three patients had recurrent pyogenic cholangitis (RPC) with recurrent intrahepatic stone. They all had prior complex hepatobiliary operations. The median duration of surgery was 130 (125-180) min. There was minimal intra-operative blood loss. The first procedure was performed under local anaesthesia and sedation, however, with experience the subsequent 3 patients had the procedure performed under general anaesthesia. The median size of bile duct was 18 (15-20) mm prior to the procedure. The number of stones ranged from one to three with the largest size of stone comparable to the size of bile duct. The median follow up was 18 (10-24) months. All patients were symptom free with neither stone recurrence or cholangitis at the last follow up.

CONCLUSION

PTCSL is a feasible and an effective treatment method for patients with recurrent biliary stone following complex abdominal surgery as the success rates from open surgery and endoscopic procedures are limited. Excellent results can be expected with this minimally invasive technique.

Is pancreaticoduodenectomy justified in elderly patients?

BACKGROUND

Although mortality & morbidity for pancreaticoduodenectomy (PD) have improved significantly over the last two decades, the concern for elderly undergoing PD remains. This study examines the outcome of the elderly patients who had pancreaticoduodenectomy in our institution.

METHODS

A prospective database comprising 69 patients who underwent pancreaticoduodenectomy between 2001 and May 2008 was analyzed. Using WHO definition, elderly patient is defined as age 65 and above in this study. Two groups of patients were compared [Group 1: Age ≤65 & Group 2: Age >65].

RESULTS

The mean age of our patients was 62 ± 11 years. There were 37 (54%) patients in Group 1 and 32 (46%) patients in Group 2. There was no statistical difference between the two groups in terms of gender and race. However, there were more patients in the Group 2 with >2 comorbidities (p = 0.03). The median duration of operation was significantly longer in Group 2 (550 min vs 471 min, p = 0.04). Morbidity rate in Group 2 was higher (56% vs. 44%, p = 0.04). There was higher proportion of post-operative pancreatic fistula (POPF) in the elderly group (37.5% vs. 16.7%, p = 0.05). Majority of them are Grade A POPF according to the ISG definition. The median post-operative length-of-stay (LOS) in hospital was 9 days longer in Group 2 (p = 0.01). Mortality rate between the 2 groups of patients was comparable (0% vs. 3%, p = 0.28).

CONCLUSION

Elderly patients are at increased risk of morbidity in pancreatocoduodenectomy, in particular POPF. However, morbidity and mortality rates are acceptable. It is therefore justified to offer PD to elderly patients who do not have significant cardiopulmonary comorbidities.

Feline non-repetitive mitochondrial DNA control region database for forensic evidence

The domestic cat is the one of the most popular pets throughout the world. A by-product of owning, interacting with, or being in a household with a cat is the transfer of shed fur to clothing or personal objects. As trace evidence, transferred cat fur is a relatively untapped resource for forensic scientists. Both phenotypic and genotypic characteristics can be obtained from cat fur, but databases for neither aspect exist. Because cats incessantly groom, cat fur may have nucleated cells, not only in the hair bulb, but also as epithelial cells on the hair shaft deposited during the grooming process, thereby generally providing material for DNA profiling. To effectively exploit cat hair as a resource, representative databases must be established. The current study evaluates 402 bp of the mtDNA control region (CR) from 1394 cats, including cats from 25 distinct worldwide populations and 26 breeds. Eighty-three percent of the cats are represented by 12 major mitotypes. An additional 8.0% are clearly derived from the major mitotypes. Unique sequences are found in 7.5% of the cats. The overall genetic diversity for this data set is 0.8813±0.0046 with a random match probability of 11.8%. This region of the cat mtDNA has discriminatory power suitable for forensic application worldwide.

Starting a laparoscopic hepatectomy programme

INTRODUCTION

Laparoscopic hepatectomy has been performed in many overseas centres. By avoiding long incisions associated with open hepatectomies, patients suffer less pain, recover faster and enjoy a shorter hospital stay. In Singapore, many centres have recently embarked on this approach. We believe that careful patient selection can facilitate scaling the learning curve. The aim of this study was to review our centre's initial outcome with laparoscopic anatomical liver resection when stringent selection criteria were applied.

METHODS

For our initial experience, we based our patient selection on criteria recommended by centres more experienced with laparoscopic hepatectomy. We selected only patients with small lesions confined to Couinaud's liver segments of II, III, IVB, V and VI. The surgical technique was similar in all cases, including intraoperative ultrasonography for localisation, ultrasonic shears and surgical staplers for parenchymal transection, and delivery of the specimen via a Pfannenstiel incision. No hand ports were used. Patients' records were retrospectively reviewed.

RESULTS

Between July 2006 and August 2007, we had five consecutive patients. Their median age was 50 (range 36-66) years. Four of these patients had hepatocellular carcinomas and one had a liver abscess. The median operation time was 275 (range 250-290) minutes, and median intraoperative blood loss was 400 (range 200-700) ml. The median hospital stay was four days.

CONCLUSION

At the initial stages of a laparoscopic hepatectomy programme, we propose that a stringent patient selection criteria coupled with the proper surgical expertise can ensure favourable outcomes, comparable to more established centres.

Triple therapy for neovascular age-related macular degeneration using single-session photodynamic therapy combined with intravitreal bevacizumab and triamcinolone

AIM

To evaluate the efficacy and safety of triple therapy consisting single-session photodynamic therapy (PDT), intravitreal bevacizumab (IVB) and intravitreal triamcinolone (IVTA) for treatment of neovascular age-related macular degeneration (AMD) METHODS: Consecutive patients with subfoveal choroidal neovascularisation (CNV) secondary to AMD were treated with PDT using a standard protocol immediately followed by 1.25 mg of IVB and 4 mg of IVTA. 1.25 mg of IVB was given at 3 months for residual leakage. Best-corrected Snellen visual acuity (BCVA) and fluorescein angiography (FA) were performed prior to treatment. BCVA, intraocular pressure (IOP) and presence of vitritis were documented at 1 and 6 weeks, 3 and 6 months. FA was repeated at 3 and 6 months. Outcome measures included visual improvement measured by logMAR equivalent, angiographic evident of leakage and safety profile.

RESULTS

36 eyes of 33 patients, aged 76.4 (SD 10.5) years with mean follow-up of 14.7 (6.9-19.2) months were analysed. Baseline logMAR acuity was 1.22 (0.71). The mean logMAR acuity was 1.14 (0.62) and 1.18 (0.63) at 3 and 6 months respectively. At 6 months, 61.1% (22/36) showed stable or gaining vision, and 27.8% (10/36) gained three or more lines. Twenty-eight eyes (77.8%) achieved CNV resolution by single session of triple therapy. One eye lost more than six lines due to retinal pigment epithelium rip, three eyes showed a significant cataract requiring surgery, and two showed persistent raised IOP at 6 months. None resulted in endophthalmitis or reported thromboembolic event.

CONCLUSIONS

Short-term results of single session triple therapy suggested that it might be a useful treatment option for neovascular AMD based on its low retreatment rates, sustainable CNV eradication result and visual gain achievement. However, the risk and benefits of using intravitreal triamcinolone in addition to combined PDT and IVB warrant further evaluation.

