Supervised and induced sputum among patients with smear-negative pulmonary tuberculosis

Sputum culture is essential for monitoring drug resistance. Although sputum induction may optimise culture yield, better selection criteria and simpler algorithms are needed for countries with intermediate tuberculosis burdens. From a cohort of 660 patients who registered for antituberculosis treatment in a government chest clinic from May 21, 2005 to February 28, 2007, 187 patients with pulmonary disease and a negative smear in two unsupervised sputum specimens were enrolled prospectively for collection of one specimen each of supervised and induced sputum in succession. Among enrolled patients, induced sputum significantly improved ease of expectoration on a subjective five-point scale. Among 78 patients with culture-proven pulmonary tuberculosis, analysis of matched sputum culture results showed that: 1) induced sputum outperformed supervised sputum; 2) the second unsupervised sputum was significantly inferior to the first and redundant in the presence of the others; 3) adding one specimen each of supervised and induced sputum to two unsupervised specimens increased culture yield significantly; and 4) patients with either extent of disease less than right upper lobe or no respiratory symptoms were more likely to benefit. In summary, it may be practical to collect a sample of unsupervised, supervised and induced sputum for smear-negative patients with extent of disease less than the right upper lobe, especially when respiratory symptoms are absent.

Associations of functional candidate genes derived from gene-expression profiles of prenatal porcine muscle tissue with meat quality and muscle deposition

Ten genes (ANK1, bR10D1, CA3, EPOR, HMGA2, MYPN, NME1, PDGFRA, ERC1, TTN), whose candidacy for meat-quality and carcass traits arises from their differential expression in prenatal muscle development, were examined for association in 1700 performance-tested fattening pigs of commercial purebred and crossbred herds of Duroc, Pietrain, Pietrain x (Landrace x Large White), Duroc x (Landrace x Large White) as well as in an experimental F(2) population based on a reciprocal cross of Duroc and Pietrain. Comparative sequencing revealed polymorphic sites segregating across commercial breeds. Genetic mapping results corresponded to pre-existing assignments to porcine chromosomes or current human-porcine comparative maps. Nine of these genes showed association with meat-quality and carcass traits at a nominal P-value of < or = 0.05; PDGFRA revealed no association reaching the P < or = 0.05 threshold. In particular, HMGA2, CA3, EPOR, NME1 and TTN were associated with meat colour, pH and conductivity of loin 24 h postmortem; CA3 and MYPN exhibited association with ham weight and lean content (FOM) respectively at P-values of < 0.003 that correspond to false discovery rates of < 0.05. However, none of the genes showed significant associations for a particular trait across all populations. The study revealed statistical-genetic evidence for association of the functional candidate genes with traits related to meat quality and muscle deposition. The polymorphisms detected are not likely causal, but markers were identified that are in linkage disequilibrium with causal genetic variation within particular populations.

Five Interval Estimators for Proportion Ratio under a Stratified Randomized Clinical Trial with Noncompliance

It is not uncommon that we may encounter a randomized clinical trial (RCT) in which there are confounders which are needed to control and patients who do not comply with their assigned treatments. In this paper, we concentrate our attention on interval estimation of the proportion ratio (PR) of probabilities of response between two treatments in a stratified noncompliance RCT. We have developed and considered five asymptotic interval estimators for the PR, including the interval estimator using the weighted-least squares (WLS) estimator, the interval estimator using the Mantel-Haenszel type of weight, the interval estimator derived from Fieller's Theorem with the corresponding WLS optimal weight, the interval estimator derived from Fieller's Theorem with the randomization-based optimal weight, and the interval estimator based on a stratified two-sample proportion test with the optimal weight suggested elsewhere. To evaluate and compare the finite sample performance of these estimators, we apply Monte Carlo simulation to calculate the coverage probability and average length in a variety of situations. We discuss the limitation and usefulness for each of these interval estimators, as well as include a general guideline about which estimators may be used for given various situations.

