A mutation panel comprising BRAFV600E, NRASQ61R, and NRASQ61H replicated retrospective histopathological examination findings in differentiating benign goitre from malignant papillary thyroid cancer in a cohort of Malaysian patients

Thyroid malignancy status is usually confirmed through histopathological examination (HPE) following thyroidectomy. In Malaysia, the application of molecular markers in pre-operative diagnosis of thyroid cancer remains unexplored. In this study, BRAF and NRAS gene mutation panel was assessed, and the results were compared with retrospective HPE findings. Malaysian patients with benign goitre (BTG: n=33) and papillary thyroid cancer (PTC: n=25; PTCa: n=20, PTCb: n=5) were recruited at Universiti Malaya Medical Centre from September 2019 to December 2022. PCR-direct DNA sequencing of BRAFV600, NRASG12, NRASG13, and NRASQ61 was conducted on DNA extracted from the patients' thyroid tissue specimens following thyroidectomy and HPE. BRAFV600E and NRASQ61R mutations showed absolute PTC-specificity with PTC-sensitivity of 32% and 28%, respectively. NRASQ61H demonstrated lower PTC-specificity (94%) but higher PTC-sensitivity (72%) compared to the BRAFV600E and NRASQ61R mutations. Although the NRASG12 and NRASG13 variants were absent in this study, a novel NRASV14D mutation was detected in a PTCa patient. Unlike PTCb, coexistence of BRAFV600E and NRASQ61 variants was commonly observed among the PTCa patients. Notably, all PTCb patients had NRASQ61H mutation with one patient carried both the NRASQ61H and BRAFV600E mutations. Association analysis revealed potential link between gender, BRAFV600E mutation and lymph node metastasis. In conclusion, mutation panel comprising BRAFV600E, NRASQ61R, and NRASQ61H did not discriminate the two PTC subtypes but replicated the retrospective HPE findings in differentiating BTG from PTC. The application of this mutation panel in pre-operative diagnosis of thyroid nodules requires further validation in a larger sample size, preferably incorporating fineneedle aspirate biopsies.

A nationwide survey on awareness and knowledge about Bronchial Provocation Test amongst doctors in Malaysia

BACKGROUND

Bronchial provocation test (BPT) is widely used internationally not only to evaluate bronchial responsiveness in conditions especially asthma, but is also utilized as a marker of control, severity and prognosis for asthma. However, the uptake of BPT in certain countries including Malaysia remains low. We aimed to explore this lack of knowledge by assessing the current level of awareness and knowledge on BPT amongst doctors in Malaysia.

MATERIALS AND METHODS

A nationwide web-based questionnaire targeting doctors was sent through social media (Facebook, WhatsApp and Telegram) and Malaysian Medical Association (MMA) mailing lists between 1 October 2020 - 5 February 2021.

RESULTS

In all 415 survey responses were analysed from doctors of various grades namely medical officers to consultants. A total of 404 (97.35%) encountered patients with asthma in their daily practice. According to specialty: 169 (40.72%) were from primary care, 121 (29.16%) internal medicine, 50 (12.05%) pulmonary medicine and 75 (18.07%) others. Only 163 (39.28%) were aware of BPT as a tool to diagnose asthma. 232 (55.90%) and 124 (29.88%) regarded BPT as an important test and felt confident to refer patients for BPT respectively. Of those participants who were not confident to refer: 35.17% were unsure of BPT indications, 33.21% were unsure of centres providing BPT, 8.17% cited logistic reasons, 6.04% were concerned of possible BPT side effects. 387 (93.25%) wanted more training in BPT. The median BPT knowledge score was 20% (1 out of 5). Awareness and knowledge were affected by specialty but not by: region of practice, gender, age and grade from logistic regression analysis.

CONCLUSION

Various national level programs and targeted local interventions are much needed to increase the awareness, knowledge and uptake of BPT in Malaysia.

Leptin and its receptor: can they help to differentiate chromophobe renal cell carcinoma from renal oncocytoma?

One of the challenges in differentiating chromophobe renal cell carcinoma (chRCC) from benign renal oncocytoma (RO) is overlapping morphology between the two subtypes. The aim of this study was to investigate the usefulness of expression of leptin (Ob) and its receptor (ObR) in discriminating chRCC from RO. Sections from paraffin-embedded, formalin-fixed tumour nephrectomy specimens of 45 patients, made up of 30 chRCC (15 eosinophilic variant and 15 non-eosinophilic variant) and 15 RO, were used in this study. Samples (30) of clear cell RCC (ccRCC), the most common histological subtype, were used to verify staining patterns found by others in our cohort of Australasian patients. Matched morphologically normal non-cancer kidney tissues were included for each specimen. Sections were batch-immunostained using antibodies against Ob and ObR. Stained sections were digitally scanned using Aperio ImageScope, and the expression pattern of Ob and ObR was studied. In this cohort, male to female ratio was 2:1; median age was 64 (45-88 years); and median tumour size was 3.8 cm (range 1.2-18 cm). There were 47 (62.7%) T1, seven T2, 20 T3 and one T4 stage RCC. Two patients with ccRCC presented with metastases. Nuclear expression of Ob was significantly higher in RO compared with chRCC. The increased nuclear expression of Ob in RO compared with chRCC may be a useful aid in the difficult histological differentiation of RO from chRCC, especially eosinophilic variants of chRCC.

Novel strategy for expression of authentic and bioactive human basic fibroblast growth factor in Bacillus subtilis

Inteins, also known as "protein introns," have been found to be present in many microbial species and widely employed for the expression and purification of recombinant proteins in Escherichia coli. However, interestingly, until now there has not been much information on the identification and application of inteins to protein expression in Bacillus subtilis. In this article, for the first time, despite the likelihood of absence of inteins in B. subtilis, this bacterium was shown to be able to facilitate auto-catalytic cleavages of fusions formed between inteins and recombinant proteins. Employing a construct expressing the intein, Ssp DnaB, (DnaB), which was fused at its N-terminus with the cellulose-binding domain (CellBD) of an endoglucanase encoded by the cenA gene of Cellulomonas fimi, the construct was demonstrated to be capable of mediating intracellular expression of basic fibroblast growth factor (bFGF), followed by auto-processing of the CellBD-DnaB-bFGF fusion to result in bFGF possessing the 146-residue authentic structure. The mentioned fusion was shown to result in a high yield of 84 mg l^-1 of biologically active bFGF. Future work in improving the growth of B. subtilis may enable the use of this bacterium, working in cooperation with inteins, to result in a new platform for efficient expression of valuable proteins.

Association of Cobb angle progression and neuraxial abnormality on MRI in asymptomatic Adolescent Idiopathic Scoliosis

BACKGROUND

Detection of neuraxial abnormality in neurologically asymptomatic adolescent idiopathic scoliosis (AIS) is crucial prior to surgery. It can only be detected on magnetic resonance imaging (MRI), which was not routinely done in this group of patient. On the other hand, whole spine radiographs for measurement of Cobb angle have been routinely included during clinic follow-up. This study aimed to determine the correlation between Cobb angle progression and neuraxial abnormality finding on MRI in asymptomatic AIS.

METHODS

A retrospective study was conducted in the Orthopaedic department of a tertiary hospital. Patients with asymptomatic AIS aged 10-20 years who attended scoliosis clinic from year 2007 to 2010 was reviewed. Patients who had whole spine MRI and two vertebral radiographs at least one year apart were further selected. Statistical analysis was done to see the association between Cobb angle progression and neuraxial abnormality on MRI.