Evaluation of reflection and refraction in simulations of ultraviolet disinfection using the discrete ordinates radiation model

Simulations of UV disinfection systems require accurate models of UV radiation within the reactor. Processes such as reflection and refraction at surfaces within the reactor can impact the intensity of the simulated radiation field, which in turn impacts the simulated dose and performance of the UV reactor. This paper describes a detailed discrete ordinates radiation model and comparisons to a test that recorded the UV radiation distribution around a low pressure UV lamp in a water-filled chamber with a UV transmittance of 88%. The effects of reflection and refraction at the quartz sleeve were investigated, along with the impact of wall reflection from the interior surfaces of the chamber. Results showed that the inclusion of wall reflection improved matches between predicted and measured values of incident radiation throughout the chamber. The difference between simulations with and without reflection ranged from several percent near the lamp to nearly 40% further away from the lamp. Neglecting reflection and refraction at the quartz sleeve increased the simulated radiation near the lamp and reduced the simulated radiation further away from the lamp. However, the distribution and trends in the simulated radiation field both with and without the effects of reflection and refraction at the quartz sleeve were consistent with the measured data distributions.

Emergency Hartmann's procedure: morbidity, mortality and reversal rates among Asians

BACKGROUND

Hartmann's procedure and its reversal are associated with high cumulative morbidity rates. We assessed the outcomes of emergency Hartmann's procedures and permanent stoma rates among Asians.

METHODS

A retrospective review of all emergency Hartmann's procedure performed from 1996 to 2001 was performed.

RESULTS

Emergency Hartmann's procedure was performed in 98 patients with a median age of 68 years. These included 58 patients with cancer and 18 with diverticulitis; 77 patients had pre-existing comorbidities. The mortality and morbidity rates were 19% and 65%, respectively. Mortality was impacted by pre-existing respiratory or cardiac disease, age and ASA grade. Likewise, morbidity was significantly increased in the presence of comorbidities, including hypertension and cardiac disease, and age. On multivariate analysis, only age (p=0.003, OR=1.171) and respiratory disease (p=0.029, OR=11.05) affected mortality rates whilst hypertension (p=0.011, OR=5.85) and cardiac disease (p=0.044, OR=5.46) affected morbidity rates. Re-anastomosis was performed in 70 patients, and in 28 of these patients (40%) bowel continuity was re-established after a median of 9 months with a 7% morbidity rate. Reversibility was only related to patient age (p=0.011).

CONCLUSIONS

Hartmann's procedure is valid among Asians, and its mortality and morbidity rates are related to patients' pre-existing health conditions. The predominant cause is colorectal cancer and permanent stoma rates are related to patient age.

Incidence of neonatal chlamydial conjunctivitis and its association with nasopharyngeal colonisation in a Hong Kong hospital, assessed by polymerase chain reaction

OBJECTIVES

Using polymerase chain reactions, this study aimed to evaluate the incidence of neonatal chlamydial conjunctivitis in our region of Hong Kong and explore any association between such conjunctivitis and nasopharyngeal colonisation with Chlamydia trachomatis.

DESIGN

Prospective epidemiological study.

SETTING

Regional hospital, Hong Kong.

PATIENTS

Consecutive patients with neonatal conjunctivitis presenting to our hospital were recruited from May 2004 to April 2005 inclusive. Both eyes were investigated separately for Chlamydia trachomatis by polymerase chain reaction, direct immunofluorescent assay, and cell culture by two assigned ophthalmologists. Neonates diagnosed to have ocular Chlamydia trachomatis infection were subjected to additional nasopharyngeal investigations. Complete sets of ocular and nasopharyngeal investigations were also undertaken 1 week after oral erythromycin treatment to confirm complete eradication of Chlamydia trachomatis.

RESULTS

Of 192 patients with neonatal conjunctivitis, 24 were diagnosed to have chlamydial conjunctivitis. Fifteen of them had nasopharyngeal colonisation with Chlamydia trachomatis. Among the 20 neonatal chlamydial conjunctivitis patients that completed the follow-up study, one suffered treatment failure. None had clinically diagnosed systemic Chlamydia trachomatis infection 3 months after oral erythromycin.

CONCLUSIONS

The incidence of neonatal chlamydial conjunctivitis in our region of Hong Kong was 4 in 1000 live births, of whom 63% had nasopharyngeal presence of Chlamydia trachomatis. Owing to the high rate of nasopharyngeal isolation and possibility of treatment failure, post-treatment ocular and nasopharyngeal polymerase chain reaction testing for Chlamydia trachomatis may be considered to confirm complete eradication.

Cutaneous tuberculosis in Hong Kong: an update

OBJECTIVE

To provide an update on cutaneous tuberculosis in Hong Kong.

DESIGN

Retrospective study.

SETTING

Social Hygiene Service (Dermatology Division), the largest dermatological referral centre in Hong Kong.

PATIENTS

Patients presented with cutaneous tuberculosis between 1993 and 2002 inclusive. Case notes, histology reports, and microbiological reports were reviewed with particular reference to the epidemiology, duration of illness, history of contact with tuberculosis, culture results, and response to treatment.

RESULTS

There were 147 patients with cutaneous tuberculosis; among these a few had true cutaneous tuberculosis (n = 16) and the remainder were tuberculids (n = 131). In all they accounted for 0.04% of new dermatology cases diagnosed. Cases of cutaneous tuberculosis were distributed as follows: lupus vulgaris (n = 6, 4%), tuberculosis verrucosa cutis (n = 6, 4%), tuberculosis of the skin unclassified (n = 2, 1%), and orificial tuberculosis (n = 2, 1%). Culture and polymerase chain reaction was positive in less than half of the latter cases. All responded well to anti-tuberculosis therapy. Erythema induratum was the most common form (n = 127, 86%), but papulonecrotic tuberculids (n = 4, 3%) were uncommon. Erythema induratum affected the lower limb in all patients, with a female predominance, and responded to isoniazid monotherapy, multidrug anti-tuberculosis therapy, or doxycycline.

CONCLUSION

Lupus vulgaris and tuberculosis verrucosa cutis remain the commonest forms of true cutaneous tuberculosis, and erythema induratum is the most common tuberculid. Culture and polymerase chain reaction are positive in a small proportion of patients.

Moderate to severe obstructive sleep apnoea patients is associated with a higher incidence of visual field defect

PURPOSE

To compare the visual fields (VFs) and optic nerve head changes between obstructive sleep apnoea (OSA) in normotensive patients and an age-matched non-OSA population.

DESIGN

Case-control study.

PARTICIPANTS

A total of 41 ethnic Chinese patients diagnosed with moderate to severe OSA referred from the Sleep Laboratory, ENT Department, Tuen Mun Hospital. A total of 35 age-matched non-OSA subjects recruited from the Ophthalmology Department, North District Hospital.

METHODS

Comprehensive ophthalmological and systemic history, complete ophthalmological examination, including central-30 computerized perimetry for all studied patients.

MAIN OUTCOME MEASURES

Polysomnographic data, VF indices, optic disc changes.