Sample size determination for assessing equivalence based on proportion ratio under a randomized trial with non-compliance and missing outcomes

When a generic drug is developed, it is important to assess the equivalence of therapeutic efficacy between the new and the standard drugs. Although the number of publications on testing equivalence and its relevant sample size determination is numerous, the discussion on sample size determination for a desired power of detecting equivalence under a randomized clinical trial (RCT) with non-compliance and missing outcomes is limited. In this paper, we derive under the compound exclusion restriction model the maximum likelihood estimator (MLE) for the ratio of probabilities of response among compliers between two treatments in a RCT with both non-compliance and missing outcomes. Using the MLE with the logarithmic transformation, we develop an asymptotic test procedure for assessing equivalence and find that this test procedure can perform well with respect to type I error based on Monte Carlo simulation. We further develop a sample size calculation formula for a desired power of detecting equivalence at a nominal alpha-level. To evaluate the accuracy of the sample size calculation formula, we apply Monte Carlo simulation again to calculate the simulated power of the proposed test procedure corresponding to the resulting sample size for a desired power of 80 per cent at 0.05 level in a variety of situations. We also include a discussion on determining the optimal ratio of sample size allocation subject to a desired power to minimize a linear cost function and provide a sensitivity analysis of the sample size formula developed here under an alterative model with missing at random.

Standard anti-tuberculosis treatment and hepatotoxicity: do dosing schedules matter?

A nested case-control study was conducted in order to examine whether dosing schedules of standard pyrazinamide-containing anti-tuberculosis (TB) treatment (standard treatment) might affect hepatotoxicity. The present authors retrospectively identified all patients with hepatitis using biochemical criteria from a cohort of 3,007 clinic patients who commenced anti-TB treatment from January 1 to June 30, 2001. Each case with hepatitis between 1-9 weeks post-TB treatment was compared using conditional logistic regression analysis with two controls selected randomly from patients without hepatitis in the same period and matched by sex, age and standard treatment. Impacts of sex and age were examined by logistic regression analysis of cases and patients without hepatitis. Hepatitis occurred in 167 patients, of whom 96 qualified as cases. A conditional logistic risk model identified hepatitis B surface antigen carriage as the only risk factor (odds ratio (95% confidence interval (CI)) 1.8 (1.1-3.1)). Logistic regression analysis showed that sex was nonsignificant but ageing increased the odds of hepatitis. The risk of hepatitis increased from 2.6% (1.9-3.5%) to 4.1% (3.2-5.3%) as age exceeded 49 yrs. Dosing schedules in the first 9 weeks have little impact on hepatotoxicity. If patients at risk of both hepatitis and relapse receive standard treatment, daily dosing is preferable.

Inherited myopathy of great Danes

A hereditary, non-inflammatory myopathy occurring in young great Danes with distinctive histological features in muscle biopsy specimens is reviewed. Onset of clinical signs is usually before one year of age and both sexes are affected. Clinical signs are characterised by exercise intolerance, muscle wasting, and an exercise-induced tremor. Although most affected dogs have a severe form of the disease, occasional dogs may have a less pronounced form and survive into adulthood with an acceptable quality of life. Litters containing affected puppies are born to clinically unaffected parents, and an autosomal recessive pattern of inheritance is likely. All recorded cases have had fawn or brindle coat coloration. Elevated serum creatinine kinase concentrations and spontaneous electrical activity in skeletal muscles are frequently found. While originally reported (Targett and others 1994) as a central core myopathy in this breed, the histochemical characteristics of the distinct cytoarchitectural structures differ from those of the well-characterised central core myopathy in human beings. In fact, these structures differ from any known myopathy in human beings and likely represents a unique non-inflammatory myopathy affecting dogs. Until this myopathy is characterised further, the name inherited myopathy in great Danes is suggested.

