Pulmonary haemorrhage in a patient with Kikuchi disease

Kikuchi disease is an immunologic disease and most commonly presents with cervical lymphadenopathy. It is usually self-limiting [1]. It is sometimes associated with systemic lupus erythematosus (SLE) [2], and can be associated with many complications including aseptic meningitis, neuropathy, brachial neuritis. It can also be associated with lymphoma, and may sometimes be misdiagnosed as such [3]. The following is the first reported case of Kikuchi disease associated with pulmonary haemorrhage. The patient died and no other cause of the pulmonary haemorrhage could be identified at post mortem.

Pulmonary artery diameters in premature infants: normal ranges

The aim of this study is to establish the norms for pulmonary arterial diameters in the premature infants. One hundred and thirty cross-sectional echocardiograms were performed on 62 premature neonates (23.4 weeks to 36 weeks gestation) in the Neonatal Intensive Care Unit. Except for small atrial septal defects/patent foremen ovale (< or =3 mm) or patent ductus arteriosus (PDA), babies with structural heart defects were excluded. The weight at echocardiography ranges from 470 grams to 2,445 grams, with a mean of 1,157 grams. The diameter of the pulmonary annulus (PA), left pulmonary artery (LPA) and right pulmonary artery (RPA) were measured at peak systole at predetermined sites. Sizes of the atrial septal defect and PDA were also measured, if present. There was no difference in the diameter between the left and right pulmonary arteries (p=0.254, paired t-test) in the same patient. After controlling for weight, the mean diameters of the LPA and RPA were larger in patients with PDA (p=0.002) compared to those without PDA (p=0.002), while their pulmonary annulus were comparable in size (p=0.691). Between the gestational ages of 23 and 36 weeks, the diameter of PA, LPA and RPA correlated linearly with weight (Pearson R = 0.84, 0.82, 0.65 and 0.71, respectively; p<0.0005). Prediction graphs and regression equations are given. These normal ranges can be used for assessment of pulmonary artery diameters in premature neonates.

Echocardiographic features and management of neonatal ductal aneurysm

OBJECTIVES

To determine the case incidence of ductus arterious aneurysm among our neonates, and to report on our experience in the presentation, echocardiographic features, management and outcome of this condition.

METHODS

Retrospective review of cases diagnosed within a 1-year period from 1 July 1998 to 30 June 1999.

RESULTS

Eight cases of neonatal ductus arteriosus aneurysm (DAA) were diagnosed from 1 July 1998 to 30 June 1999. There were 998 new neonatal echocardiograms done during this period, giving us a case incidence of 0.8 per 100 echocardiograms. Only 1 patient was diagnosed antenatally, all others were detected incidentally on echocardiography done for other indications. None had symptoms related directly to the DAA and there was no suggestive mediastinal mass on chest X-ray. Majority were term infants (88%) and there was a predominance of male infants (75%). Three were associated with patent ductus arteriosus (PDA), while in the others, the ductus arteriosus were non-patent at first echocardiography. In the 3 infants whose ductus arteriosus was patent, the PDA was inserted into the pulmonary artery from an unusually superior direction. Close serial echocardiography on some of our patients suggested that resolution of the aneurysm is by thrombosis, manifesting as an echogenic area, followed by regression. In our series, 7 had total resolution, while 1 patient had a persistent echogenic area which became progressively smaller.

CONCLUSIONS

We found ductus arteriosus aneurysms in 0.8% of our neonatal echocardiograms. An unusually superior insertion of PDA into the pulmonary artery is a marker for its presence. Asymptomatic aneurysms resolve spontaneously and should be managed expectantly. Thrombosis plays a part in the resolution of ductal aneurysm.

Surfactant tracheobronchial lavage for the management of a rabbit model of meconium aspiration syndrome