RESULTS

In the OSA arm, VF indices were significantly subnormal and the incidence of suspicious glaucomatous disc changes was four times higher than that of the control arm. None of the studied patients suffered from any form of anterior segment complications.

CONCLUSIONS

Moderate to severe OSA is associated with a higher incidence of VF defect and glaucomatous optic nerve changes.

Epidemiology of leprosy and response to treatment in Hong Kong

OBJECTIVES

To review the reported trend of leprosy in Hong Kong.

DESIGN

Retrospective study.

SETTING

Three major leprosy clinics in Hong Kong.

PATIENTS

Leprosy patients registered between 1970 and 2004.

MAIN OUTCOME MEASURES

Incidence, rate of deformities, distribution of leprosy subtypes, age distribution, and relapses after therapy.

RESULTS

The incidence of leprosy has decreased from 3.2 per 100,000 population in 1970 to 0.088 per 100,000 population in 2004. The proportion of the three subtypes of leprosy has remained roughly equal. There have been 87 relapses within this period with 54 (62%) cases of lepromatous leprosy, 22 (25%) borderline leprosy, and 11 (13%) tuberculoid leprosy. The overall relapse rate was 6.7% (0.2 per 100 person-years); this can be subdivided as a relapse rate for multidrug therapy of 3.2% (0.33 per 100 person-years) and for dapsone monotherapy of 8.3% (0.2 per 100 person-years). The mean interval to relapse for multidrug therapy and dapsone monotherapy was 1.83 and 5.8 years, respectively. The mean duration till relapse for patients on dapsone monotherapy was 15.6 years.

CONCLUSION

Treatment with recommended WHO-multidrug therapy is effective and well tolerated. Dapsone monotherapy is no longer effective. Leprosy is well controlled in Hong Kong but continued surveillance is required to detect relapses and to ensure good patient compliance with treatment.

Atypical mycobacterial cutaneous infections in Hong Kong: 10-year retrospective study

OBJECTIVE

To review the epidemiology of atypical mycobacterial cutaneous infection in Hong Kong.

DESIGN

Retrospective study.

SETTING

Social Hygiene Service (Dermatology Division), the largest dermatological referral centre in Hong Kong.

PATIENTS

Patients with a diagnosis of atypical mycobacterial cutaneous infection based on clinical features, histopathology, with or without a positive culture during the period 1993 to 2002.

MAIN OUTCOME MEASURES

Epidemiological data, clinical features, histology, microbiological investigation, and treatment response.

RESULTS

Of 345,394 dermatological cases presented over the 10-year period, 33 (0.0096%) cases (19 male, 14 female) of atypical mycobacterial cutaneous infection were diagnosed. The most common type of infection was caused by Mycobacterium marinum (n=17, 51.5%), followed by Mycobacterium avium-intracellulare (n=3, 9.1%) and Mycobacterium chelonae (n=2, 6.1%). The upper limb, especially the hands and fingers, was the most common (69.7%) site of involvement. Tissue culture was positive in 18 (54.5%) cases. All biopsies showed granulomatous histology. Thirty-two patients received treatment and 31 responded. Twenty-six were treated with oral tetracycline group of antibiotics (minocycline, doxycycline, tetracycline). The duration of treatment ranged from 8 to 54 weeks (mean, 24 weeks). Mild transient adverse effects to treatment were reported in six cases.

CONCLUSION

Atypical mycobacterial infection is rare in Hong Kong. Because of the low sensitivity of traditional culture techniques, atypical mycobacterial infection may be underdiagnosed if only culture-confirmed cases are included. Polymerase chain reaction provides a rapid and sensitive method to improve diagnostic accuracy. Tissue culture is crucial to determine antimicrobial susceptibility. In our study, tetracycline group of antibiotics, especially minocycline, was an effective treatment, particularly in cases caused by Mycobacterium marinum.

Mutant p53 melanoma cell lines respond differently to CP-31398-induced apoptosis

BACKGROUND

p53, a commonly mutated gene in human cancers, participates in cell cycle arrest, DNA repair and apoptosis. A small pharmacological compound, CP-31398, was found to have the ability to promote proper p53 protein folding, activate p53 transcription of downstream targets, and slow tumour growth in mice. Additionally, CP-31398 was found to be able to convert mutant p53 to wild-type conformation in several cell lines.

OBJECTIVES

To examine if CP-31398 can revert all mutant p53 proteins to wild-type function.

METHODS

We studied a series of apoptotic responses to CP-31398 in three melanoma cell lines varying in p53 mutation status.

RESULTS

Upon a moderate dose of CP-31398 treatment (15 microg mL(-1)), only the wild-type p53 MMRU and the single p53 point mutation MeWo cells exhibited apoptosis. Another melanoma cell line, Sk-mel-110, containing multiple p53 mutations, did not exhibit apoptosis. Although CP-31398 enhanced overall p53 protein level, its ability to promote proper folding of p53 protein was limited to CP-31398-sensitive MMRU and MeWo cells. These sensitive cells showed an increased Bax and PUMA transcription, altered mitochondrial membrane potential, followed by the release of cytochrome c, and cleaved caspase-9 and caspase-3. We also demonstrated that Apaf-1 was not involved in CP-31398-mediated apoptosis.

CONCLUSIONS

Our results suggest that the ability of CP-31398 to revert mutant p53 proteins to wild-type conformation may be correlated to p53 mutational status. More studies are necessary, to further investigate the effect of CP-31398 on mutant p53 and its potential applications as an anticancer agent.

Shallow ablations in phototherapeutic keratectomy: Long-term follow-up

PURPOSE

To evaluate the long-term efficacy and safety of shallow ablations in phototherapeutic keratectomy (PTK) in patients with recurrent corneal erosions.

SETTING

Department of Ophthalmology, Tuen Mun Hospital, Hong Kong, China.

METHODS

A retrospective analysis of 13 consecutive eyes with recurrent corneal erosions treated by PTK from 1997 to 1999 was performed. All eyes failed to respond to conventional treatments, and all eyes had corneal erosions involving the visual axis. Outcome measures included number of recurrences, change in best corrected visual acuity (BCVA) and spherical equivalent (SE), and complications arising from the laser treatment.

RESULTS

Indications for PTK were recurrent corneal erosions secondary to minor abrasive trauma (9 eyes) and map-dot-fingerprint corneal dystrophy (4 eyes). The mean ablation depth was 4.6 microm (range 3.4 to 5.8 microm). Mean postoperative follow-up was 49.5 months (range 24 to 68 months). The overall success rate after only 1 treatment was 84.6%. Eleven of 13 eyes had a preserved or improved BCVA, while 2 eyes showed deterioration of 1 line on Snellen testing. Seven of 13 patients had no change in SE; the rest had a change of less than +/-0.50 diopters. There were no major complications.

CONCLUSIONS

The comparable success rate after a single treatment suggests that PTK may still be effective at a shallower depth than previously considered. Shallow ablations may have lower chances of complications associated with deeper ablations. Further studies involving a larger number of subjects are warranted.

