Distributed feedback sol-gel zirconia waveguide lasers based on surface relief gratings

Distributed feedback waveguide lasers based on dye-doped sol-gel zirconia films with permanent grating structures were demonstrated. The permanent grating was realized by employing a novel epoxy-based azo-polymer that generates a surface relief grating by a photo-isomerization process induced by two interfering writing beams. When employing the rhodamine 6G dye, tuning of the output wavelength of the distributed feedback waveguide laser from around 575 nm to 610 nm can be achieved by adjusting the tilting angle between the orientation of the grating and the pump beam.

Thermal Stability of Cubic Boron Nitride Films Deposited by Chemical Vapor Deposition

Thermal stability of well-crystallized cubic boron nitride (cBN) films grown by chemical vapor deposition has been investigated by cathodoluminescence (CL), Raman spectroscopy, and scanning electron microscopy (SEM) with the cBN films annealed at various temperatures up to 1,300 degrees C. The crystallinity of the cBN films further improves, as indicated by a reduction of the relevant Raman line width, when the annealing temperature exceeds 1,100 degrees C. Structural damage or amorphization was observed on the grain boundaries of the cBN crystals when annealing temperature reaches 1,300 degrees C. The CL spectra are found to be unchanged up to 1,100 degrees C after annealing at 500 degrees C, showing the stability of the cBN films in electronic properties up to this temperature. New features were observed in the CL spectra when annealing temperature reaches 1,200-1,300 degrees C.

Exhaled nitric oxide levels are not correlated with eczema severity in Chinese children with atopic dermatitis

Asthma is a common atopic disease associated with atopic dermatitis (AD) and allergic rhinitis (AR). Exhaled nitric oxide level (eNO) has been found to be an interesting noninvasive marker of disease severity in children with asthma. However, it is uncertain if eNO may be confounded by any coexisting AD or AR. In this study, eNO in Chinese children with moderate-to-severe AD and no asthma symptoms (n = 53) was measured online by a chemiluminescence analyzer. Severity of AD was assessed using the objective SCORing-Atopic-Dermatitis score and coexisting allergic rhinitis with the Allergic-Rhinitis-Score (ARS). Patients with active symptoms of asthma or inhaled/intranasal corticosteroids were excluded. There was no difference in eNO between genders and no correlation between eNO and AD severity regardless of ARS or bronchial reactivity status. ENO appears to be a noninvasive marker whose level is independent of the two atopic diseases of AD and AR in children old enough to perform exhalation maneuver.

An evidence base for International Health Regulations: quantitative measurement of the impacts of epidemic disease on international trade

When cholera broke out in Mozambique, Kenya, Tanzania and Uganda in 1997, an urgent measure was filed with the Sanitary and Phytosanitary Committee of the World Trade Organization, by the European Union, citing the protection of human health, to limit imports of fish products. The authors analysed import data on specified products over time to quantify the trade impact of this measure. Using previous specific trade trends, the authors modelled expected trade flows and compared observed imports with expected imports to calculate the potential cost of lost trade. The conclusion of this analysis was that the impact of European restrictions on fish exports from Mozambique, Kenya, Tanzania and Uganda on the economies of these African countries was at least US dollar 332,217,415 for the years 1998 to 2002. Insights from such quantitative studies will be important in making policy choices under the revised International Health Regulations of the World Health Organization and should inform the discussion about the adoption of these regulations.

Study of intermolecular interactions in liquid nitrobenzene by depolarized hyper-Rayleigh scattering

We employed depolarized hyper-Rayleigh scattering (HRS) to investigate the intermolecular interactions in liquid nitrobenzene. By comparing the depolarization ratios of the second-harmonic scattered light from neat nitrobenzene and mixtures of nitrobenzene and methanol of varying mixing ratios, we demonstrated the existence of a coherent component of HRS in liquid nitrobenzene. The coherent component was found to essentially disappear at a sufficiently high dilution of the nitrobenzene liquid. We also observed that both localized orientational correlation and delocalized libron excitation contribute to coherent HRS in liquid nitrobenzene. The delocalized contribution to coherent HRS was found to diminish much more readily with the introduction of interstitial foreign molecules than the localized contribution.