We evaluated the effect of tracheobronchial lavage with diluted surfactant solution (bovine lipid extract surfactant, bLES) in a rabbit model of meconium aspiration. All animals were anaesthetized, tracheotomized and given 3-4 ml/kg of 25% slurry of human meconium into the endotracheal tube and mechanically ventilated for 1 h. The animals were then randomly assigned to surfactant lavage (n = 12) with 15 ml/kg of diluted surfactant at a concentration of 5.4 mg phospholipid/ml administered in aliquots of 2 ml; or simple endotracheal suction (control n = 12) when the oxygenation index (OI) was >/=15. Changes in the arterial blood gases and the histomorphological and radiological appearances of the lungs were recorded. The OI and arterial/alveolar oxygen tension (a/A PO2) of the surfactant lavage group improved significantly at 5 min post-treatment, and these improvements were observed throughout the ensuing 4 h of ventilation. There was significantly more solid content recovered by surfactant lavage compared with the control group (p = 0.0001). Radiologically, the post-treatment air space opacification scores of the lavage group were significantly lower compared with the control (p = 0.002). The post-treatment radiographs of the lavage-treated rabbits were rated by the radiologist, who was blinded to the treatment groups, as much improved in 5 and improved in 4, whereas the control rabbits were rated as much worse in 3 and worse in 4. Histological examination showed the lungs of the lavaged rabbits had significantly more normal airway (p < 0.0001), more fields showing completely normal airspace (p = 0.0001) and less fields showing severe overdistension with meconium (p = 0.0005). We concluded that lavage with diluted surfactant solution effectively washed out the meconium, improved gases exchanges, and improved the histological and radiological appearances in the rabbit model of MAS.

Many-body approach to the dynamics of batch learning

Using the cavity method and diagrammatic methods, we model the dynamics of batch learning of restricted sets of examples, widely applicable to general learning cost functions, and fully taking into account the temporal correlations introduced by the recycling of the examples. The approach is illustrated using the Adaline rule learning teacher-generated or random examples.

Error-correcting codes and image restoration with multiple stages of dynamics

We consider the problems of error-correcting codes and image restoration with multiple stages of dynamics. Information extracted from the former stage can be used selectively to improve the performance of the latter one. Analytic results were derived for the mean-field systems using the cavity method. We find that it has the advantage of being tolerant to uncertainties in hyperparameter estimation, as confirmed by simulations.

Coinfection of multiple strains of Epstein-Barr virus in immunocompetent normal individuals: reassessment of the viral carrier state

This study reassesses the occurrence of Epstein-Barr virus (EBV) diversity and coinfection versus dominance of a single viral strain within immunocompetent normal carriers. Polymerase chain reaction analysis of several different polymorphic loci of the EBV genome was performed on collections of peripheral blood mononuclear cells and multiple lymphoid and epithelial tissues of the same individuals. Autopsy specimens from 15 individuals who died of causes unrelated to EBV infection served as normal viral carriers. Unexpectedly, coinfection of multiple distinct strains of EBV of the same type (usually type 1) and less frequently of both types 1 and 2 was found to be very high within individual viral carriers. These data indicate that coinfection with multiple EBV strains is much more prevalent in normal carriers than previously appreciated, which in turn has direct implications on EBV persistence, host-viral interaction and pathogenesis.

Application of a luminescence-based pH optrode to monitoring of fermentation by Klebsiella pneumoniae

The application of an optical sensor based on immobilization of the ruthenium complex [Ru(bpy)2(dhphen)]2+ (bpy = 2,2'-bipyridine, dhphen = 4,7-dihydroxy-1,10-phenanthroline) in Nafion to pH monitoring of fermentation by Klebsiella pneumoniae is described. Interference from the culture medium can be eliminated by addition of a black microporous filter membrane (pore size: 0.45 microm) on top of the sensing film. The response of this pH optrode was found to show good correlation with the conventional pH electrode.

Monitoring the toxicity of phenolic chemicals to activated sludge using a novel optical scanning respirometer

This paper reports the development of optical scanning respirometer for determining the toxicity of chemicals to activated sludge. The respirometer is used to measure the dissolved oxygen concentration by monitoring the luminescence intensity of ruthenium dye immobilized in a polymer film in contact with the wastewater sample. The intensity is related to the extent of oxygen quenching of luminescence. The toxicity of chemicals can be evaluated by measuring the inhibition on respiration rate of microorganism using the scanning respirometer. The IC50 values (concentration of a chemical that exhibits 50% respiration inhibition) of various phenolic chemicals in activated sludge were determined. The performance of this method is compared with other toxicity methods. The experimental results indicate that the reproducibility and sensitivity of this respirometer are reasonably good.