Review of first year result of photodynamic therapy on age-related macular degeneration in chinese population

PURPOSE

To evaluate the effect of verteporfin therapy (Visudyne) on age-related macular degeneration (AMD) in Chinese patients. The baseline characteristic and the visual outcome will be compared with the treatment of AMD with photodynamic therapy study (TAP) and verteporfin in photodynamic therapy study (VIP).

DESIGN

Retrospective comparative case series.

METHOD

We recruited patients >50 years old, with best-corrected visual acuity >20/200 and fluorescein angiography documenting subfoveal either predominantly classic with greatest linear dimension <5400 mum or pure occult choroidal neovascularization (CNV) secondary to AMD. We applied non-thermal laser to the lesion 15 min after visudyne infusion as described in TAP study. Patients were followed up with fluorescein angiography every 3 months. Additional treatment would be offered if there was evidence of recurrence of CNV.

OUTCOME MEASURE

Baseline characteristic and visual outcome.

RESULT

In all, 46 eyes of 42 patients were enrolled at our centre from July 2002 to June 2003. They comprised 11 eyes with predominantly classic lesions and 35 eyes with pure occult lesion. The mean number of treatment sessions given was 2.9 in the first year. At the 12-month examination, there were 63 and 29% of patients showing visual improvement in predominantly classic and occult groups, respectively, while there were only 16% of patients in the TAP study and 12% of patients in the VIP study showing visual improvement in the same period.

CONCLUSION

Verteporfin therapy for subfoveal CNV is beneficial to Chinese patients with AMD at first year. The visual result seems to be better than that observed in Caucasian patients.

Crystallization of the RNA guanylyltransferase of Chlorella virus PBCV-1

RNA guanylyltransferase, or capping enzyme (E.C. 2.7.7.50) catalyzes the transfer of GMP from GTP to diphosphate-terminated RNA to form the cap structure GpppN. Chlorella virus capping enzyme expressed in E. coli has been purified, treated with GTP and crystallized. X-ray diffraction data have been collected from these crystals as well as for a mercury derivative obtained by soaking the crystals in thimerosal. Selenomethionine RNA guanylyltransferase was purified and crystallized in a similar fashion. The space group is C2221 and the cell parameters are a = 93.3, b = 214.9, c = 105.8 A. Two Hg atoms and two subsets of Se atoms have been localized using difference Patterson and Fourier methods, suggesting that there are two molecules per asymmetric unit.

Mirizzi syndrome: a diagnostic and operative challenge

INTRODUCTION

Mirizzi syndrome (MS) is an unusual complication of gallstone disease. The majority of cases are not identified pre-operatively, despite advances in imaging techniques.

MATERIALS AND METHODS

Eighteen cases of MS were treated between January 1997 and April 2002. The clinical presentation, modes of investigation, surgical management and outcome are retrospectively reviewed.

RESULTS

There were 13 female and 5 male patients, with a mean age of 60 years. Seven patients presented with the classical Charcot's triad. Ultrasonography (US) was the first imaging investigation in 13 patients and computerised tomography (CT) in the other five cases. Eleven patients had a successful endoscopic retrograde cholangio-pancreatography (ERCP) carried out. Diagnosis of MS was arrived at in seven patients following pre-operative imagings. Overall, 11 patients had Type 1 and seven patients had Type 2 MS. In the group with Type 1 MS, nine patients underwent open cholecystectomy, of whom six had concomitant common bile duct (CBD) exploration for stones and one patient with biliary stenosis had a hepaticojejunostomy bypass. Laparoscopic cholecystectomy was attempted in two patients, with successful completion in one case. In the group with Type 2 MS, four fistulas were closed surgically, the other three had biliary bypass procedures.

CONCLUSION

Mirizzi syndrome is an unusual condition that poses diagnostic and operative challenges to the surgeon. With a judicious approach during dissection and early recognition of its presence, bile duct injury can be avoided. Good outcome can be achieved with an appropriate surgical procedure.

A controlled study of sleep related disordered breathing in obese children

BACKGROUND

Unlike the adult sleep related disordered breathing (SDB) patients who are typically obese, the relation between obesity and childhood SDB is not clear.

AIMS

To investigate whether obese children are more at risk of obstructive SDB when compared to normal population, and whether this risk is potentiated by the presence of pharyngeal lymphoid tissue.

METHODS

Forty six obese children (age 10.8 (SD 2.3) years; BMI 27.4 (SD 5.1)), and 44 sex and age matched normal weight children (age 11.7 (SD 2.1) years; BMI 18 (SD 1.8)) were studied. All children underwent a set of physical examinations (including the upper airways) and sleep studies.

RESULTS

The obese children were different from the normal weight children in terms of type (predominantly obstructive), frequency, and severity of respiratory disturbances. Depending on the criteria used, 26% or 32.6% of obese children had SDB; 2.3% of normal controls had OAI > or =1 and 4.5% had RDI > or =5. Presence of SDB was related to presence of tonsils (size >2; range 0-4) (OR 12.67, 95% CI 2.14 to 75.17) and BMI (OR 1.20, 95% CI 1.08 to 1.33).

CONCLUSIONS

Results suggest that obese children are at increased risk of obstructive SDB; the presence of any pharyngeal lymphoid tissue enlargement in obese children should therefore be aggressively managed.

Superior masenteric vein thrombosis

A 43 year-old woman presented with severe non-specific abdominal pain of 1-week duration. She was on oral contraceptive pills for the past 6 years. Clinically patient appeared ill with no specific abnormal physical sign. Moderate amount of free fluid in the peritoneal cavity on ultrasound prompted an urgent abdominal computed tomography (CT) scan, which revealed thrombosis of the superior mesenteric vein. Further investigations revealed a hypercoagulable state with protein C deficiency. Patient responded well to anticoagulation and supportive therapy. One month later patient readmitted with vomiting and signs of intestinal obstruction. Barium study revealed a moderately long tight stricture at mid jejunum with proximal dilation. A by-pass surgery was carried out. She was well at 3 months follow-up.

Cervical necrotising fasciitis consequent to mastoid infection

We present a case of cervical necrotising fasciitis in a 56 year old man, secondary to a rare mastoid infection. The patient had coexisting diabetes mellitus and hypertension. He was treated with early surgical debridement followed by neck and chest reconstruction and radical mastoidectomy. Aggressive antibiotic therapy and supportive care was given. He recovered well with minimal residual functional deficit.

Hepatolithiasis--a case series

INTRODUCTION

Hepatolithiasis is an uncommon entity in Singapore. We reviewed the cases presented to our institution (a 1200-bedded restructured hospital) over a 5-year period.

MATERIAL AND METHODS

Twelve cases of hepatolithiasis were treated between December 1995 and July 2000 representing 0.77% of gallstone disease operated on in the same period. The clinical presentation, investigations, treatment and subsequent progress are presented.