Infective endocarditis in childhood: a seven-year experience

INTRODUCTION

The epidemiology, clinical features, treatment and outcomes of infective endocarditis (IE) are reviewed.

METHODS

A retrospective descriptive study was performed involving patients treated for IE at a paediatric tertiary centre in Singapore, between May 1997 and April 2004. Duke criteria were used to retrospectively evaluate the diagnosis of IE in these cases. Data analysis was performed using SPSS for Windows.

RESULTS

There were a total of 27 children with IE in the seven-year study period. Of these, 24 (88.9 percent) had congenital heart disease, one had rheumatic valvular heart disease and two had normal anatomy. Fever (81.5 percent) was the primary presenting symptom, while splenomegaly (40.7 percent) and septic spots (22.2 percent) were the most common physical findings. C-reactive protein was raised in all cases with a mean of 100.1mg/L. Blood cultures were positive in 77.8 percent of cases and the most common organism identified was Viridans Streptococcus species (25.9 percent). Vegetations were detected on echocardiography in 55.5 percent of cases. According to the Duke criteria, 48.1 percent of our patients fulfilled the clinical diagnosis of definite IE and 51.9 percent had possible IE. The median duration of parenteral antibiotics was 31 days. Major complications were seen in seven (25.9 percent) patients, of whom five had either left heart vegetations or a right-to-left shunt physiology.

CONCLUSION

IE is an uncommon infection in childhood and occurs primarily in patients with congenital heart disease. Rheumatic heart disease is rarely a predisposing cause in our local children. Early diagnosis of IE is challenging and depends on a high index of suspicion. Useful clues include the presence of splenomegaly, septic emboli, microscopic haematuria and high C-reactive protein level greater than 100mg/L. The Duke criteria for the diagnosis of IE are relevant locally, but if modified with an expanded list of minor criteria including the above useful clues, may increase the sensitivity of diagnosing definite IE. The presence of left-sided heart vegetations is a strong predictor of complications and must be treated aggressively.

A case of severe haemolytic disease of the newborn due to anti-Di(a) antibody

Red cell allo-antibodies directed against the Diego (Di) blood group antigen have rarely been reported to cause a haemolytic reaction against transfusion or haemolytic disease of the newborn. The frequency of the Di(a+) phenotype among the Hong Kong Chinese population is estimated to be 4.4%. We report on a case of severe haemolytic disease of the newborn due to anti-Di(a) antibody--the first local case to the best of our knowledge. Rare but clinically significant antibodies targeting red blood cells have to be considered in the investigation of haemolytic disease of the newborn when common underlying factors have been eliminated.

Transformation of diffuse large B-cell lymphoma into pre-B acute lymphoblastic leukemia: clinicopathologic features and clonal relationship

A patient with fibrosing alveolitis developed a diffuse large B-cell (DLBC) lymphoma that expressed CD20 and CD30. After an initial response, the lymphoma relapsed and was salvaged with further chemotherapy. After another remission of 3 years, a pre-B-cell acute lymphoblastic leukemia (ALL), which expressed CD10, CD19, CD22, CD79a, CD34 and terminal deoxyribonucleotidyl transferase, developed and led to death. Molecular analysis of the immunoglobulin heavy-chain gene showed that the initial lymphoma and its relapse were clonally related. At leukemic relapse, 2 clones related to the initial and relapsed lymphoma clones were present. DLBC lymphomas arise from post-follicle center B cells, whereas ALL arises from pregerminal B cells. Therefore, a direct transformation of DLBC lymphoma to ALL appears unlikely. The overall features suggest instead separate lymphoma and leukemic evolution from a common mutated B-cell precursor rather than transformation of DLBC lymphoma to ALL.