Variable levels of mosaicism for trisomy 21 in a non-immune hydropic infant with chylothorax

We report the first case of mosaic trisomy 21 with non-immune hydrops fetalis and bilateral chylothoraces. Prenatal fetal blood karyotype analysis of 15 fetal cells revealed a 46,XX karyotype. Aggressive prenatal management, including fetal thoracocentesis and pleuro-amniotic shunt, was performed. A clinical phenotype of Down syndrome was apparent after the gross oedema had subsided. Subsequent chromosome study of neonatal blood lymphocytes showed mosaic trisomy 21 with 23 per cent trisomic cells. Review of the initial fetal blood sample identified trisomy in 5 per cent of 134 cells. Follow-up study at five months showed no trisomy 21 in 100 cells. This case illustrates the variable levels of mosaicism manifest in the peripheral blood of an infant with obvious Down syndrome phenotype, and the limitation of cytogenetic analysis of peripheral lymphocytes alone in prenatal and postnatal detection of low levels of mosaicism.

Statistical mechanics of image restoration and error-correcting codes

We develop a statistical-mechanical formulation for image restoration and error-correcting codes. These problems are shown to be equivalent to the Ising spin glass with ferromagnetic bias under random external fields. We prove that the quality of restoration/decoding is maximized at a specific set of parameter values determined by the source and channel properties. For image restoration in a mean-field system a line of optimal performance is shown to exist in the parameter space. These results are illustrated by solving exactly the infinite-range model. The solutions enable us to determine how precisely one should estimate unknown parameters. Monte Carlo simulations are carried out to see how far the conclusions from the infinite-range model are applicable to the more realistic two-dimensional case in image restoration.

Therapeutic communication strategies used by Hong Kong mental health nurses with their Chinese clients

Therapeutic communication is central to mental health nursing and through this process nurse-client relationships can be enhanced. In Hong Kong, mental health nurses are educated in 'western' theories and strategies in using therapeutic communication and the field of communication is predominantly Eurocentric. However, the majority of people in Hong Kong are Chinese and little research has been conducted into how Hong Kong nurses communicate with their Chinese clients. This qualitative study focused on identifying the therapeutic communication strategies used by mental health nurses with Chinese clients in Hong Kong. Three case study vignettes with some of the characteristics of Chinese culture were developed to elicit information about the strategies that respondents used in therapeutic communication. The purposive sample of 20 comprised 10 admission ward nurses and 10 community nurses from two psychiatric hospitals. All participants had at least five years post-registration experience. Content analysis revealed categories of communication and theme clusters for the nurses' response to the vignettes. The result showed a unique cultural influence emerged in communication patterns. In view of the scant nature of existing literature and studies in this area, this research provided some valuable data for further studies. Implications for mental health nursing education and practice in Hong Kong are raised, as are implications for nurses working in multicultural countries such as Australia, the UK and the USA, where there are significant numbers of Chinese clients who would benefit from nurses practising with a deeper understanding of communication strategies which are culturally bound.

Comparative analysis of Epstein-Barr virus gene polymorphisms in nasal T/NK-cell lymphomas and normal nasal tissues: implications on virus strain selection in malignancy

Whether particular Epstein-Barr virus (EBV) strains are preferentially selected in malignant diseases remains controversial. Assessment of the importance of strain variation in the pathogenicity of EBV has been hampered principally by the lack of accurate data on the prevalence of virus variants in the normal population. To clarify this issue, a detailed comparative analysis of the EBV genomes contained in normal nasal and nasopharyngeal mucosal tissues and in nasal T/NK-cell lymphoma, which originates at these anatomic sites, was carried out by PCR amplification across the 30-bp deletion and the 33-bp repeat loci in the LMP1 gene and the type-specific polymorphic loci in the EBNA2 and EBNA3C genes and by sequence analysis of the 3' C-terminal region of the LMP1 gene. Whilst the majority of EBV strains in either normal or tumour tissues were type 1 viruses with similar numbers of LMP1 repeats, a marked predominance of LMP1 deletion (del-LMP1) over non-deleted/wild-type LMP1 (wt-LMP1) variants was observed in nasal T/NK-cell lymphoma. Although del-LMP1 variants were also prevalent in the normal carriers of our population, wt-LMP1 was detected at a significantly higher frequency in normal vs. tumour tissues (p = 0.036). More critically, wt-LMP1 variants were found frequently in mixed infection with del-LMP1 variants in the normal carriers. Sequence analysis identified 2 major del-LMP1 (and several wt-LMP1) variants containing signatory nucleotide changes in relation to the prototype B95-8 sequence in both normal and neoplastic nasal tissues. Together, our data provide strong evidence for a selection mechanism for del-LMP1 over the wt-LMP1 variants in tumours.