RESULTS

The patients' ages ranged from 28 to 82 years. There was a male to female ratio of 5:7. All patients had upper abdominal pain at presentation; 10 patients had clinical evidence of cholangitis. Ultrasound was the commonest first line investigation but additional investigations, such as computed tomographic (CT) scan and various forms of cholangiography, were frequently necessary for complete delineation of the biliary disease. The intrahepatic stones were located predominantly in the left lobe of the liver. Parenchymal atrophy was seen in 83% of patients. Two patients underwent a biliary bypass operation only, 5 had a hepatic resection only, and 5 had combined procedures. Follow-up ranged from 4 to 50 months. Postoperative recovery was generally unremarkable. Complications included subphrenic abscess (1 patient), recurrent stricture (1 patient) and recurrent stones (1 patient). One patient had an elevated serum CA 19-9 preoperatively; a small villous adenoma was noted at the biliary stricture in the resected left lateral segment of the liver. There was no operative mortality.

CONCLUSION

Hepatolithiasis is uncommon in Singapore. Complete diagnosis requires a combination of imaging modalities. Surgery remains the mainstay of definitive treatment. With adequate treatment, good outcome is possible.

Trypanosoma brucei RNA triphosphatase. Antiprotozoal drug target and guide to eukaryotic phylogeny

The mRNA capping apparatus of the protozoan parasite Trypanosoma brucei consists of separately encoded RNA triphosphatase and RNA guanylyltransferase enzymes. The triphosphatase TbCet1 is a member of a new family of metal-dependent phosphohydrolases that includes the RNA triphosphatases of fungi and the malaria parasite Plasmodium falciparum. The protozoal/fungal enzymes are structurally and mechanistically unrelated to the RNA triphosphatases of metazoans and plants. These results highlight the potential for discovery of broad spectrum antiprotozoal and antifungal drugs that selectively block the capping of pathogen-encoded mRNAs. We propose a scheme of eukaryotic phylogeny based on the structure of RNA triphosphatase and its physical linkage to the guanylyltransferase component of the capping apparatus.

Environmental and occupational skin diseases in Taiwan

This presentation focuses on the four most important skin diseases in Taiwan thought to be of environmental and/or occupational origin. The majority of work-related dermatoses are contact dermatitis patients. Among occupational contact dermatitis patients, 58.5% involved irritant and 41.5%, allergic dermatitis. Electronics, hairdressing, medical practice, and construction were the most important occupations causing contact dermatitis. An endemic occurrence of chronic arsenism causing hyperpigmentation, keratosis, and cancer has been reported in Taiwan. Arsenical skin cancers present as multiple lesions at different disease stages. The skin cancers are usually found in non-sun-exposed areas. UVB exerts an inhibitory effect on the proliferation of arsenical cancers; this may explain its non-sun-exposed nature. An outbreak of premalignant and malignant skin lesions was reported among paraquat manufacturers in 1985. The skin lesions were mainly distributed over the sun-exposed areas. Photodamage and photocarcinogenesis revealed a strong association with exposure to bipyridines among paraquat manufacturers. In 1979, a mass poisoning occurred in Taiwan from cooking oil contaminated by polychlorinated biphenyls (PCBs). Over 60% of patients were in grades O-II by the Japanese classification. The blood PCB levels of the Taiwanese patients were found to be higher than those of the Yusho subjects.

An essential function of Saccharomyces cerevisiae RNA triphosphatase Cet1 is to stabilize RNA guanylyltransferase Ceg1 against thermal inactivation

Saccharomyces cerevisiae RNA triphosphatase (Cet1) and RNA guanylyltransferase (Ceg1) interact in vivo and in vitro to form a bifunctional mRNA capping enzyme complex. Here we show that the guanylyltransferase activity of Ceg1 is highly thermolabile in vitro (98% loss of activity after treatment for 10 min at 35 degrees C) and that binding to recombinant Cet1 protein, or a synthetic peptide Cet1(232-265), protects Ceg1 from heat inactivation at physiological temperatures. Candida albicans guanylyltransferase Cgt1 is also thermolabile and is stabilized by binding to Cet1(232-265). In contrast, Schizosaccharomyces pombe and mammalian guanylyltransferases are intrinsically thermostable in vitro and they are unaffected by Cet1(232-265). We show that the requirement for the Ceg1-binding domain of Cet1 for yeast cell growth can be circumvented by overexpression in high gene dosage of a catalytically active mutant lacking the Ceg1-binding site (Cet1(269-549)) provided that Ceg1 is also overexpressed. However, such cells are unable to grow at 37 degrees C. In contrast, cells overexpressing Cet1(269-549) in single copy grow at all temperatures if they express either the S. pombe or mammalian guanylyltransferase in lieu of Ceg1. Thus, the cell growth phenotype correlates with the inherent thermal stability of the guanylyltransferase. We propose that an essential function of the Cet1-Ceg1 interaction is to stabilize Ceg1 guanylyltransferase activity rather than to allosterically regulate its activity. We used protein-affinity chromatography to identify the COOH-terminal segment of Ceg1 (from amino acids 245-459) as an autonomous Cet1-binding domain. Genetic experiments implicate two peptide segments, (287)KPVSLYVW(295) and (337)WQNLKNLEQPLN(348), as likely constituents of the Cet1-binding site on Ceg1.

Three-Dimensional Dynamic Subtraction Contrast Enhanced Magnetic Resonance Angiography of the peripheral arteries--an initial experience

This is a prospective study with the objective of comparing Three Dimensional (3D) Dynamic Subtraction Contrast Enhanced Magnetic Resonance Angiography (3DDSCEMRA) with Conventional Catheter Arteriography (CCA) as the gold standard, in the diagnosis of peripheral occlusive disease. Three patients scheduled for CCA in this hospital in between September and October 2000 were included in this study. Patients underwent 3DDSCEMRA before proceeding to CCA on the same day. The 3DDSCEMRA reader was blinded to the CCA results. The results showed good correlation in iliofemoral segment and poor correlation in the infrapopliteal segment due to artifacts in 3DDSCEMRA images. 3DDSCEMRA is a new, non-invasive and promising technique in the diagnosis of peripheral occlusive disease.

Traumatic transection of aorta

A 16 year-old man presented with fracture of both his femurs after a road traffic accident. Chest radiograph revealed mediastinal widening. Subsequent CT scan and arch aortogram confirmed the findings of traumatic aortic arch transection at the isthmus. He underwent successful surgical repair. High index of suspicion and prompt actions are important in managing this potentially fatal but treatable condition.

Risk of betel chewing for oesophageal cancer in Taiwan

Among 104 cases of squamous-cell oesophageal carcinoma patients and 277 controls in Taiwan, after adjusting for cigarette smoking, alcohol consumption, and other confounders, we found that subjects who chewed from 1 to 495 betel-year and more than 495 betel-years (about 20 betel quid per day for 20 years) had 3.6-fold (95% Cl = 1.3-10.1) and 9.2-fold risk (95% Cl = 1.8-46.7), respectively, of developing oesophageal cancer, compared to those who did not chew betel.

A pilot evaluation of tibia lead concentrations in Taiwan

BACKGROUND

The aims of this study were to examine some of the factors that influence tibia lead concentrations, tibia lead x-ray fluorescence measurement uncertainty and blood lead concentrations, and to compare tibia lead concentrations in Taiwanese lead workers to those observed in lead workers from other countries.

METHODS

A pilot evaluation of 43 adult lead workers who underwent measurements of tibia lead and blood lead concentrations.