RESULTS

The mean age at first presentation was 14.4 years old. Female (n=249) to male (n=50) ratio was 5:1. Only 19 patients fulfilled the selection criteria. There were 5 patients (26.3%) who had neuraxial abnormalities. The mean curve progression was 7.05° (range from -5° to 28°). Patients with and without neuroaxial abnormality showed mean curve progression of 0.6° and 9.36° respectively. There was no significant association between Cobb angle progression and neuroaxial abnormality (p=1.000).

CONCLUSION

Cobb angle progression is not a reliable indicator for predicting neuroaxial abnormality in patients with asymptomatic AIS. However, this study stressed the need to perform MRI prior to operation to document any associated neuraxial abnormality in clinically asymptomatic AIS patients.

Aetiological bases of 46,XY disorders of sex development in the Hong Kong Chinese population

OBJECTIVE

Disorders of sex development are due to congenital defects in chromosomal, gonadal, or anatomical sex development. The objective of this study was to determine the aetiology of this group of disorders in the Hong Kong Chinese population.

SETTING

Five public hospitals in Hong Kong.

PATIENTS

Patients with 46,XY disorders of sex development under the care of paediatric endocrinologists between July 2009 and June 2011.

MAIN OUTCOME MEASURES

Measurement of serum gonadotropins, adrenal and testicular hormones, and urinary steroid profiling. Mutational analysis of genes involved in sexual differentiation by direct DNA sequencing and multiplex ligation-dependent probe amplification.

RESULTS

Overall, 64 patients were recruited for the study. Their age at presentation ranged from birth to 17 years. The majority presented with ambiguous external genitalia including micropenis and severe hypospadias. A few presented with delayed puberty and primary amenorrhea. Baseline and post-human chorionic gonadotropin-stimulated testosterone and dihydrotestosterone levels were not discriminatory in patients with or without AR gene mutations. Of the patients, 22 had a confirmed genetic disease, with 11 having 5α-reductase 2 deficiency, seven with androgen insensitivity syndrome, one each with cholesterol side-chain cleavage enzyme deficiency, Frasier syndrome, NR5A1-related sex reversal, and persistent Müllerian duct syndrome.

CONCLUSIONS

Our findings suggest that 5α-reductase 2 deficiency and androgen insensitivity syndrome are possibly the two most common causes of 46,XY disorders of sex development in the Hong Kong Chinese population. Since hormonal findings can be unreliable, mutational analysis of the SRD5A2 and AR genes should be considered the first-line tests for these patients.

A community-based study of the relationship between somatic and psychological distress in Hong Kong

Although the predominantly somatic presentation of distress has been used to explain low rates of emotional illnesses and health service use in Chinese communities, this concept of somatization has not been examined by concurrently studying the profile of somatically and psychologically distressed Chinese individuals. A random population-based sample of 3014 adults underwent a structured telephone interview that examined their sociodemographic characteristics, somatic distress (Patient Health Questionnaire-15, PHQ-15), non-specific psychological distress (Kessler Scale-6, K6), health service use, and functional impairment. Four groups of individuals identified by PHQ-15 and K6 cut-off scores were compared. Results showed that PHQ-15 and K6 scores were positively correlated. The large majority of respondents (85.9%) reported both somatic and psychological distress. The proportions of Low Distress Group, Somatically Distressed Group, Psychologically Distressed Group, and Mixed Distress Group were 69.2%, 5.0%, 15.8%, and 10.0%, respectively. Specific age range, male gender, greater family income, higher education level, and retirement were associated with decreased odds of somatic and/or psychological distress. Although psychological distress best predicted impairment, somatic distress best predicted health service use. Mixed distress predicted most impairment and health service use. Thus, psychological distress and somatic distress commonly coexist across Chinese sociodemographic groups. This speaks against the conventional notion of somatization and is consistent with recent findings of a higher prevalence of emotional illnesses in Chinese people. That psychologically distressed individuals are more impaired but less inclined to seek help than somatically distressed individuals may partly explain low levels of help-seeking for mental disorders found in epidemiological studies.

Do recognizable lifetime eating disorder phenotypes naturally occur in a culturally asian population? A combined latent profile and taxometric approach

BACKGROUND

We examined whether empirically derived eating disorder (ED) categories in Hong Kong Chinese patients (N = 454) would be consistent with recognizable lifetime ED phenotypes derived from latent structure models of European and American samples.

METHOD

We performed latent profile analysis (LPA) using indicator variables from data collected during routine assessment, and then applied taxometric analysis to determine whether latent classes were qualitatively versus quantitatively distinct.

RESULTS

Latent profile analysis identified four classes: (i) binge/purge (47%); (ii) non-fat-phobic low-weight (34%); (iii) fat-phobic low-weight (12%); and (iv) overweight disordered eating (6%). Taxometric analysis identified qualitative (categorical) distinctions between the binge/purge and non-fat-phobic low-weight classes, and also between the fat-phobic and non-fat-phobic low-weight classes. Distinctions between the fat-phobic low-weight and binge/purge classes were indeterminate.

CONCLUSION

Empirically derived categories in Hong Kong showed recognizable correspondence with recognizable lifetime ED phenotypes. Although taxometric findings support two distinct classes of low weight EDs, LPA findings also support heterogeneity among non-fat-phobic individuals.

Logistic regression analysis of psychosocial correlates associated with recovery from schizophrenia in a Chinese community

BACKGROUND AND AIMS

More mental health services are adopting the recovery paradigm. This study adds to prior research by (a) using measures of stages of recovery and elements of recovery that were designed and validated in a non-Western, Chinese culture and (b) testing which demographic factors predict advanced recovery and whether placing importance on certain elements predicts advanced recovery.

METHOD

We examined recovery and factors associated with recovery among 75 Hong Kong adults who were diagnosed with schizophrenia and assessed to be in clinical remission. Data were collected on socio-demographic factors, recovery stages and elements associated with recovery. Logistic regression analysis was used to identify variables that could best predict stages of recovery. Receiver operating characteristic curves were used to detect the classification accuracy of the model (i.e. rates of correct classification of stages of recovery).

RESULTS

Logistic regression results indicated that stages of recovery could be distinguished with reasonable accuracy for Stage 3 ('living with disability', classification accuracy = 75.45%) and Stage 4 ('living beyond disability', classification accuracy = 75.50%). However, there was no sufficient information to predict Combined Stages 1 and 2 ('overwhelmed by disability' and 'struggling with disability'). It was found that having a meaningful role and age were the most important differentiators of recovery stage.

CONCLUSION

Preliminary findings suggest that adopting salient life roles personally is important to recovery and that this component should be incorporated into mental health services.

Meta-analysis of predictors of favorable employment outcomes among individuals with bipolar disorder

OBJECTIVES

Although several studies have reported on predictors of employment in individuals with bipolar disorder (BD), the magnitude of the impact of these variables is unclear as no previous studies have estimated the collective effect sizes (ESs). The present meta-analysis estimated ESs and explored which of these variables are associated with positive employment outcomes.

METHODS

We searched for articles published between 2000 and 2011 that reported associations between sociodemographic, clinical, psychosocial, and/or cognitive variables with employment outcomes in BD. Of the 781 articles identified, 22 met the inclusion criteria and were included in the final analysis (n = 6,301). Weighted correlation coefficients (r-index) were computed as ESs for each of the predictor variables, which were grouped into six categories: cognitive performance, symptomatology, sociodemographic factors, course of illness, clinical variables, and other personal factors. The overall ES (Rw) was estimated by assuming random-effect models. Sensitivity analyses were also performed to determine the robustness of the findings.