Phorbol ester up-regulates aldose reductase expression in A549 cells: a potential role for aldose reductase in cell cycle modulation

Over-expression of aldose reductase (AR) has been observed in many cancer cells. To clarify the role of AR in tumor cells, we investigated the pathways mediating expression of the AR gene induced by 12-O-tetradecanoylphorbol-13-acetate (TPA), a potent tumor promoter. In A549 human lung adenocarcinoma cells, TPA elicited a dose- and time-dependent increase in AR mRNA level with an elevated enzyme activity. The TPA-induced increase in mRNA level and promoter activity of the AR gene was significantly attenuated in the presence of an inhibitor of protein kinase C, tyrosine kinase, or nuclear factor kappaB (NF-kappaB). TPA augmented the NF-kappaB-dependent gene transcription, indicating the involvement of NF-kappaB in this regulation. Accumulation of TPA-treated cells in S phase was almost completely abolished in the presence of ethyl 1-benzyl-3-hydroxy-2(5H)-oxopyrrole-4-carboxylate, an AR inhibitor. Taken together, TPA augmented the promoter activity of the AR gene via the activation of protein kinase and NF-kappaB. The inhibition of AR may assist in the chemotherapy of malignant tumors by suppressing the rapid growth of cancer cells.

Tuberculin response in BCG vaccinated schoolchildren and the estimation of annual risk of infection in Hong Kong

BACKGROUND

In Hong Kong there has been nearly universal neonatal BCG vaccination coverage since 1980.

METHOD

21 113 schoolchildren aged 6-9 years were skin tested with one unit of tuberculin (PPD RT-23) using the intradermal technique during a routine BCG revaccination programme. Information on sex, date of birth, date of tuberculin testing, and tuberculin reaction size at 72 hours was retrieved. The annual risk of tuberculous infection (ARTI) was estimated by three different approaches.

RESULTS

Significantly higher tuberculin positive rates were found in girls and with increasing age at all commonly used cut-off points (5, 10, and 15 mm). Using a cut-off point of > or =10 mm and the formula 1- (1 - tuberculin positive rate)(1/age), the ARTI was estimated to be 1.93% (95% CI 1.84 to 2.03) for girls and 1.41% (95% CI 1.33 to 1.50) for boys. Using the differences in the tuberculin positive rate between the 6-7 year and 8-9 year age groups, the ARTI became 1.90% (95% CI 1.09 to 2.70) and 1.84% (95% CI 1.15 to 2.54) for girls and boys, respectively. When the prevalence of infection was estimated by locating a secondary peak of the tuberculin reaction distribution curve at 15 mm and assuming a symmetrical distribution of reaction sizes among those infected around this peak, the corresponding ARTI was much lower at 0.52% (95% CI 0.46 to 0.59) and 0.43% (95% CI 0.37 to 0.49) for girls and boys, similar to that estimated indirectly from the prevalence of disease.

CONCLUSION

The ARTI as estimated by conventional methods was unexpectedly high among BCG vaccinated children and did not agree with that anticipated from the annual incidence of active disease. Further studies are needed to address the discrepancies, including the possible interaction between BCG and other environmental stimuli.

Structural characteristics of purified beta-conglycinin from soybeans stored under four conditions

Four storage conditions including adverse conditions [84% relative humidity (RH), 30 degrees C], mild conditions (57% RH, 20 degrees C), cold conditions (4 degrees C), and uncontrolled ambient conditions were used for storing soybeans. The storage time was 9 months for the adverse conditions and 18 months for the other three conditions. Beta-conglycinin was purified and characterized with respect to its molecular properties. After storage under the adverse conditions, beta-conglycinin showed no significant changes in total sugar content, surface hydrophobicity, free SH and SS bonds, and amino acid composition within 6 months; however, it showed a significant decrease in surface hydrophobicity and a significant increase in total free SH and total SH including SS content after 6 months. Analysis of the secondary structure showed a significant increase in alpha-helix content, but a significant decrease in beta-sheet content after 3 months. For the other three conditions, no significant changes occurred to the structures of beta-conglycinin when compared to the control. The molecular mass of beta-conglycinin remained in the range of 199-212 kDa for all conditions during the entire storage periods.