A case of cerebellar hypoplasia in a Chinese infant with osteogenesis imperfecta

We report a unique case of unilateral cerebellar hypoplasia in a young Chinese girl with osteogenesis imperfecta type IV. Magnetic resonance imaging showed mild basilar invagination and impression. Although unilateral cerebellar hypoplasia and osteogenesis imperfecta may have been coincidental diagnoses, we propose possible mechanisms for unilateral cerebellar hypoplasia secondary to osteogenesis imperfecta. For example, cerebellar hypoplasia may have been because of vascular disruption or direct compression to the posterior circulation in utero. Foetuses with osteogenesis imperfecta are more susceptible to the above risks compared to the normal foetus because of associated craniocervical anomalies and a poorly ossified skull.

Management of extremity soft tissue sarcoma after unplanned incomplete resection: experience of a regional musculoskeletal tumour centre

This study reviews the presentation and management of extremity soft tissue sarcoma after unplanned incomplete resection in a musculoskeletal tumour centre in Hong Kong. Medical records of 18 patients who were referred to our centre for further management from January 1995 to May 2001 after inadequate tumour excision were reviewed. Fourteen patients had been referred from private clinics and four from public hospitals. At initial presentation, 10 patients had lesions exceeding 5 cm, nine had a tumour deep in the subfascial plane, and eight had tumours that had recently increased in size. Sixteen had no preoperative radiological assessment or biopsy performed before excision. All except two patients needed additional skin and muscle reconstruction in a subsequent re-resection, and 12 required postoperative radiotherapy. Two patients subsequently developed distant metastases, and one patient died of an unrelated cause. No amputations were required, and no major complications arose from second surgery. Physicians' alertness towards the possible malignancy of soft tissue masses in extremities is important to avoid a potentially mutilating second resection. Well-planned re-resection in a specialised tumour centre can achieve satisfactory local control of disease.

Relation of arterial stiffness with gestational age and birth weight

BACKGROUND

The cardiovascular risk of individuals who are born small as a result of prematurity remains controversial. Given the previous findings of stiffer peripheral conduit arteries in growth restricted donor twins in twin-twin transfusion syndrome regardless of gestational age, we hypothesised that among children born preterm, only those with intrauterine growth retardation are predisposed to an increase in cardiovascular risks.

AIM

To compare brachioradial arterial stiffness and systemic blood pressure (BP) among children born preterm and small for gestational age (group 1, n = 15), those born preterm but having birth weight appropriate for gestational age (group 2, n = 36), and those born at term with birth weight appropriate for gestational age (group 3, n = 35).

METHODS

Systemic BP was measured by an automated device (Dinamap), while stiffness of the brachioradial arterial segment was assessed by measuring pulse wave velocity (PWV). The birth weight was adjusted for gestational age and expressed as a z score for analysis.

RESULTS

The 86 children were studied at a mean (SD) age of 8.2 (1.7) years. Subjects from group 1, who were born at 32.3 (2.0) weeks' gestation had a significantly lower z score of birth weight (-2.29 (0.63), p<0.001), compared with those from groups 2 and 3. They had a significantly higher mean blood pressure (p<0.001) and their diastolic blood pressure also tended to be higher (p = 0.07). Likewise, their brachioradial PWV, and hence arterial stiffness, was the highest of the three groups (p<0.001). While subjects from group 2 were similarly born preterm, their PWV was not significantly different from that of group 3 subjects (p = 1.00) and likewise their z score of birth weight did not differ (-0.01 (0.71) v -0.04 (1.1), p = 1.00). Brachioradial PWV correlated significantly with systolic (r = 0.31, p = 0.004), diastolic (r = 0.38, p<0.001), and mean (0.47, p<0.001) BP, and with z score of birth weight (r = -0.43, p<0.001). Multiple linear regression identified mean BP and z score of birth weight as significant determinants of PWV.