RESULTS

Significant predictors of favorable employment outcomes included: cognitive performance (e.g., verbal memory, Rw = 0.33; executive function, Rw = 0.26), sociodemographic factors (e.g., years of education, Rw = 0.23), course of illness (e.g., number of lifetime psychiatric hospitalizations, Rw = -0.35), symptomatology (e.g., depression, Rw = -0.25), and other personal factors (e.g., personality disorder, Rw = -0.49).

CONCLUSIONS

Overall, the cognitive performance and course of illness had larger average ESs than symptomatology or sociodemographic factors on favorable employment outcomes. These findings may help to guide the design of more effective work interventions for people with BD.

Differences and similarities between functional and personal recovery in an Asian population: a cluster analytic approach

This study gathers empirical data to test whether two forms of recovery are related: (1) the traditional outcome-based notion of recovery from a mental illness, which is called "functional recovery," and (2) the more recent, consumer-based concept of recovery in mental illness, which is called "personal recovery." A total of 150 Chinese outpatients were recruited, 75 with bipolar disorder and 75 with schizophrenia, as determined by structured clinical interview. Participants were reported to be in clinical remission for at least the previous 6 months by treating psychiatrists. Personal recovery was measured with the Stages of Recovery Scale, and functional recovery was measured with residential and employment status. In addition to clinical and demographic data, self-report measures included functioning (confirmed through chart review) and a survey of the participant's assessment of the importance of various elements of recovery. Personal recovery was significantly correlated with functional recovery; small effect size suggested that the two domains are far from identical. The strength of this correlation was stronger for participants with schizophrenia than for those with bipolar disorder. A cluster analysis also suggested that residential and employment statuses, along with personal recovery scores, were useful in differentiating participants. Patients were more likely to reach better recovery outcomes if they were female, married, had higher family income, and perceived social roles as less important to their recovery. Consistent with the consumer literature, personal recovery is related but still distinct from functional recovery. Personal recovery has more to do with life circumstances than with functioning status alone.

Gastrointestinal dysfunction in Chinese patients with fat-phobic and nonfat-phobic anorexia nervosa

Although gastrointestinal and other somatic symptoms are common in patients with anorexia nervosa (AN), and a growing cross-national literature indicates that not all anorexic patients exhibit the core diagnostic symptom of fat phobia, the relationship between somatic symptoms and anorexic illness remains unclear. Our objective was to evaluate gastrointestinal dysfunction (GD) in Chinese patients with fat phobic (FP) and nonfat phobic (NFP) anorexia nervosa. A total of 113 FP- and 28 NFP-AN outpatients underwent standardized clinical assessment and completed a new 8-item GD scale and other psychopathological measures. A majority (79.4%) of AN patients reported at least some gastrointestinal complaints on the GD scale (Cronbach's alpha = 0.78). FP-AN patients scored significantly higher than NFP-AN patients. The FP-AN with high GD group reported a higher level of specific and general psychopathology than the FP- and NFP-AN with low GD groups. Contrary to expectations, gastrointestinal symptoms were more common in FP-AN than NFP-AN patients. FP-AN with high GD was more severe than FP- and NFP-AN with low GD. The current fat phobic conceptualization of the anorexic illness may overlook its phenomenologic heterogeneity and reify a dichotomy that is inconsistent with patients' varied experience of food restriction.

Performance of the 6-item Kessler scale for measuring serious mental illness in Hong Kong

BACKGROUND

The 6-item Kessler scale (K6) promises to be a valuable epidemiological tool for assessing serious mental illness (SMI) in communities with limited resources for psychiatric research and treatment. Its performance in Chinese community has not been studied with reference to clinically assessed SMI.

METHOD

From a representative telephone-based population survey (n = 3014) that administered the K6, 153 participants were readministered the K6 and, on the same day, interviewed face-to-face by clinicians using the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorder, Fourth Edition, Axis I Disorder. Predictive indicators such as McNemar χ(2), area under receiver operating characteristic curve and stratum-specific likelihood ratios were used to investigate the concordance between the K6 and clinical status of SMI, individual-level predicted probabilities of having SMI, and the weighted prevalence of SMI in the community.

RESULT

The K6 exhibited high internal consistency and test-retest reliability. Factor analysis revealed 2 correlating components composed of depression and anxiety. Matching of K6 caseness and SMI status showed that at the cutoff of 12/13, the area under receiver operating characteristic curve was moderate (0.69). The K6 had high specificity and was a stronger screen-out than screen-in tool for SMI. The weighted prevalence estimate of SMI in Hong Kong was 6.5%. A person scoring 13 or above on the K6 has a probability of at least 22.2% of having SMI.

CONCLUSION

The Chinese K6 is reliable and generates the likelihood of SMI with substantial concordance with face-to-face clinical interviews in Hong Kong. It is a valuable tool for screening SMI, behavioral risk factor surveillance, and community epidemiological surveys.

Low prevalence of Dirofilaria immitis in dogs in Johor Bahru, Malaysia as a reflection of vector availability?

This study was conducted to investigate the low prevalence of Dirofilaria immitis in dogs in Johor Bahru as reported by veterinary practitioners, using wet blood mount, Knott's Concentration Test and two heartworm antigen test kits (IDEXX Canine SNAP® 4Dx and RapiGEN®). This study also compared the two test kits used and determined the microfilaria species. Blood were collected from 100 owned dogs and 50 stray dogs in Johor Bahru via cephalic venipuncture. A thick blood smear was done and examined for samples that were positive for microfilaria species identification. The overall prevalence of D. immitis in dogs in Johor Bahru was 1.33% (2/150) and the microfilaria identified was D. immitis. The prevalence of heartworm in owned and stray dogs in this study was 1% and 2% respectively. With only one false negative result from RapiGEN® test kit, comparing the sensitivity between the two test kits could not be achieved. The low prevalence of D. immitis found in this study confirmed anecdotal evidence that prevalence of dirofilariasis is indeed low in Johor Bahru. Additionally, we speculate that dirofilariasis in dogs might be considered as an indicator of vector availability.

A general population study of the Chinese Whiteley-7 index in Hong Kong

OBJECTIVE

To examine the psychometric properties of the Chinese seven-item Whiteley Index (WI-7) in the general population of Hong Kong.

METHODS

A random community-based telephone survey of 3014 respondents aged 15-65 was conducted using a fully structured questionnaire that included the WI-7, 15-item Patient Health Questionnaire (PHQ-15), Sheehan Disability Scale (SDS), and items about the frequency of health service use, perceived helpfulness of doctors, level of satisfaction with doctors, and sociodemographic variables. A sub-sample of 199 respondents was re-interviewed to assess test-retest reliability.

RESULTS

The WI-7 exhibited satisfactory internal consistency (Cronbach's α=0.73) and stable one-month test-retest reliability. The most commonly endorsed item was "worrying a lot about one's health" (55.7%), followed by "worrying about getting the disease oneself if it is brought to his/her attention" (48.7%) and "bothered by many different pains and aches" (33.9%). Age, gender, and monthly family income significantly predicted WI-7 score. Confirmatory factor analysis revealed that a 2-factor structure was superior to a 1-factor structure in fitting the data. WI-7 total score was positively associated with PHQ-15 somatic distress, SDS impairment, number of healthcare visits, lower levels of perceived helpfulness of doctors and of satisfaction with doctors.

CONCLUSION

The Chinese WI-7 exhibits satisfactory reliability and internal validity in a general population. It is a promising tool for the empirical examination of health anxiety which is a common experience with a mostly typical epidemiological profile among Chinese people in Hong Kong.