Risk factors for defaulting from anti-tuberculosis treatment under directly observed treatment in Hong Kong

OBJECTIVE

To identify risk factors for defaulting from anti-tuberculosis treatment.

SETTING

Directly observed treatment in Hong Kong Government chest clinics.

DESIGN

Defaulters were recruited from a cohort of tuberculosis patients registered from 1 January to 31 March 1999. Three controls per case, matched for age and sex, were selected randomly from the cohort. Patient factors, initial tuberculosis characteristics and treatment-related variables were collected by review of medical records.

RESULTS

On matching 102 defaulters and 306 controls, a logistic risk model of default that considered patient factors, initial disease characteristics and treatment-related factors identified seven risk factors: current smoking (OR 3.00, 95% CI 1.41-6.39), past TB with default (OR 6.23, 95% CI 1.95-19.91), poor initial adherence (OR 117.21, 95% CI 13.52-1015.92), fair initial adherence (OR 11.02, 95% CI 2.15-56.43), unknown initial adherence (OR 6.59, 95% CI 3.47-12.49), treatment side effects (OR 13.30, 95% CI 3.23-54.79), and subsequent hospitalisation (OR 0.27, 95% CI 0.11-0.67). Its predictive power was 85%. Another model that considered only factors on registration for treatment gave a lower predictive power of 70%.

CONCLUSIONS

Treatment default could be predicted fairly accurately by considering patient and treatment-related factors.

Cluster characterisation and temporal expression of porcine sarcomeric myosin heavy chain genes

Members of the myosin heavy chain (MyHC) gene family are subjected to temporal regulation of gene switching during development. One strategy to the identification of cis-acting regulatory elements that are involved in temporal or fibre-type specific regulation is to undertake a comparative analysis of the MyHC gene family between the pig, an important target species, and other mammals, like human whose entire genome has been recently sequenced. Towards this end, we report here on the isolation, and characterisation of the porcine cardiac (MyHC slow/beta and alpha) and skeletal MyHC (embryonic, 2a, 2x, 2b and perinatal) gene clusters, and their structural comparisons with mouse and human clusters. The genome organisation of both clusters in the pig, human and mouse is conserved as having the same gene order, similar intergenic distances, and in the same head-to-tail orientation. For a period of pre-natal muscle growth, relative expression of MyHC isoforms, as determined by TaqMan real-time RT-PCR, correlated with the gene order in the skeletal MyHC cluster (embryonic > 2a > 2x > 2b) suggesting the possible presence of DNA elements on the same side as the MyHC embryonic gene that direct temporal regulation.

Socio-economic factors and tuberculosis: a district-based ecological analysis in Hong Kong

BACKGROUND

Relatively little is known about the impact of socio-economic factors on tuberculosis in a metropolitan city with high disease incidence.

METHOD

District-specific tuberculosis notification rates for 1995--1997 and 2000--2002 were indirectly sex- and age-adjusted and compared with the socio-economic characteristics in the 1996 by-census and 2001 census.

RESULTS

The differences between the 18 districts persisted after 3-year averaging and indirect standardisation. Only the percentage of population born locally, the percentage of the population widowed or divorced and the percentage of households residing in rooms or bedsits were consistently associated with the standardised notification ratios (SNR) for both periods, the first being negatively so (all P < 0.05). In a combined analysis with a general linear model for both periods, birth in China, residence <7 years, speaking other Asian languages, being married and in a single household were also significantly associated with the SNR (all P < 0.05). Using a backward conditional approach, only local birth, being married, and residing in rooms or bedsits were independent predictors of SNR (all P < 0.05). There was no significant association between SNR and socio-economic indices on education, occupation, unemployment and income.

CONCLUSION

Socio-economic factors other than simple poverty are affecting the district-specific tuberculosis rates in Hong Kong.