CONCLUSION

The findings of the present study support the hypothesis that among children born preterm, only those with intrauterine growth retardation are disadvantaged as a result of increase in systemic arterial stiffness and mean blood pressure.

A case of Langerhans' cell histiocytosis of the lung presenting with haemoptysis

Langerhans' cell histiocytosis of the lung can be part of a multisystem disorder or an isolated disorder. Ninety percent of adult patients with Langerhans' cell histiocytosis of the lung are smokers. This article reports a case of Langerhans' cell histiocytosis presenting with haemoptysis. The diagnostic signs on chest X-ray, high-resolution computed tomography, and histology are highlighted, followed by a short review of the literature.

Coronary normograms and the coronary-aorta index: objective determinants of coronary artery dilatation

This is a prospective study to establish the normal ranges of the proximal left (LCA) and right (RCA) coronary artery diameters in normal children. Echocardiographic measurements of the internal diameters of the LCA, RCA, and the aortic annulus (AoA) were performed on 390 Asians with normal hearts, between the ages of 2 months to 8 years. The maximal diameters of the LCA and RCA in diastole were measured at predetermined sites. The LCA and RCA diameters correlated linearly with age, height, weight, body surface area, as well as the AoA (Pearson's R > 0.8, p <0.005). Regression equations and z-score graphs were constructed. The coronary-aorta index (coronary artery to aortic annulus ratio) falls within a narrow range- LCA/AoA = 0.15 +/- 0.02 (range 0.09-0.21), RCA/AoA = 0.13 +/- 0.02 (range 0.09-0.20). This is independent of age, sex, weight, height, and body surface area. We have established reference ranges for proximal coronary artery diameters in normal children. The regression equations and z-score graphs for the LCA and RCA provide objective determination of coronary size abnormalities. The coronary-aorta index can serve as a quick guide to detect coronary dilatation.

Successful outcome after serial amnioreductions in triplet fetofetal transfusion syndrome

BACKGROUND

Triplet fetofetal transfusion is an extremely rare complication with high perinatal mortality. Its rarity does not allow any prospective randomized study on various interventional methods to be conducted.

CASE

We report one case of triplet fetofetal transfusion syndrome with survival of all three fetuses. Two were donor fetuses, and one was the recipient fetus. Serial amnioreductions were performed at 22, 24, and 26 weeks' gestation to relieve symptomatic polyhydramnios. Premature rupture of membranes occurred at 27 weeks and cesarean delivery was performed. All three babies were discharged home by 4 months of age, and all had normal neurological development when assessed at 6 months of age.

CONCLUSION

The option of serial amnioreduction, with the anticipation and preparation for delivery at around 28 weeks, should be seriously considered when triplet fetofetal transfusion syndrome is encountered.

All that wheezes is not asthma

Asthma is a common disease. Wheezing is not pathognomonic of asthma, however. One must be alert when appropriate asthmatic treatment does not provide adequate control. Other causes of airway obstruction must be considered, especially when stridor is heard. This report describes an elderly patient who had been managed as having asthma but had an endotracheal tumour.

Smith-Magenis syndrome and cyanotic congenital heart disease: a case report

We report a male newborn infant of Chinese descent with the Smith-Magenis (SMS) syndrome who presented with a severe cyanotic congenital heart disease. This report adds pulmonary atresia and ventricular septal defect to the spectrum of cardiac defects seen in SMS.

Cost-effectiveness of CT thorax and bronchoscopy in haemoptysis with normal CXR for exclusion of lung cancer

As fibre-optic bronchoscopy and CT thorax become more widely used, patients with haemoptysis who had normal CXR and sputum results are more commonly offered both CT and bronchoscopy to exclude lung cancer. Doctors who are under possible litigation pressure arising from missed diagnoses of lung cancer are often exhaustive in their investigations, even when the haemoptysis has been transient. The present study aims to investigate the number of cancer patients who can be detected with the two investigations, and compare recent similar study results with archive results. We found that despite the use of more efficient investigation tools, the yield is paradoxically much lower and, hence, less cost-effective than that of previous studies. The likely reason is that doctors tend to over-investigate, even for short-term, minimal blood-streaked sputum, which is common among simple bronchitis. In order to be more cost-effective, these investigations should be used more selectively and for high risk patients such as those with prolonged haemoptysis and those who are heavy smokers.