Cloning and characterization of a novel cellobiase gene, cba3, encoding the first known β-glucosidase of glycoside hydrolase family 1 of Cellulomonas biazotea

A novel cellobiase gene, designated cba3, was cloned from Cellulomonas biazotea. Although cellobiase genes of C. biazotea were previously cloned, published and/or patented, they encoded β-glucosidases all belonging to glycoside hydrolase family 3 (GH3); the new Cba3 cellobiase was identified to be a glycoside hydrolase family 1 (GH1) member, which represents the first discovered GH1 β-glucosidase of C. biazotea. Escherichia coli transformants expressing recombinant Cba3 were shown to grow readily in minimal media using cellobiose as the sole carbon source, supporting the conclusion that Cba3 is a genuine cellobiase. The full-length cba3 gene was revealed by sequencing to be 1344 bp long. Cba3 deletants lacking either the N-terminal 10 amino acids or the C-terminal 10 residues were found to be biologically inactive, supporting the importance of both ends in catalysis. Like other GH1 β-glucosidases, Cba3 was shown to contain the highly conserved NEP and ENG motifs, which are crucial for enzymatic activity. Despite lacking a classical N-terminal signal peptide, Cba3 was demonstrated to be a secretory protein. The findings that Cba3 is a cellobiase, and that it was expressed well as an extracellular protein in E. coli, support the potential of Cba3 for use with other cellulases in the hydrolysis of cellulosic biomass.

Molecular analysis of congenital adrenal hyperplasia due to 21-hydroxylase deficiency in Hong Kong Chinese patients

BACKGROUND

Congenital adrenal hyperplasia (CAH) caused by 21-hydroxylase deficiency (21OHD) is an autosomal recessive disorder due to mutation in the CYP21A2 gene.

OBJECTIVE

To elucidate the genetic basis of 21-hydroxylase-deficient CAH in Hong Kong Chinese patients.

PATIENTS AND METHODS

Mutational analysis of the CYP21A2 gene was performed on 35 Hong Kong Chinese patients with 21OHD using direct DNA sequencing and multiplex ligation-dependent probe amplification (MLPA).

RESULTS

The genetic findings of 21 male and 14 female patients are the following: c.293-13A/C>G (intron 2 splice site; 20 alleles), p.I172N (13), p.R356W (7), p.Q318X (4). A total of 20 mutant alleles contained gross deletion/conversion of all or part of the CYP21A2 gene. A novel mutation, c.1367delA (p.D456fs), was detected in one patient. One patient had only a heterozygous mutation detected. Out of 35 patients, 16 would have been incorrectly genotyped if either DNA sequencing or MLPA alone was used for molecular analysis.

CONCLUSIONS

The frequency of various mutations in the studied patients differs from those reported in other Asian populations. Gross deletion/conversion accounts for nearly one-third of the genetic defects. Therefore, laboratories must include methods for detecting point mutations as well as gross deletions/conversions to avoid misinterpretation of genotype. Genotyping has increasingly been proven to be a useful tool for supplementing, if not replacing, hormonal profiling for the diagnosis of 21OHD.

Enhancement of excretory production of an exoglucanase from Escherichia coli with phage shock protein A (PspA) overexpression

Production of recombinant proteins by excretory expression has many advantages over intracellular expression in Escherichia coli. Hyperexpression of a secretory exoglucanase, Exg, of Cellulomonas fimi was previously shown to saturate the SecYEG pathway and result in dramatic cell death of E. coli. In this study, we demonstrated that overexpression of the PspA in the JM101(pM1VegGcexL-pspA) strain enhanced excretion of Exg to 1.65 U/ml using shake-flask cultivation, which was 80% higher than the highest yield previously obtained from the optimized JM101(pM1VegGcexL) strain. A much higher excreted Exg activity of 4.5 U/ml was further achieved with high cell density cultivation using rich media. Furthermore, we showed that the PspA overexpression strain enjoyed an elevated critical value (CV), which was defined as the largest quotient between the intracellular unprocessed precursor and its secreted mature counterpart that was still tolerable by the host cells prior to the onset of cell death, improving from the previously determined CV of 20/80 to the currently achieved CV of 45/55 for Exg. The results suggested that the PspA overexpression strain might tolerate a higher level of precursor Exg making use of the SecYEG pathway for secretion. The reduced lethal effect might be attributable to the overexpressed PspA, which was postulated to be able to reduce membrane depolarization and damage. Our findings introduce a novel strategy of the combined application of metabolic engineering and construct optimization to the attainment of the best possible E. coli producers for secretory/excretory production of recombinant proteins, using Exg as the model protein.

Evidence for the 2008 economic crisis exacerbating depression in Hong Kong

BACKGROUND

There is a lack of population-level research on the relationship between economic contraction and specific mental disorders and how individual-level variables may mediate such a relationship.

METHODS

Two cross-sectional surveys using identical random sampling and diagnostic methods were conducted among Hong Kong adults in 2007 (January-February) and 2009 (April-May). 3016 and 2011 Chinese speaking adults completed structured interviews based on the criteria of Diagnostic and Statistical Manual of Mental Disorders (4th edition) (DSM-IV).

RESULTS

The twelve-month prevalence of DSM-IV major depressive episode (MDE) was significantly higher in 2009 (12.5%) than 2007 (8.5%). A significant increase of prevalence was found in both male and female respondents, those in the highest (55-65 years) age group, having secondary education level, were married/cohabited, divorced/widowed, employed, home-making, and in the lowest and high-middle income groups. Those with large investment loss had a significantly higher prevalence of MDE (20.3%) than those with less or no-investment loss (9.2-13.7%). The symptom pattern and severity of depression in 2007 and 2009 were similar.

CONCLUSION

Economic contraction triggered by a global financial crisis was associated with a significant increase in the risk of depression in the Hong Kong population. This increase was not explained primarily by unemployment and had a significant contribution from employed, home-making, high-middle income, and having married people. A holistic perspective that encompasses both ecological and individual levels of analysis is essential for studying the net impact of economic contraction on depression across communities and sociodemographic groups and for health policy planning.

Concordance between telephone survey classification and face-to-face interview diagnosis of one-year major depressive episode in Hong Kong

BACKGROUND

Community-based telephone surveys of depression have generated reliable findings but their concordance with standardized clinical diagnostic interviews is uncommonly examined, especially in non-western populations.

METHOD

106 consenting participants from a previous telephone-based population survey of major depressive episode (MDE) using a structured questionnaire were re-assessed face-to-face by clinical interviewers using the Structured Clinical Interview for DSM-IV Axis I Disorder (SCID-I). Receiver operating characteristic and other predictive indicators were used to investigate the concordance between the telephone survey instrument and SCID interview.

RESULT

The telephone survey instrument adequately classified MDE when the DSM-IV symptom number standard was fulfilled at moderate to severe levels of distress and impairment. It performed best when the cut-off was set at a severe level of distress or impairment in any one of four domains of functioning (AUC=0.76). Feeling useless, fatigue, loss of motivation and difficulty in concentration were the most prominent items for increasing the certainty of SCID-MDE diagnosis.

CONCLUSION

Classification of MDE by telephone-based structured interview of MDE exhibited generally good agreement with face-to-face clinical interview diagnosis in the Chinese population of Hong Kong. Further research on the telephone-based methodology should address inter-rater reliability, specificity of diagnosis, and variability of concordance across different mental disorder diagnoses and criteria of clinically significant impairment.

The changing profile of eating disorders at a tertiary psychiatric clinic in Hong Kong (1987-2007)

OBJECTIVE

To examine the clinical profile of Chinese eating disorder patients at a tertiary psychiatric clinic in Hong Kong from 1987 to 2007.