Ammonia clearance by peritoneal dialysis and continuous arteriovenous hemodiafiltration

We report the use of continuous arteriovenous hemodiafiltration (CAVHD) in a neonate with severe hyperammonemia due to a urea cycle disorder. We compared the ammonia clearance (C(NH3)) for peritoneal dialysis (PD) and CAVHD. C(NH3) for CAVHD was 7.45 ml/min per m2 at a dialysate flow of 300 ml/h and was 10.55 ml/min per m2 at a dialysate flow rate of 600 ml/h. The mean PD clearance was 2.15 ml/min per m2. Our data suggest that CAVHD is superior to PD for the removal of plasma ammonia. We conclude that CAVHD should be considered a reasonable alternative in the treatment of neonatal hyperammonemia in urea cycle disorders when medical treatment fails.

Electrostatic enhancement of diffusion-controlled protein-protein association: comparison of theory and experiment on barnase and barstar

The electrostatic enhancement of the association rate of barnase and barstar is calculated using a transition-state theory like expression and atomic-detail modeling of the protein molecules. This expression predicts that the rate enhancement is simply the average Boltzmann factor in the region of configurational space where association occurs instantaneously in the diffusion-controlled limit. Based on experimental evidence, this "transition state" is defined by configurations in which, relative to the stereospecifically bound complex, the two proteins are shifted apart by approximately 8 A (so a layer of water can be accommodated in the interface) and the two binding surfaces are rotated away by 0 degrees to 3 degrees. The values of the average Boltzmann factor, calculated by solving the Poisson-Boltzmann equation, for the wild-type complex and 16 complexes with single mutations are found to correlate well with experimental results for the electrostatic rate enhancement. The predicted rate enhancement is found to be somewhat insensitive to the precise definition of the transition state, due to the long-range nature of electrostatic interactions. The experimental ionic strength dependence of the rate enhancement is also reasonably reproduced.

Five paediatric case reports of the use of adenosine in supraventricular tachycardia

The efficacy, safety and diagnostic usefulness of adenosine in the treatment of supraventricular tachycardia in children were prospectively studied over a 2-year period. Only patients who were stable and without hypotension were included. Adenosine was given at a dose of 0.1 mg/kg and increased to 0.2 mg/kg for the second and third doses if there was no response. Adenosine was used on 5 occasions in 5 patients. Adenosine was found to be effective in terminating supraventricular tachycardia in all 5 patients; 4 responded to a dose of 0.2 mg/kg while 1 responded to 0.1 mg/kg. Wolff-Parkinson White Syndrome was detected in 2 patients after termination of supraventricular tachycardia. Transient hypotension was noted in 1 patient lasting 45 seconds with no haemodynamic consequences. Two patients had transient ventricular ectopics lasting 3 to 5 seconds. One out of 3 patients who were old enough to report side-effects, experienced chest discomfort and dizziness lasting 5 seconds. All side-effects were transient and mild. We concluded that adenosine is effective and safe in terminating supraventricular tachycardia in children after vagal manoeuvres have failed.

Sphenoidal sinus mucocoele and yawning after radiation treatment for nasopharyngeal carcinoma

The long term complications of radiotherapy in treating patients with nasopharyngeal carcinoma (NPC) are well recognized. Among these, neurological and endocrinological complications are usually considered to be more clinically important. On the other hand, postirradiation sinusitis is often neglected or overlooked because symptoms are usually non-specific or not clinically disturbing. This leads to the under-reporting of this complication. We report the case history of a patient with NPC who developed recurrent and debilitating bouts of yawning attacks 13 years after radiotherapy. The attacks were thought to be due to the compression of the hypothalamus by a large mucocoele in the sphenoidal sinus, which was successfully managed by surgical drainage.

Transcatheter closure of patent ductus arteriosus using detachable spring coils

OBJECTIVE

To report our experience with transcatheter PDA closure using detachable spring coils.

METHODS

Suitable patients who presented between March 1996 to July 1997 were selected for coil occlusion of PDA after the diagnosis is confirmed on colour doppler echocardiography. Twenty-seven patients underwent an attempt at transcatheter closure of PDA with coils. Twenty-one were native ducts while 6 were residual ductal leaks following surgical ligation (4) and Rashkind umbrella occlusion (2).