Highly efficient asymmetric epoxidation of alkenes with a D(4)-symmetric chiral dichlororuthenium(IV) porphyrin catalyst

A dichlororuthenium(IV) complex of 5,10,15,20-tetrakis[(1S,4R,5R,8S)-1,2,3,4,5,6,7,8-octahydro-1,2:5,8-dimethanoanthrance-9-yl]porphyrin, [Ru(IV)(D(4)-Por)Cl(2)] (1), was prepared by heating [Ru(II)(D(4)-Por)(CO)(MeOH)] (2) in refluxing CCl(4). Complex 1 is characterized by (1)H NMR (paramagnetically shifted pyrrolic protons at delta(H) = -52.3 ppm), FAB-mass spectroscopies, and magnetic susceptibility measurement (mu(eff) = 3.1 mu(B)). The ruthenium complex exhibits remarkable catalytic activity toward enantioselective alkene epoxidation using 2,6-dichloropyridine N-oxide (Cl(2)pyNO) as terminal oxidant. The Ru(IV)-catalyzed styrene epoxidation is achieved within 2 h (versus 48 h for the 2-catalyzed reaction), and optically active styrene oxide was obtained in 69% ee and 84% yield (875 turnovers). Likewise, substituted styrenes and some conjugated cis-disubstituted alkenes (e.g., cis-beta-methylstyrene, cis-1-phenyl-3-penten-1-yne, 1,2-dihydronaphthalene, and 2,2-dimethylchromenes) are converted effectively to their organic epoxides in 50-80% ee under the Ru(IV)-catalyzed conditions, and more than 850 turnovers of epoxides have been attained. When subjecting 1 to four repetitive uses by recharging the reaction mixture with Cl(2)pyNO and styrene, styrene oxide was obtained in a total of 2190 turnovers and 69% ee. UV-vis and ESI-mass spectral analysis of the final reaction mixture revealed that a ruthenium-carbonyl species could have been formed during the catalytic reaction, leading to the apparent catalyst deactivation. We prepared a heterogeneous chiral ruthenium porphyrin catalyst by immobilizing 1 into sol-gel matrix. The heterogeneous catalyst is highly active toward asymmetric styrene epoxidation producing styrene oxide in 69% ee with up to 10,800 turnovers being achieved. The loss of activity of the Ru/sol-gel catalyst is ascribed to catalyst leaching and/or deactivation. On the basis of Hammett correlation (rho(+) = -1.62, R = 0.99) and product analysis, a dioxoruthenium(VI) porphyrin intermediate is not favored.

Prevention of recurrent central venous stenosis using endovascular irradiation following stent placement in hemodialysis patients

This study was done to evaluate the outcome after brachytherapy (BT) given to prevent restenosis after stent insertion for central venous stenosis in patients with ipsilateral hemodialysis arteriovenous fistulas (AVF). Angioplasty and stenting were performed on 9 primary central venous stenoses in 8 patients with AVF followed by BT, delivering Iridium-192 radiation using an afterloading technique. BT was also administered to three patients with five recurrent stenoses at the stent margins. There was no residual stenosis after angioplasty and stenting. Venographic follow-up (77-644 days, mean 272 days) showed no restenosis in seven primary stenoses. New strictures (45%-100%) developed at the stent margin in six veins (five patients). Angioplasty or stenting was performed for five margin stenoses in three patients, followed by a second BT. Residual stenosis before BT was 0-30%. In our venographic follow-up (140-329 days, mean 215 days), three restenoses occurred (35%-100%). All progressed to complete occlusion on later venographic follow-up irrespective of whether BT was given to the stent margin or not. The mean primary and assisted primary patency of the central veins were 359 days and 639 days, respectively. Endovascular irradiation with a noncentering source does not prolong the patency after angioplasty and stenting of central venous stenosis in hemodialysis patients.