METHOD

Data on 195 consecutive patients were retrieved from a standardized intake interview by an eating disorder specialist. Patients seen between 1987-1997 (n = 67) and 1998-2007 (n = 128) and fat-phobic (n = 76) and nonfat-phobic (n = 39) anorexic patients were compared.

RESULTS

Patients were predominantly single (91.8%), female (99.0%), in their early-20s and suffered from anorexia (n = 115; 59.0%) or bulimia (n = 78; 40.0%) nervosa. The number of patients increased twofold across the two periods. Bulimia nervosa became more common while anorexia nervosa exhibited an increasingly fat-phobic pattern. Nonfat-phobic anorexic patients exhibited significantly lower premorbid body weight, less body dissatisfaction, less weight control behavior, and lower EAT-26 scores than fat-phobic anorexic patients.

DISCUSSION

The clinical profile of eating disorders in Hong Kong has increasingly conformed to that of Western countries.

Medical Practitioners Act 2007: the increased medical record burden

New medical record keeping obligations are implemented by the Medical Practitioners Act (2007), effective July 2009. This audit, comprising review of 347 medical entries in 257 charts on one day, investigated compliance with the Act together with the general standard of medical record keeping. The Medical Council requirement was absent all but 3 (0.9%) of entries; there was no unique identifier or signature in 28 (8%) and 135 (39%) of entries respectively. The case for change is discussed.

Prevalence and correlates of depression with atypical symptoms in Hong Kong

OBJECTIVE

Previous studies of atypical depression have been conducted in Western communities. There has been no community-based epidemiological study of atypical depression that covers the entire spectrum of bipolar disorders. The aim of the present study was to examine the 12 month prevalence of atypical depression and the differences in demographic and clinical profiles between depressed patients with and without atypical symptoms in the Chinese adult population of Hong Kong.

METHOD

A random sample of 3016 Chinese adults completed a telephone-based structured interview that examined their 12 month prevalence of major depressive episode. Atypical depression was defined as major depressive episode with hypersomnia and increased weight or appetite. Major depressive episode with and without atypical symptoms were compared on sociodemographic variables, number of depressive and manic/hypomanic symptoms, proportion of having lifetime mania/hypomania, suicidality, family psychiatric history, help-seeking behaviour, level of distress and role impairment.

RESULTS

The 12 month prevalence of atypical depression was 1.3%. Compared to non-atypical depression, atypical depression was associated with female gender, soft (subthreshold) bipolar II disorder, family psychiatric history, higher suicidality, more help-seeking from psychiatrists, and more depressive and manic/hypomanic symptoms. There was no difference in levels of distress or impairment.

CONCLUSIONS

Although limited by the lack of detailed information on comorbidity, bipolar family history, and age of onset, the findings support the hypothesis that atypical depression among Chinese people in Hong Kong exhibited prevalence and correlates similar to those found in Western epidemiological and clinical studies. Further research is warranted to examine its association with hypomania and how atypical depression may occupy a nosological position between typical unipolar depression and bipolar spectrum disorders.

A community survey of the twelve-month prevalence and correlates of bipolar spectrum disorder in Hong Kong

BACKGROUND

Recent community and clinical epidemiological studies have indicated that bipolar spectrum disorder (BSD) is a common illness. No community-based epidemiological study of BSD has been conducted in Chinese and other Asian populations.

METHOD

A random sample of 3016 Chinese adults underwent a telephone-based community survey that examined their twelve-month prevalences of BSD, sociodemographic characteristics, level of distress, and role impairment using the Sheehan Disability Scale. Bipolar I disorder (BP-I) and bipolar II disorder (BP-II) were based on DSM-IV criteria. Soft bipolar II disorder (Soft BP-II) fulfilled the DSM-IV criteria of major depressive episode and hypomanic episode except that the hypomanic/manic symptoms lasted two to three days.

RESULTS

The lifetime prevalences of manic episode, hypomanic episode, and soft hypomanic episode were 2.2%, 2.2%, and 10.7% respectively. The twelve-month prevalences of BP-I, BP-II, and Soft BP-II were 1.4%, 0.5%, and 1.8%, respectively. Respondents with BSD were more likely to be female, younger, and single than those without. Impairment and distress associated with depressive symptoms were similar across the three groups of bipolar disorders, but those associated with manic/hypomanic symptoms were more severe among respondents with BP-I than BP-II and Soft BP-II. The number of manic/hypomanic symptoms and depressive symptoms did not differ across the three bipolar groups.

LIMITATION

Structured interview questions based on core DSM-IV mood symptoms might under-estimate hypomania. Detailed sociodemographic information was not available.

CONCLUSION

BSD was common among Chinese people in Hong Kong and exhibited an epidemiological profile comparable to that of western societies.

Diagnosis of 5alpha-reductase 2 deficiency: a local experience

5Alpha-reductase 2 deficiency is an autosomal recessive disorder characterised by lack of masculinisation in XY individuals due to failure to convert testosterone to dihydrotestosterone, the bioactive androgen. Traditionally, the testosterone-to-dihydrotestosterone ratio is used to diagnose this condition but interpreting these results is not always straightforward, thus they may be inconclusive. On the contrary, urinary steroid profiling unambiguously demonstrates a significantly reduced excretion of 5alpha-reduced steroid metabolites compared to their 5beta counterparts. This analytical technique can also simultaneously confirm or rule out other causes of ambiguous genitalia due to steroidogenic defects. Making a DNA-based diagnosis by studying the SRD5A2 gene has become increasingly popular. Here, we report six Chinese patients from different families who were all diagnosed with 5alpha-reductase 2 deficiency based on urinary steroid profile findings and mutational analysis of the SRD5A2 gene. R227Q was the most commonly identified mutation in these patients. Management of sexual development disorders is also discussed.

Concordance between telephone survey classification and face-to-face structured clinical interview in the diagnosis of generalized anxiety disorder in Hong Kong

Telephone surveys of estimating mental disorders have been found to generate comparable findings to large-scale community surveys but the concordance between telephone instruments and clinical interviews is rarely examined. In this study, 100 Chinese respondents who had taken part in a telephone-based population survey of generalized anxiety disorder (GAD) in Hong Kong were administered the Structured Clinical Interview for DSM-IV Axis I Disorders (SCID-I) by clinical interviewers. The discriminability and predictive indicators of the telephone survey instrument were assessed using receiver operating characteristic analysis. Results showed that the telephone survey instrument identified individuals with a positive SCID diagnosis of GAD better than those without. Although its individual questions performed well in identifying the endorsement of the corresponding core SCID criterion of GAD, further studies are needed to find out the optimal combination of questions in the telephone instrument for identifying GAD in community surveys.

Does the pre-operative value of serum CA15-3 correlate with survival in breast cancer?

INTRODUCTION

CA15-3 is a well-known tumour marker for breast cancer. Currently it is not recommended for screening or diagnosis of breast cancer and its main application is in monitoring response to treatment in women with metastatic breast cancer. The aim of this study was to correlate serum CA15-3 at presentation with the stage of disease and overall survival in women with breast cancer in the University Malaya Medical Centre.

METHODS

This is a retrospective study of 437 women who had CA15-3 levels determined at initial presentation of breast cancer to UMMC between Jan 1999 and Oct 2003.

RESULTS

Of those patients who were adequately staged, CA15-3 was found to be elevated (defined as >51 U/ml) in 0% of Stage 1, 7.9% of Stage 2, 36.7% of Stage 3 and 68.6% of Stage 4 cases. In a subset of 331 patients with survival data, patients with normal CA15-3 had a 85% five year overall survival rate compared to 38% in their counterparts with elevation of the tumor marker. The level of elevation was also significantly related to survival; patients with values more than 200 U/ml exhibited only a 28% five year survival. The association of elevated CA15-3 at initial presentation with poor outcome was maintained over univariate and multivariate analyses.