RESULTS

Mean and maximum tibia lead concentrations were 54 microg of Pb per g of bone mineral(microg/g) and 193 microg/g, respectively. Mean and maximum blood lead concentrations were 44 microg/dl and 92 microg/dl, respectively.

CONCLUSION

Past occupational control of lead exposure in Taiwan, ROC, did not prevent these workers from accumulating tibia lead concentrations greater than those in similar workers elsewhere in the world.

The length, phosphorylation state, and primary structure of the RNA polymerase II carboxyl-terminal domain dictate interactions with mRNA capping enzymes

The carboxyl-terminal domain (CTD) of elongating RNA polymerase II serves as a landing pad for macromolecular assemblies that regulate mRNA synthesis and processing. The capping apparatus is the first of the assemblies to act on the nascent pre-mRNA and the one for which binding of the catalytic components is most clearly dependent on CTD phosphorylation. The present study highlights a distinctive strategy of cap targeting in fission yeast whereby the triphosphatase (Pct1) and guanylyltransferase (Pce1) enzymes of the capping apparatus do not interact physically with each other (as they do in budding yeast and metazoans), but instead bind independently to the phosphorylated CTD. In vivo interactions of Pct1 and Pce1 with the CTD in a two-hybrid assay require 12 and 14 tandem repeats of the CTD heptapeptide, respectively. Pct1 and Pce1 bind in vitro to synthetic CTD peptides containing phosphoserine uniquely at position 5 or doubly at positions 2 and 5 of each of four tandem YSPTSPS repeats, but they bind weakly (Pce1) or not at all (Pct1) to a peptide containing phosphoserine at position 2. These results illustrate how remodeling of the CTD phosphorylation array might influence the recruitment and dissociation of the capping enzymes during elongation. But how does the CTD structure itself dictate interactions with the RNA processing enzymes independent of the phosphorylation state? Using CTD-Ser5 phosphopeptides containing alanine substitutions at other positions of the heptad, we define essential roles for Tyr-1 and Pro-3 (but not Thr-4 or Pro-6) in the binding of Schizosaccharomyces pombe guanylyltransferase. Tyr-1 is also essential for binding and allosteric activation of mammalian guanylyltransferase by CTD Ser5-PO4, whereas alanine mutations of Pro-3 and Pro-6 reduce the affinity for the allosteric CTD-binding site. These are the first structure-activity relationships deduced for an effector function of the phosphorylated CTD.

The activity in ex vivo expansion of cord blood myeloid progenitor cells before and after cryopreservation

A total of 50 human umbilical cord blood (UCB) samples were studied. The hematopoietic stem/progenitor (CD34+) populations were isolated from UCB mononuclear cells (MNC) by means of immunomagnetic separation. Double immunofluorescent staining of UCB CD34+ cells revealed that there was a high proportion (82.33 +/- 4.47%) of CD34+ cells co-expressing CD13, while the percentage of CD34+ CD33+ cells was much lower (22.17 +/- 3.35%). In contrast, for co-expressing lymphoid differentiation antigens, the proportion of CD34+CD38+ cells (38.34 +/- 6.09%) was relatively higher than that of CD34+CD10+ cells (11.52 +/- 1.24%) or CD34+CD2+ cells (9.84 +/- 2.30%). For stimulating the ex vivo expansion of UCB progenitor cells, no single hematopoietic growth factor (HGF) was efficacious when used alone, while combination of 4 HGFs, such as GM-CSF, G-CSF, IL-3, and SCF could induce a 55-fold increase in the myeloid progenitor cells, day-14 CFU-GM, in a short term of 7 days' liquid culture. Cryopreservation of UCB as MNC preparations at -196 degrees C could satisfactorily retain the number and activity of CD34+ cells. After thawing, a high recovery rate of about 80% CD34+ cells was obtained. When suspended in liquid cultures containing a combination of 4 HGFs, as shown above, the frozen cord blood progenitor cells could be well expanded, reaching a >50-fold increase in day-14 CFU-GM, which was very similar to that of the fresh UCB samples. In addition, a similar result was also seen in CFU-GEMM, indicating that after cryopreservation the recovered UCB progenitor cells retain an intact clonogeneic ability capable of efficiently responding to hematopoietic growth factors for ex vivo expansion.

Two episodes of ethylene oxide poisoning--a case report

Ethylene oxide is used as a sterilizer, a solvent, a plasticizer and in the manufacture of special solvents, antifreeze, polyester resins and non-ionic surfactants. Its toxicity is caused by an alkylating reaction with most organic substances in the body. Four workers, without any protection, managed the leakage of ethylene oxide from the collecting tank improperly on July 29, 2000. In the same factory, the overflow of ethylene oxide in process resulted in leakage of ethylene oxide again on Aug. 7, 2000. Two workers were poisoned despite wearing full-face respirators with ethylene oxide approved canisters. In these two events, the workers all smelled an ether-like odor. Six workers experienced nausea, vomiting, chest tightness, shortness of breath, dizziness, cough and ocular irritation. One worker had transient loss of consciousness. Oxygen therapy and supportive care were used. Patients were discharged in stable condition. The permissible exposure limit of ethylene oxide in air is 1 ppm as an eight hour TWA. Above 50 ppm, the odor threshold, a positive-pressure supplied air respirator is needed to protect the worker. Full-face respirators with ethylene oxide approved canisters could not protect our cases who smelled the odor and were exposed to an unknown concentration. It is important to wear positive-pressure self-contained breathing apparatuses equipped with full facepieces to clean up the contamination area and rescue the patients.

Importance of homodimerization for the in vivo function of yeast RNA triphosphatase

Saccharomyces cerevisiae RNA triphosphatase Cet1 is an essential component of the yeast mRNA capping apparatus. The active site of Cet1 resides within a topologically closed hydrophilic beta-barrel (the triphosphate tunnel) that is supported by a globular hydrophobic core. The homodimeric quaternary structure of Cet1 is formed by a network of contacts between the partner protomers. By studying the effects of alanine-cluster mutations, we highlight the contributions of two separate facets of the crystallographic dimer interface to Cet1 function in vivo. One essential facet of the interface entails hydrophobic cross-dimer interactions of Cys(330) and Val(331) and a cross-dimer hydrogen bond of Asp(280) with the backbone amide of Gln(329). The second functionally relevant dimer interface involves hydrophobic side-chain interactions of Phe(272) and Leu(273). Ala-cluster mutations involving these residues elicited lethal or severe temperature-sensitive phenotypes that were suppressed completely by fusion of the mutated triphosphatases to the guanylyltransferase domain of mammalian capping enzyme. The recombinant D279A-D280A and F272A-L273A proteins retained phosphohydrolase activity but sedimented as monomers. These results indicate that a disruption of the dimer interface is uniquely deleterious when the yeast RNA triphosphatase must function in concert with the endogenous yeast guanylyltransferase. We also identify key residue pairs in the hydrophobic core of the Cet1 protomer that support the active site tunnel and stabilize the triphosphatase in vivo.