Smoking and tuberculosis in Hong Kong

OBJECTIVE

To study the relationship between smoking and tuberculosis in Hong Kong.

METHOD

Indirect sex and age adjustment was used to compare the prevalence of ever smokers between a sample of 851 patients from the 1996 tuberculosis notification registry and the general population. The clinical characteristics of smokers and non-smokers were compared by stratified univariate analysis and multiple logistic regression.

RESULTS

Tuberculosis patients were more likely to have smoked than population controls. The respective odds ratios for ever smoking between tuberculosis patients and population controls were 2.44 and 2.08 for males and females aged 16-64 (Mantel-Haenszel weighted OR = 2.40, P < 0.001), and 2.09 and 2.83 for males and females aged > or = 65 (Mantel-Haenszel weighted odds ratio = 2.19, P < 0.001). Male sex, age > or = 65, working at onset of illness, regular alcohol use, drug abuse and absence of contact history were associated with ever smokers (all P < 0.05). Ever smokers were more likely to have cough (OR 1.69), dyspnoea (OR 1.84), upper zone involvement (OR 1.67), cavity (OR 1.76), miliary lung involvement (OR 2.77), positive sputum culture (OR 1.43), but less isolated extrathoracic involvement (OR 0.31), even after controlling for the confounding background variables (all P < 0.05).

CONCLUSION

There was a consistent association between smoking and tuberculosis. More aggressive lung involvement was also found among ever smokers.

Development of a rapid titration method for predicting optimal coagulant concentration for filled tofu

A rapid titration method was developed for predicting the optimal coagulant concentration for making filled tofu. Cooked soymilk (350 mL, 20 degrees C) in a 400 mL beaker was stirred by a magnetic stirrer to form a swirl. The quick-acting coagulant solution (20.0 Brix) was added into the soymilk at 1.0 mL/min. The swirl depth decreased when the soymilk viscosity increased as a result of increasing the concentration of coagulant in the soymilk. At a suitable stirrer speed, the swirl finally disappeared but the soymilk still maintained rotation, and then the swirl reappeared after around 1 min. The critical point of coagulant concentration (CPCC) was calculated on the basis of the volume of coagulant consumed to get the swirl to disappear. The influences of several factors on the CPCC were investigated, including coagulant addition rate, soymilk temperature, soymilk concentration, soymilk volume, stir bar length, and container size. For validation, 33 soybean samples were used to determine their CPCCs and make filled tofus. The results indicated that CPCC was a characteristic parameter of soymilk and could be used as an effective indicator for predicting optimal coagulant concentration.

Identification of microsatellites in expressed muscle genes: assessment of a desmin (CT) dinucleotide repeat as a marker for meat quality

We investigated the presence of dinucleotide repeats (microsatellites) in a porcine skeletal muscle cDNA library. In total, microsatellites were found in nearly 4% of all muscle cDNA clones, of which CT- and TG-repeats were the most prevalent. We found a near full-length desmin cDNA clone with a CT-repeat sited downstream from its stop codon. From 44 commercially reared pigs, six allelic length polymorphisms were identified at this microsatellite locus (128, 131, 134, 135, 136, and 138 bp), whose desmin genotypes were associated with pH change after slaughter (P=0.031) and colour variation of meat (P<0.001 for hue, P<0.005 for lightness, and P=0.014 for b colour). Two of the genotypes (131/131 bp and 131/135 bp) were consistent with paler meat. This finding indicates the usefulness of the cDNA library approach to generate markers for marker-assisted selection and suggests that the desmin microsatellite could be a possible selection marker.