CONCLUSION

Estimation of CA15-3 at presentation of breast cancer is important as it is an independent prognostic indicator and may prompt the physician to investigate for metastases if elevated.

How disease models in static networks can fail to approximate disease in dynamic networks

In the modeling of infectious disease spread within explicit social contact networks, previous studies have predominantly assumed that the effects of shifting social associations within groups are small. These models have utilized static approximations of contact networks. We examine this assumption by modeling disease spread within dynamic networks where associations shift according to individual preference based on three different measures of network centrality. The results of our investigations clearly show that this assumption may not hold in many cases. We demonstrate that these differences in association dynamics do yield significantly different disease outcomes both from each other and also from models using graph-theoretically accurate static network approximations. Further work is therefore needed to explore under which circumstances static models accurately reflect constantly shifting natural populations.

Prevalence of microplastics in Singapore's coastal marine environment

Microplastics have been recently identified as marine pollutants of significant concern due to their persistence, ubiquity and potential to act as vectors for the transfer and exposure of persistent organic pollutants to marine organisms. This study documents, for the first time, the presence and abundance of microplastics (>1.6 microm) in Singapore's coastal environment. An optimized sampling protocol for the collection and analysis of microplastics was developed, and beach sediments and seawater (surface microlayer and subsurface layer) samples were collected from nine different locations around the coastline. Low density microplastics were separated from sediments by flotation and polymer types were identified using Fourier transform infrared (FTIR) spectrometry. Synthetic polymer microplastics identified in beach sediments included polyethylene, polypropylene, polystyrene, nylon, polyvinyl alcohol and acrylonitrile butadiene styrene. Microplastics were detected in samples from four out of seven beach environments, with the greatest quantity found in sediments from two popular beaches in the eastern part of Singapore. Polyethylene, polypropylene and polystyrene microplastics were also found in the surface microlayer (50-60 microm) and subsurface layer (1m) of coastal waters. The presence of microplastics in sediments and seawater is likely due to on-going waste disposal practices from industries and recreational activities, and discharge from shipping.

A two-stage refinement approach for the enhancement of excretory production of an exoglucanase from Escherichia coli

Hyper-expression of a secretory exoglucanase, Exg, encoded by the cex gene of Cellulomonas fimi was previously shown to saturate the SecYEG pathway and result in dramatic cell death of recombinant Escherichia coli (Z.B. Fu, K.L. Ng, T.L. Lam, W.K.R. Wong, Cell death caused by hyper-expression of a secretory exoglucanase in Esherichia coli, Protein Expr. Purif. 42 (2005) 67-77). We propose here that the cell lysate ratio (Pre/Mat RQ) of the unprocessed precursor Exg protein (Pre-Exg) and its processed mature product (Mat-Exg) reflects the capacity of E. coli to secrete Exg. A Pre/Mat RQ of 20/80, designated the "Critical Value," was an important threshold measurement. A rise in the Pre/Mat RQ triggered a mass killing effect. The use of various secretion signal peptides did not improve the viability of cells expressing high levels of Pre-Exg under strong tac promoter control. However, use of the weaker vegG promoter in conjunction with a change in start codon of the spa leader sequence from ATG to TTG in a pM1vegGcexL plasmid construct resulted in a high level (0.9 U ml(-1)) of excreted Exg in shake-flask cultures. This was 50% higher than the best result obtained from plasmid construct lacUV5par8cex, using the lacUV5 promoter and the ompA leader sequence. Variations in the excreted Exg activities were attributable to differences in the Pre/Mat RQ values of the induced cultures harboring pM1vegGcexL and lacUV5par8cex. These values were 18/82 and 10/90, respectively. Employing fed-batch cultivation in two-liter fermentors, an induced JM101(pM1vegGcexL) culture yielded 4.5 U ml(-1) of excreted Exg, which was over six fold greater that previously reported. Our results illustrate the successful application of the Pre/Mat RQ ratio as a guide to the attainment of a maximum level of secreted/excreted Exg.

A Computer Model for Vibrating Conveyors

This paper presents the development of a computer model for predicting the performance of vibrating conveyors with reciprocating, circular or elliptical vibrating excitation. Experimental validation of the computer model for the reciprocating conveyor was carried out. The computer model takes into consideration all the three possible modes of motion (i.e. the throw mode, slide mode and stationary mode) and the transitions from one mode to another. It is based on a single particle mass analysis but using bulk material properties as the input, parameters. The predicted results are presented in non-dimensional plots. An experimental reciprocating vibrating conveyor with variable amplitude and frequency was constructed and tested with padi-rice and wet coal. Agreements between the theoretical and experimental results are good. Contour graphs derived from the non-dimensional plots of the reciprocating vibrating conveyor are also presented for design applications.

Cell death caused by hyper-expression of a secretory exoglucanase in Escherichia coli

Induced expression of a gene fusion between the ompA leader sequence and the Cellulomonas fimi cex gene encoding a secretory exoglucanase, Exg, engineered in the Tac-cassette excretion vector was lethal to Escherichia coli. An exponentially growing culture harboring the recombinant construct suffered slow growth and 99.9% of its cells died within 60-100 min after induction. This abnormality was found to have a close correlation with the rapid increase in the relative amount of the OmpA/Exg fusion precursor (Pre-Exg) compared to its processed product (Mat-Exg). Analysis of subcellular fractions revealed the presence of Pre-Exg in the inner membrane of cultures expressing high levels but not low levels of Pre-Exg. As only Pre-Exg but not Mat-Exg was detectable in the cytoplasm, and Exg was shown by cross-linking experiments to be physically associated with the Sec proteins, it was concluded that secretion and processing of Pre-Exg took place in the SecYEG translocation machinery. The results were in line with the previous speculation that accumulation of unprocessed precursor proteins in the cytoplasmic membrane was detrimental, and supported the idea that cell death was caused by some unusual tie-up of Pre-Exg with the SecYEG translocation machinery, thus imposing an inhibitory effect on the secretion of endogenous secretory proteins. A new model, designated "Saturated Translocation," was proposed to explain the interchangeable lethal and non-lethal properties of Pre-Exg, and to address the possible scenarios that might occur in the course of cell death triggered by secretion of Pre-Exg.

Novel growth hormone receptor mutation in a Chinese patient with Laron syndrome

Laron syndrome, growth hormone (GH) insensitivity syndrome, caused by a mutation of the GH receptor (GHR) gene, is extremely rare in the Chinese population. We report a Chinese girl diagnosed with Laron syndrome at age 1.9 years with height -4.9 SDS, basal GH 344 mIU/ml, IGF-I <12 ng/ml, IGFBP-3 <0.2 mg/ml, and undetectable GHBP. A novel mutation of the GHR, not previously described, was identified at the donor splice site of intron 6.