HIV-1 Tat protein interacts with mammalian capping enzyme and stimulates capping of TAR RNA

HIV gene expression is subject to a transcriptional checkpoint, whereby negative transcription elongation factors induce an elongation block that is overcome by HIV Tat protein in conjunction with P-TEFb. P-TEFb is a cyclin-dependent kinase that catalyzes Tat-dependent phosphorylation of Ser-5 of the Pol II C-terminal domain (CTD). Ser-5 phosphorylation confers on the CTD the ability to recruit the mammalian mRNA capping enzyme (Mce1) and stimulate its guanylyltransferase activity. Here we show that Tat spearheads a second and novel pathway of capping enzyme recruitment and activation via a direct physical interaction between the C-terminal domain of Tat and Mce1. Tat stimulates the guanylyltransferase and triphosphatase activities of Mce1 and thereby enhances the otherwise low efficiency of cap formation on a TAR stem-loop RNA. Our findings suggest that multiple mechanisms exist for coupling transcription elongation and mRNA processing.

Detection of Kaposi sarcoma-associated herpesvirus in bone marrow biopsy samples from patients with multiple myeloma

BACKGROUND

Kaposi sarcoma-associated herpesvirus (KSHV) recently has been identified in the bone marrow (BM) dendritic cell of multiple myeloma (MM) patients. However, whether or not KSHV is associated with MM remains controversial because many studies have failed to detect the presence of KSHV DNA sequences in the BM of their MM patients.

METHODS

We have assayed for KSHV DNA sequences in the BM biopsy samples from 49 patients with MM and from 8 patients with normal BM, using nested polymerase chain reaction and dot blot analysis. The polymerase chain reaction product of KSHV was further determined by single-strand conformation polymorphism and sequence analyses.

RESULTS

KSHV DNA was detectable in 22 of 49 patients (44.9%) with MM but was not detectable in normal BM cells. Single-strand conformation polymorphism and sequence analyses showed that there were interpatient specific mutations. Sixteen out of 22 KSHV DNA sequences belonged to a previously defined subgroup, and the other 6 remain unclassified and may represent distinct strains of KSHV in Taiwan.

CONCLUSIONS

Data strongly supported that KSHV infection did exist in the BM of the current study patients with MM. However, the role of KSHV in the pathogenesis of multiple myeloma remains to be determined.

Transforming growth factor beta may act as an autocrine-survival-promoting factor for transformed trophoblasts

Using five trophoblast cell lines of different differentiation status, we have shown that trophoblasts could constitutively release the transforming growth factor beta-1 (TGFbeta1), but not TGFbeta2. Treatment of the human tumorigenic, TL, and BeWo cells with a differentiating agent and a potent protein kinase C activator--the tumor-promoting agent--or the JEG-3 cells with cholera toxin--a potent cyclic adenosine 3':5'monophosphate (cAMP) inducer--or its analogue 8-bromo-cAMP, potentiates TGFbeta production, but the two signaling pathways appear to be mutually exclusive. Surprisingly, the JAR tell line failed to respond to either type of TGFbeta activator. Based on reverse transcriptase (RT)-polymerase chain reaction (PCR), it was found that only the JAR cell line expressed messenger ribonucleic acid for decorin, a natural inhibitor of TGFbeta, and none of the cell lines had detectable protein expression as determined by immunocytochemical studies. The tell number in cultures with decorin was invariably lesser than in those without decorin under serum-free conditions for all the cell lines tested. These results suggest that TGFbeta may act as an autocrine-survival factor for transformed trophoblasts by allowing the cells to survive longer under a microenvironment which is not favorable for growth. Lastly, our results indicate that decorin, acting in a paracrine manner, may also play an important negative regulatory role in the development of transformed trophoblasts by sequestering TGFbeta, thereby preventing its action.

Enhanced prostaglandin E2 secretion in sputum from asthmatic patients after zafirlukast therapy

BACKGROUND AND PURPOSE

Leukotrienes are important inflammatory mediators of bronchial asthma that cause bronchoconstriction, mucous secretion, and increased vascular permeability. Current guidelines recommend anti-leukotriene agents as alternative treatments for asthma; however, data on their anti-inflammatory effect is lacking.

METHODS

The purpose of this study was to determine the anti-inflammatory effect of zafirlukast, a leukotriene antagonist, in patients with bronchial asthma. A total of 30 adult patients with mild persistent asthma received 6 weeks of zafirlukast treatment. Peak expiratory flow rate (PEFR) was determined before and after therapy to assess clinical efficacy. Both serum and sputum samples were collected before and after therapy and concentrations of eosinophil cationic protein (ECP), prostaglandin E2 (PGE2), and leukotriene E4 (LTE4) were measured.

RESULTS

A significant improvement in PEFR was found after zafirlukast therapy (p = 0.017). There was also a significant reduction in serum ECP concentration (13.6 +/- 2.4 micrograms/L vs 10.3 +/- 2.1 micrograms/L, p < 0.025) and a significant increase in sputum PGE2 concentration (112.7 +/- 14.0 pg/mL vs 176.8 +/- 32.1 pg/mL, p < 0.01). The percentage eosinophil count and the concentrations of ECP and LTE4 in the sputum were not significantly different after therapy.

CONCLUSION

This study found a significant reduction in serum ECP and a significant increase in sputum PGE2 concentrations in asthmatic patients after zafirlukast treatment, both of which were significantly associated with improvement in PEFR. The modulation of PGE2 and ECP production might occur through the anti-inflammatory effect of zafirlukast.

A yeast-like mRNA capping apparatus in Plasmodium falciparum

Analysis of the mRNA capping apparatus of the malaria parasite Plasmodium falciparum illuminates an evolutionary connection to fungi rather than metazoans. We show that P. falciparum encodes separate RNA guanylyltransferase (Pgt1) and RNA triphosphatase (Prt1) enzymes and that the triphosphatase component is a member of the fungal/viral family of metal-dependent phosphohydrolases, which are structurally and mechanistically unrelated to the cysteine-phosphatase-type RNA triphosphatases found in metazoans and plants. These results highlight the potential for discovery of mechanism-based antimalarial drugs designed to specifically block the capping of Plasmodium mRNAs. A simple heuristic scheme of eukaryotic phylogeny is suggested based on the structure and physical linkage of the triphosphatase and guanylyltransferase enzymes that catalyze cap formation.

Efficacy of zafirlukast in the treatment of patients with bronchial asthma

Zafirlukast is a drug newly used for the treatment of asthma. In this study, we examined the efficacy of zafirlukast on asthmatic patients and compared this efficacy between patients in different age groups and with different severities of pulmonary function. Patients concurrently inhaled long-acting beta2-agonist, corticosteroid or taken an oral aminophylline regimen, were treated with 20 mg oral zafirlukast twice daily for 6 weeks. In total, 32 asthmatic patients were included in the study. The primary efficacy measures included morning and evening peak expiratory flows (PEFs); secondary efficacy measures were the scoring of asthma symptoms including sleeping, coughing, and wheezing scores. Pulmonary functions including forced expiratory flow in 1 sec (FEV1), forced vital capacity (FVC), and PEF rate (PEFR) were examined during each clinical visit. Results showed that oral zafirlukast administration resulted in improvements in morning and evening PEFs and asthma symptom scores with the following statistical p values: morning PEF (285.8 vs 308.4 L/min), p = 0.003; evening PEF (293.3 vs 312.1 L/min), p = 0.007; coughing score (1.03 vs 0.72), p = 0.011; and wheezing score (0.71 vs 0.51), p = 0.009. As to the pulmonary function during the clinical visit, only the improvement of PEFR reached a statistically significant level (74.3 vs 82, p = 0.017). We compared the efficacy between asthmatic patients of different ages and those with different severities of pulmonary function. In patients aged below 50 years, those with FEV1 above 80% of the predicted value and FVC above 85% of the predicted value were more responsive to zafirlukast. In conclusion, we demonstrate the efficacy of zafirlukast in asthma therapy particularly for those patients who are younger and have better pulmonary function. When asthmatic patients do not respond to inhaled corticosteroid, long-acting beta2-agonist, or oral aminophylline, zafirlukast may provide an adjunct effect for asthma therapy.