RESULTS

The patients' age ranged from 20 months to 39 years (median 5.5 years) and weighed from 10.5 kg to 49 kg (median 21 kg). The PDA diameter ranged from 1.3 mm to 5 mm (mean 2.4 mm). Twenty-four patients had coils successfully deployed (one coil in each patient) and all had PDA diameter of < or = 3.5 mm. Seventeen had complete occlusion on echocardiographic colour doppler assessment within 24 hrs. Follow-up colour doppler assessment showed complete occlusion in all 24 patients by 6 months. There were no cases of coil embolisation or any other complications. Unsuccessful coil deployment was encountered in 3 patients with PDA diameter of > or = 4 mm.

CONCLUSION

The detachable coil system allows for complete control over coil release and therefore deployment is precise and complications are minimised. Transcatheter closure of PDA with the detachable coil is a safe and effective method especially for small ducts (< or = 3.5 mm).

Prevalence of six types of human papillomavirus in inverted papilloma and papillary transitional cell carcinoma of the bladder: an evaluation by polymerase chain reaction

AIMS

To study the prevalence of high risk oncogenic human papillomaviruses (HPV) in inverted papilloma and papillary transitional cell carcinoma of the bladder.

METHODS

Ten cases of inverted papilloma and 20 cases of papillary transitional cell carcinoma of the bladder from Chinese patients in Hong Kong were examined for the presence of HPV type 6, 11, 16, 18, 31, and 33 genomes using the polymerase chain reaction and HPV type specific primer probe combinations on paraffin wax embedded biopsy specimens.

RESULTS

Of the 10 cases of inverted papilloma, cases 1 and 6 showed the presence of HPV types 16 and 18, respectively. Six of the 20 papillary transitional cell carcinomas were positive for HPV type 18. The other HPV types were not detected.

CONCLUSIONS

HPV type 18 was found in 60% and 30% of cases of inverted papilloma and papillary transitional cell carcinoma of the bladder, respectively. These tumours were rarely associated with HPV types 6, 11, 16, 31, and 33. The role of HPV type 18 in oncogenesis of inverted papilloma and transitional cell carcinoma of the bladder requires further studies.

Design of fast enzymes by optimizing interaction potential in active site

The diffusional encounter between substrate and enzyme, and hence catalytic efficiency, can be enhanced by mutating charged residues on the surface of the enzyme. In this paper we present a simple method for screening such mutations. This is based on our earlier result that electrostatic enhancement of the enzyme-substrate binding rate constant can be accounted for just by the interaction potential within the active site. Assuming that catalytic and structural integrity is maintained, the catalytic efficiency can be optimized by surface charge mutations which lead to stronger interaction potential within the active site. Application of the screening method on superoxide dismutase shows that only charge mutations close to the active site will have practical effect on the catalytic efficiency. This rationalizes a large number of findings obtained in previous simulation and experimental studies.

Williams syndrome--the Singapore General Hospital experience

Williams syndrome first described in 1961 is generally characterised by mental deficiency, gregarious personality, unusual "elfin" facies, supravalvular aortic stenosis and idiopathic infantile hypercalcaemia. Patients with Williams syndrome show a hemizygous submicroscopic deletion of 7q11.23 detectable by fluorescent in-situ hybridisation (FISH). The deleted portion of the chromosome corresponds to the Elastin gene. We report 3 girls with characteristics of Williams syndrome in whom the diagnosis was confirmed by demonstration of the hemizygous deletion of 7q11.23 in the karyotype by FISH. These patients, aged 6, 7 and 10 years, showed the characteristic facies and gregarious personalities. Some developmental delay with mild mental deficiency and dysmorphic facies were prominent features in the initial presentation. Cardiac lesions found in these patients were small patent ductus arteriosus which closed, pulmonary valvular stenosis and mitral valve prolapse associated with mitral regurgitation respectively. Hypercalcaemia was not documented in these patients. Learning difficulty was a major issue and all patients required special schooling. Chromosome analyses done on peripheral blood were found to be normal in all patients. FISH using the Elastin Williams Syndrome Chromosome Region (WSCR) probes (oncor) showed the hemizygous deletion of 7q11.23. Diagnosis of Williams syndrome can now be confidently confirmed with the help of FISH.