Application of a slow-release fertilizer for oil bioremediation in beach sediment

A 105-d field experiment was conducted to determine the potential of the slow-release fertilizer, Osmocote (Scotts, Marysville, OH), to stimulate the indigenous microbial biodegradation of petroleum hydrocarbons in an oil-spiked beach sediment on an intertidal foreshore in Singapore. Triplicate microcosms containing 80 kg of weathered sediment, spiked with 5% (w/w) Arabian light crude oil and 1.2% (w/w) Osmocote pellets, were established, together with control microcosms minus Osmocote. Relative to the control, the presence of the Osmocote sustained a significantly higher level of nutrients (NH(4)(+)-N, NO(3)(-)-N, and PO(4)(3-)-P) in the sediment pore water over the duration of the experiment. The metabolic activity of the indigenous microbial biomass, as measured using an intracellular dehydrogenase enzyme assay, was also significantly enhanced over the duration of the experiment in amended sediments. The loss of total recoverable petroleum hydrocarbons (TRPH) and biodegradation of total n-alkanes (C(10)-C(33)), branched alkanes (pristane and phytane), as well as total target polycyclic aromatic hydrocarbons (PAHs) (two- to six-ring), in both the control and Osmocote-amended sediments, followed a first-order biodegradation model. The first-order loss rate of total recoverable petroleum hydrocarbons was 2.57 times greater than that of the control. The hopane-normalized rate constants for total n-alkane, branched alkane, and total target PAH biodegradation in the Osmocote-treated sediments were 3.95-, 5.50-, and 2.45-fold higher than the control, respectively. Overall, the presence of Osmocote was able to significantly enhance and accelerate the biodegradation of aliphatics and PAHs in oil-contaminated sediments under natural field conditions in an intertidal foreshore environment.

Consensus statement on iodine deficiency disorders in Hong Kong

This article reviews the available data on the study of iodine deficiency disorders in Hong Kong and to discuss the approach towards preventing such disorders in Hong Kong. The importance of iodine and iodine deficiency disorders is described, and the available data on the dietary iodine intake and urinary iodine concentration in different populations of Hong Kong are summarised and discussed. Dietary iodine insufficiency among pregnant women in Hong Kong is associated with maternal goitrogenesis and hypothyroxinaemia as well as neonatal hypothyroidism. Borderline iodine deficiency exists in the expectant mothers in Hong Kong. Women of reproductive age, and pregnant and lactating women should be made aware and educated to have an adequate iodine intake, such as iodised salt, as an interim measure. A steering group involving all stakeholders should be formed to advise on the strategy of ensuring adequate iodine intake, including universal iodisation of salt in Hong Kong. Continuous surveillance of iodine status in the Hong Kong population is necessary.

Audit of investigations in patients with iron deficiency anaemia

BACKGROUND

Patients with iron deficiency anaemia (IDA) are commonly referred to the gastroenterologists for exclusion of gastrointestinal (GI) pathologies. The British Society of Gastroenterology (BSG) has published a guideline for management of IDA. As recommended by this guideline, all patients should have examinations of both upper and lower GI tract with the exception of pre-menopausal women younger than 45 years old. The primary aim of this audit was to determine how thoroughly patients referred to our unit at the Singapore General Hospital had been investigated. The secondary aim was to determine the yield rate of gastroscopy and lower gastrointestinal investigations (colonoscopy or barium enema) in our patients.

METHODS

We reviewed the case notes of patients who underwent gastroscopy for indication of anaemia between the period from April to December 1999. We classified iron deficiency anaemia as having haemoglobin of lower than reference range with either low ferritin level or iron/ TIBC ratio of less than 10%.

RESULTS

Of a total of 326 patients reviewed, 172 patients (65 men, 109 women) met the inclusion criteria of IDA. The median age for the group was 59 (Range 16 to 88) years old and there were 107 (62.2%) women. There were 31 female patients younger than 45 years old (group A) and 141 patients in group B which included all the males and females older than 45 years old. Due to the method of data retrieval, all of the patients in group A fulfilled the standard set by the BSG guideline in that they all underwent gastroscopy. In this group, few gastrointestinal pathologies were found (one patient with peptic ulcer and two patients with colonic cancer). In terms of finding potential gastrointestinal causes of IDA, the yield rate of gastroscopy and colonoscopy were 3.2% and 13.6% respectively. In group B, 96 patients (68%) underwent upper and lower gastrointestinal investigations. Evaluation with gastroscopy showed peptic ulcer disease in 31 patients (21.7%) and gastric cancer in 9 patients (6.3%). Only 96 patients (68.1%) in group B had lower gastrointestinal investigations. Twenty-six patients were found to have gastrointestinal disorders (12 patients with colon cancer, 10 colonic polyps, one Crohn's disease, one colonic tuberculosis and two haemorrhoids). The yield rate of gastroscopy and colonoscopy were 31.2% and 25% respectively.

CONCLUSION

In this study of patients with confirmed IDA, we found much higher incidence of gastrointestinal disorders in the group of male and postmenopausal women than in the group with premenopausal women. Furthermore, over 30% of patients in this group did not undergo lower gastrointestinal tract investigations as recommended by the BSG guideline. We also found two cases of colonic cancer in the latter group. We would recommend bidirectional endoscopy for postmenopausal women and men with IDA. For premenopausal women, we would recommend similar approach unless there are clinical pointers to dietary iron deficiency or menorrhagia.

Gastrointestinal Cytomegalovirus infection in non-human immunodeficiency virus infected patients

This is a retrospective study of fourteen patients who had proven Cytomegalovirus (CMV) infection of the gastrointestinal tract with no Human Immunodeficiency virus infection. The median age was 60.5 (Range 28 to 81) years. Eight patients were below (Group 1) and six above sixty five years old (Group 2). Areas of gastro-intestinal involvement were: oesophagus (2), stomach (1), colon (10) and multiple sites (1). Seven patients from Group 1 had received immunosuppressive therapy at the time of presentation and one had diabetes mellitus. We found a high prevalence of co-morbidities such as chronic renal failure and diabetes mellitus in Group 2. At median follow up of 13.9 months, there was a mortality rate of 50%. Only four patients were treated with ganciclovir. Our study concludes that the gastrointestinal CMV diseases in young patients were associated with immunosuppression whereas the older patients had chronic renal failure or diabetes.

Severe acute respiratory syndrome in children: experience in a regional hospital in Hong Kong

OBJECTIVE

To report the clinical, laboratory, and radiologic features of children with severe acute respiratory syndrome (SARS) and to examine the difference between the younger and older age groups.

DESIGN

Retrospective descriptive cohort study.

SETTING

A regional hospital in Hong Kong.

PATIENTS

Children younger than 18 yrs with SARS.

RESULTS

Twenty-one children were included, with a mean age of 10.7 +/- 5.1 yrs. Children with SARS presented with fever, nonproductive cough, malaise, chills, headache, myalgia, and loss of appetite. Examination of the chest showed minimal auscultatory findings. Common laboratory findings included lymphopenia, thrombocytopenia, and mild elevations of activated partial thromboplastin time, alanine transaminase, lactic dehydrogenase, and creatine phosphokinase. Bacteriologic and virologic studies were all negative for common pathogens. Unilateral focal opacity was the commonest finding in chest radiography. High-resolution computerized tomography of the thorax was an early diagnostic tool if the chest radiograph was negative. The clinical course was less severe in comparison with adult patients. However, adolescents (age, > or =12 yrs) resembled adults in their clinical features. When compared with the younger age group, the adolescents had significantly higher temperatures, more constitutional upset, and a greater need for steroid treatment. Children younger than 12 yrs seemed less ill but had more coughing. On the whole, the outcome was favorable.

CONCLUSION

Severe acute respiratory syndrome affects children, but the course is less severe. Nevertheless, the disease could have a significant psychosocial impact on children because of the potential seriousness of the disease in their adult family members.