Molecular and quantitative characterisation of the porcine embryonic myosin heavy chain gene

The porcine embryonic myosin heavy chain (MyHC) is a major isoform in foetal skeletal muscle, and is the last remaining major porcine skeletal MyHC gene to be isolated and characterised. We report here on its cDNA and genomic isolation, molecular characterisation, quantification and expression. Unlike all other porcine and mammalian skeletal MyHC genes reported to date, the deduced translated start site of the porcine embryonic gene was located in exon 2, instead of exon 3. Its promoter conferred differentiation-specific expression. We found, by quantitative real-time RT-PCR, that for much of gestation the embryonic MyHC was by far the most transcriptionally active gene compared with the slow/I and perinatal MyHC isoforms, and it was consistently more highly expressed than the perinatal isoform throughout gestation. The embryonic MyHC isoform was, however, rapidly down-regulated at around birth. By contrast, 22 weeks after birth, the porcine perinatal isoform remained detectable by PCR. Additionally, we discovered the presence of differential splicing at the 3'-end of the embryonic MyHC gene that resulted in an in-frame deletion, with the consequential loss of 93 amino acids close to the ACD domain, a region that is important for the assembly of myosin filaments. The detection of this truncated variant points to a possible major post-transcriptional mechanism of embryonic MyHC regulation that may be linked to myosin filament formation or turnover.

Extracranial head and neck schwannomas: a review of 8 years experience

Schwannomas of the head and neck are uncommon tumors that arise from cranial, peripheral or autonomic nerves. In this study we review a series of 52 cases of schwannoma originating in the head and neck region over an 8-year period. All the tumors were benign, with the exception of one malignant schwannoma. The age range of the patients studied was 13-76 years and there was a predilection for males. Twenty-five schwannomas occurred in the scalp, face and external ear canal, 9 in the oral or nasal cavity and 18 in the neck. Seven cases of neck schwannoma originating from the major nerve system were found in the parapharyngeal space, all of which were located in the post-styloid compartment. Cervical plexus schwannomas originated either in the peripheral nerves or in an unidentified area of the nervous system; seven tumors were found in the posterior triangle of the neck and two in the anterior triangle. Two of the tumors originating in the brachial plexus were located in the posterior neck and one in the anterior neck. Tumors originating in the vagus nerve or sympathetic chain were all located in the anterior triangle of the neck.

Respiratory insufficiency in a Chinese adult with mitochondrial myopathy

Mitochondrial myopathy is an important but uncommon cause of respiratory insufficiency in adults. We report the first case of respiratory insufficiency associated with adult-onset mitochondrial myopathy seen in a Chinese adult in Hong Kong. The patient presented with peripheral oedema and shortness of breath over 2 to 3 days. There was a history of gradual progressive limb weakness over approximately 2 years, hypertrophic cardiomyopathy, intermittent diarrhoea, and weight loss. The diagnosis was made by skeletal muscle biopsy and molecular study, which revealed the A3243G point mutation.

Hypotensive effects of captopril on physical properties of the arterial system in young and adult rats

We determined the acute effects of the angiotension converting enzyme inhibitor captopril on the arterial mechanics in rats at different ages, based on the exponentially tapered T-tube model. Male Wistar-Kyoto rats aged 4 and 12 months were individually referred to as young (n = 8) and adult rats (n = 8) and were anesthetized and thoractomized. The pulsatile aortic pressure and flow signals before and after the administration of captopril (20 mg/kg, i.p.) were measured by a high-fidelity pressure sensor and an electromagnetic flow probe, respectively. In each age group, captopril showed little change in basal heart rate as well as cardiac output. However, captopril produced a drop of 15% in mean aortic pressure in young and a fall of 12% in adult rats. In addition. captopril reduced total peripheral resistance by 21% in young and by 23% in adult animals. As for the pulsatile nature of the arterial system, captopril had increased wave transit time of the lower body circulation of 10% in young and of 12% in adult rats. By contrast, captopril reduced wave reflection factor by 22% in young and by 25% in adult animals. In conclusion, the converting enzyme inhibitor captopril has a stiffness-decreasing effect on Windkessel vessels and a dilated effect on resistance arterioles in either young or adult rats. No age dependence of vascular response and reflex tachycardia to captopril has been found in rats between 4 and 12 months.