RNA triphosphatase component of the mRNA capping apparatus of Paramecium bursaria Chlorella virus 1

Paramecium bursaria chlorella virus 1 (PBCV-1) elicits a lytic infection of its unicellular green alga host. The 330-kbp viral genome has been sequenced, yet little is known about how viral mRNAs are synthesized and processed. PBCV-1 encodes its own mRNA guanylyltransferase, which catalyzes the addition of GMP to the 5' diphosphate end of RNA to form a GpppN cap structure. Here we report that PBCV-1 encodes a separate RNA triphosphatase (RTP) that catalyzes the initial step in cap synthesis: hydrolysis of the gamma-phosphate of triphosphate-terminated RNA to generate an RNA diphosphate end. We exploit a yeast-based genetic system to show that Chlorella virus RTP can function as a cap-forming enzyme in vivo. The 193-amino-acid Chlorella virus RTP is the smallest member of a family of metal-dependent phosphohydrolases that includes the RNA triphosphatases of fungi and other large eukaryotic DNA viruses (poxviruses, African swine fever virus, and baculoviruses). Chlorella virus RTP is more similar in structure to the yeast RNA triphosphatases than to the enzymes of metazoan DNA viruses. Indeed, PBCV-1 is unique among DNA viruses in that the triphosphatase and guanylyltransferase steps of cap formation are catalyzed by separate viral enzymes instead of a single viral polypeptide with multiple catalytic domains.

An unusual case of organophosphate intoxication of a worker in a plastic bottle recycling plant: an important reminder

A young man was sent to our emergency unit because he had suffered from vomiting and cold sweating for 2 days. At the time he was admitted, he had no acute abdominal pains or gastrointestinal symptoms, and a physical examination revealed nothing but a faster heart rate and moist, flushing skin. The patient had worked for 6 years at a plastic bottle-recycling factory, but none of his co-workers had the same symptoms. Nevertheless, because the plant also recycled pesticide bottles, we suspected organophosphate pesticide intoxication. The patient's plasma acetylcholinesterase level was checked, revealing 1498.6 microU/L (normal range: 2,000-5, 000) on the first day and 1,379 microU/L on the second day. Upon questioning, the patient recalled that one of his shoe soles had been damaged and that his foot had been wet from walking all day in rain collected on the factory floor on the day that his symptoms first occurred. We conducted a study in the change of preshift and postshift acetylcholinesterase levels among six of his co-workers on a rainy day. We used the Wilcoxon signed rank test to compare the preshift and postshift plasma acetylcholinesterase levels; no significant difference was revealed (p = 0.600), leaving contamination via the damaged shoe sole suspect. We reviewed the literature on organophosphate intoxication; pesticide bottle-recycling factories were reported to be at a low risk of organophosphate toxicity in the working environment. However, because the potential risk of intoxication is still present, protective equipment such as clothing, gloves, and water-proof shoes should be worn, and employees should be educated on the potential risks.

A validity study of Ullanlinna Narcolepsy Scale in Hong Kong Chinese

OBJECTIVE

To validate the Chinese version of Ullanlinna Narcolepsy Scale (CUNS).

METHODS

A total of 234 subjects [163 male (69.7%) and 71 female (30.3%)] including 17 patients with narcolepsy, 21 normal controls and 196 patients with various sleep and psychiatric disorders were studied. The diagnoses of these patients were independently ascertained with sleep laboratory confirmation whenever indicated. All the subjects were interviewed through the telephone by a trained lay interviewer who was blind to the diagnosis. The questionnaire included demographic information, sleep habits and CUNS.

RESULTS

Narcoleptic patients had a significantly higher CUNS score (18.6+/-4.7; 95% confidence interval (CI) 16.2-21.0) and differentiated well from all the other groups (F(6,227)=28.4, P<0.001). The CUNS has a satisfactory internal consistency with Cronbach's alpha of 0.75. The principal component analysis with varimax rotation revealed two factors, namely sleepiness and cataplexy factors, which accounted for 45.5% of the total variance. The best cut-off point for the CUNS scale was found to be at 13/14 with high specificity (93.5%), sensitivity (94.1%), negative predictive value (NPV, 99.5%) and modest positive predictive value (PPV, 53.3%). The AUC of receiver operating characteristic (ROC) analysis was 0.97 (95% CI 0.95-0.99).

CONCLUSIONS

The CUNS was validated with satisfactory psychometric properties. The cross-cultural validation of UNS scale suggested that it could be used across the ethnic groups.

Ouabain resistance of a human trophoblast cell line is not related to its reactivity to ouabain

Ouabain is a specific inhibitor of sodium, potassium-dependent adenosine triphosphatase (Na,K-ATPase), a P-type ion-transporting ATPase which is essential for the maintenance of adequate concentrations of intracellular Na+ and K+ ions. The present study describes the establishment of a ouabain-resistant mutant, TLouaR, from a human trophoblast cell line TL. Morphologically TL and TLouaR are indistinguishable, but, TLouaR is about 1000 times more resistant to the cytotoxic effect of ouabain and > 2000 times to that of bufalin and yet ouabain can retard the growth of the TLouaR cells and in parallel reduce its cloning efficiency in a time- and dose-dependent manner. Furthermore, Na,K-ATPase activity from TLouaR cells is inhibitable by ouabain albeit with lower efficiency. [3H]ouabain binding studies reveal that TLouaR cells have less (P < 0.05) ouabain binding sites (1.7 +/- 0.15 x 10(4)/cell vs. 2.3 +/- 0.115 x 10(4)/cell in the control). However, affinities (dissociation constants Kd) to ouabain for TL and TLouaR cells are not significantly different. Lastly, Na,K-ATPase activity (1.375 +/- 0.25 micromole ATP/min mg protein) of TLouaR cells is significantly higher (P < 0.05) than that of the TL cells (0.895 +/- 0.12 micromole ATP/min x mg protein). These studies show that the interactions between ouabain and Na,K-ATPase can be mediated through different pathways resulting in diverse phenotypic characteristics. In addition, ouabain resistance does not necessarily reflect the lack of response to the digitalis drug. The exact mechanisms of ouabain resistance observed in the present study remain to be determined but the TLouaR cells may be the best tool to uncover the many functional characteristics of Na,K-ATPase.