Microwave drying of high strength dental stone: effects on dimensional accuracy

High-strength dental stone is widely used to produce dies for the fabrication of restorations with the lost-wax technique. It is normal to wait at least 24 hours for casts to dry and gain sufficient strength prior to initiating laboratory procedures. This waiting time may be greatly reduced by using microwave drying. This study determined the optimum microwave energy density for preserving working die accuracy of a Type IV high-strength dental stone (Silky Rock; Whipmix). Cylindrical die specimens were fabricated according to manufacturer's instructions and allowed to set for one hour. The specimens were subsequently treated as follows: Group I (Control group)--air dried; Group II--microwaved at 700W for 40 seconds; Group III--microwaved at 490W for 60 seconds. The percentage weight loss of cylindrical specimens (n = 6) and the percentage dimensional change (n = 7) of die specimens in three axes (x, y and z) were determined at 30 minutes, 1 hour and 24 hours after air drying/microwaving. Weight loss was measured using an electronic digital balance, while dimensional changes were assessed using image analysis software. Data was subject to ANOVA/Scheffe's tests at significance level 0.05. No significant difference in percentage weight loss was observed between air drying for 24 hours and microwaved specimens at all time intervals. Although no significant difference in percentage dimensional changes was observed between specimens microwaved at 490W for 60 seconds and specimens air dried for 24 hours, significant changes in x, y and z dimensions were observed after microwaving at 700W for 40 seconds at various time intervals. Microwave radiation at 490W for 60 seconds is recommended for drying Type IV high-strength dental stone. Further investigations are required to determine changes in physical properties associated with the aforementioned microwave power density.

Appendicitis following blunt abdominal trauma

A young boy presented with history of abdominal trauma. History and initial clinical findings suggested a soft tissue injury. Due to increasing abdominal pain and fever, we proceeded with an exploratory laparotomy with a diagnosis of intra-abdominal injury, at which we found a perforated appendix. Appendicitis following blunt abdominal trauma needs high index of suspicion.

Retention modelling of electrostatic and adsorption effects of aliphatic and aromatic carboxylic acids in ion-exclusion chromatography. II. Calculations of adsorption coefficients in unbuffered eluents

Previous models for the retention behaviour of carboxylic acids in ion-exclusion chromatography are applicable only when the degree of ionisation of the analyte is constant over the entire chromatographic peak. When solutions of sulfuric acid are used as eluents, this condition applies only when the eluent concentration is considerably higher than that of the analyte. Since it is common for dilute solutions of sulfuric acid to be used as eluents, a retention model which accounts for unbuffered eluents has been developed. This model also considers the effects on retention of hydrophobic adsorption of the undissociated and dissociated forms of the analyte onto the stationary phase substrate, as well as the effects of organic solvents added to the eluent. The derivation of this model is presented and it has been evaluated using a comprehensive set of retention data obtained using three different sulfonated stationary phases over a range of eluent conditions. The adsorption coefficients calculated from the model are in accordance with expected trends and showed that both the undissociated and dissociated forms of the analyte acids were retained by hydrophobic adsorption effects, although this adsorption was much stronger for the undissociated analytes.

Piezoelectric and pyroelectric properties of PZT/P(VDF-TrFE) composites with constituent phases poled in parallel or antiparallel directions

Composites of lead zirconate titanate (PZT) powder dispersed in a vinylidene fluoride-trifluoroethylene copolymer [P(VDF-TrFE)] matrix have been prepared by compression molding. Three groups of polarized samples have been prepared by poling: only the ceramic phase, the ceramic and polymer phases in parallel directions, and the two phases in antiparallel directions. The measured permittivities of the unpoled composites are consistent with the predictions of the Bruggeman model. The changes in the pyroelectric and piezoelectric coefficients of the poled composites with increasing ceramic volume fraction can be described by modified linear mixture rules. When the ceramic and copolymer phases are poled in the same direction, their pyroelectric activities reinforce while their piezoelectric activities partially cancel. However, when the ceramic and copolymer phases are poled in opposite directions, their piezoelectric activities reinforce while their pyroelectric activities partially cancel.

Pituitary-gonadal axis in male undermasculinisation

AIMS

To study the value of assessing serum concentrations of luteinising hormone (LH), follicle stimulating hormone (FSH), testosterone, and dihydrotestosterone (DHT) in patients with male undermasculinisation not caused by androgen insensitivity.

METHODS

A retrospective study of a register of cases of male undermasculinisation (20 with abnormal testes, eight with 5alpha-reductase deficiency, three with testosterone biosynthetic defects, seven with Drash syndrome, and 210 undiagnosed).

RESULTS

A human chorionic gonadotropin (hCG) stimulation test was performed in 66 of 185 children with male undermasculinisation. In 41 of 66 patients the dose of hCG was either 1000 U or 1500 U on three consecutive days. The rise in testosterone was related to basal serum testosterone and was not significantly different between the two groups. Testosterone:DHT ratio in patients with 5alpha-reductase deficiency was 12.5-72.8. During early infancy, baseline concentrations of LH and FSH were often within normal reference ranges. In patients with abnormal testes, median pre-LHRH (luteinising hormone releasing hormone) concentrations of LH and FSH were 2 and 6.4 U/l, respectively, and post-LHRH concentrations were 21 and 28 U/l. An exaggerated response to LHRH stimulation was observed during mid-childhood in children where the diagnosis was not clear and in all children with abnormal testes.

CONCLUSIONS

The testosterone:DHT ratio following hCG stimulation is more reliable than the basal testosterone:DHT ratio in identifying 5alpha-reductase deficiency. During infancy, the LHRH stimulation test may be more reliable in identifying cases of male undermasculinisation due to abnormal testes than basal gonadotrophin concentrations.

Retention modelling of electrostatic and adsorption effects of aliphatic and aromatic carboxylic acids in ion-exclusion chromatography

The retention mechanism of aliphatic and aromatic carboxylic acids in ion-exclusion chromatography has been investigated with consideration of simultaneous electrostatic repulsion effects and hydrophobic adsorption effects. A mathematical relationship between the retention factor of the analyte and the mobile-phase composition (sulfuric acid concentration and percentage of methanol), the type of analyte (pKa and hydrophobicity) and some physical characteristics of the stationary phase has been derived. Thirteen carboxylic acids (comprising mono- and divalent, aliphatic and aromatic acids) were chosen and used to acquire retention data on three different cation-exchange stationary phases (in which the sulfonate functional groups are bound to polystyrene-divinylbenzene, polymethacrylate or silica) using 14 mobile-phase compositions of varying pH and percent methanol. These retention data were used to derive the parameters necessary to solve the retention model using non-linear regression. In this way, a quantitative measure of the effects of adsorption phenomena on analyte retention were obtained. The model was then used to optimise the separation of nine carboxylic acids.

Effect of dietary macronutrients on food intake, body weight, and tail width in the marsupial S. crassicaudata

The role of dietary fat, as opposed to total energy intake, in the etiology of obesity is controversial. The aim of this study was to determine the effect of macronutrient content, specifically changes in dietary fat on body weight, fat stores, and food intake in S. crassicaudata, a marsupial that stores about 25% of total body fat in its tail. Female animals were divided into three groups (n = 7-9) matched for food intake per gram of body weight. Each group of animals was fed, ad lib an isocaloric diet (1.01 kcal/g), which contained either 10, 20, or 40% of calories from fat. Body weight, food intake, and tail width (an index of body fat stores) were measured daily. Over 21 days, cumulative energy intake was less (p = 0.026) in the 40% fat group compared to the 10% fat group. Despite the differences in food intake, body weight in each group remained stable throughout the study, so that at day 21 there were no differences in the body weights between the three groups. In contrast, tail width increased in the animals who received the 40% fat diet compared to either the 10% (p = 0.016) or 20% (p = 0.001) fat intake groups, whereas there was no significant change in tail width in either of these two groups. These observations indicate that macronutrient composition has a role, independent of total calories in the regulation of food intake and body fat stores, specifically that dietary fat promotes adiposity, independent of total caloric intake.