Comparison of treatment response patterns following scaling and root planing in smokers and non-smokers with untreated adult periodontitis

The present study was conducted to compare short-term treatment response patterns following scaling and root planing in smoking and non-smoking Chinese patients with untreated adult periodontitis. Thirteen smokers and twelve periodontally matched non-smokers with untreated advanced adult periodontitis were evaluated prior to and at one, three, and six months after scaling and root planing. Probing depths (PD), probing attachment level (PAL) and gingival height (GH) were assessed at clinically healthy, gingivitis and periodontitis sites. PD and PAL were measured using electronic Florida pocket and disk probes, respectively. Non-smokers consistently showed significant gingival shrinkage in gingivitis sites, whereas smokers had no significant change in GH. In periodontitis sites, both groups exhibited significant decreases in PD (p < 0.001) at one month, and a greater reduction of PD was found in non-smokers than in smokers (p < 0.05), the difference being most notable at three months (2.4 +/- 0.2 mm vs. 1.1 +/- 0.3 mm, p < 0.001). Non-smokers showed a consistent gain of attachment in periodontitis sites from 0.5 +/- 0.2 mm at one month (p < 0.05) to 1.2 +/- 0.3 mm at six months (p < 0.001), whereas no significant gain of attachment was found in smokers until six months (0.5 +/- 0.2 mm; p < 0.05). Overall, the reduction of PD positively correlated with baseline PD in both smokers (p < 0.01) and non-smokers (p < 0.001), but when only the sites with an initial PD > or = 5 mm were considered, such a significant correlation was found only in non-smokers (p < 0.05). A positive correlation was also found between the change in PAL and baseline PD solely in non-smokers (p < 0.05). This study indicates that smokers have different treatment response patterns and healing dynamics compared to non-smokers following scaling and root planing, suggesting that for smoking patients a more intensive treatment regimen is needed for a better treatment outcome and reduced risk for further periodontal disease progression.

BCL10 somatic mutations rarely occur in gastric lymphoma: detection of high frequency of polymorphisms in BCL10 coding region

The BCL10 gene, recently isolated due to its involvement in the t(1;14)(p22;q32) of mucosa-associated lymphoid tissue B cell non-Hodgkin lymphoma (MALToma), was shown to have frequent somatic mutations and short deletions within the coding region in MALToma and a variety of other lymphomas and solid tumors. These observations have been recently questioned. In this study, we examined BCL10 gene mutations by direct sequencing of the entire coding region of the BCL10 gene, amplified from paired normal and tumor genomic DNAs, as well as tumor cDNAs, in 23 cases of primary gastric B cell non-Hodgkin lymphomas, comprising of 6 cases of MALToma and 17 cases of diffuse large cell (DLC) lymphoma. Heterozygosity due to three types of known polymorphisms in codon 5 (17.3%), codon 8 (21.7%), and codon 213 (8.6%) were observed in both normal germline DNA and tumor DNAs and tumor cDNAs in individual cases. In one case (4.3%) G/C heterozygosity in codon 8 in normal germline DNA was reduced to homozygosity (LOH) in tumor DNA and cDNA. Mutations inactivating BCL10 gene product function were not found in any of these cases. Moreover, post-transcriptional alterations were not indicated by abnormalities in BCL10 mRNA sequence in tumor cDNAs in these gastric lymphoma cases. Our results show that somatic mutations in the BCL10 gene rarely occur in gastric lymphoma and indicate that this gene is unlikely to be of pathogenetic significance in the majority of gastric lymphomas.