Multimodal Data Integration to Predict Severe Acute Oral Mucositis of Nasopharyngeal Carcinoma Patients Following Radiation Therapy

(1) Background: Acute oral mucositis is the most common side effect for nasopharyngeal carcinoma patients receiving radiotherapy. Improper or delayed intervention to severe AOM could degrade the quality of life or survival for NPC patients. An effective prediction method for severe AOM is needed for the individualized management of NPC patients in the era of personalized medicine. (2) Methods: A total of 242 biopsy-proven NPC patients were retrospectively recruited in this study. Radiomics features were extracted from contrast-enhanced CT (CECT), contrast-enhanced T1-weighted (cT1WI), and T2-weighted (T2WI) images in the primary tumor and tumor-related area. Dosiomics features were extracted from 2D or 3D dose-volume histograms (DVH). Multiple models were established with single and integrated data. The dataset was randomized into training and test sets at a ratio of 7:3 with 10-fold cross-validation. (3) Results: The best-performing model using Gaussian Naive Bayes (GNB) (mean validation AUC = 0.81 ± 0.10) was established with integrated radiomics and dosiomics data. The GNB radiomics and dosiomics models yielded mean validation AUC of 0.6 ± 0.20 and 0.69 ± 0.14, respectively. (4) Conclusions: Integrating radiomics and dosiomics data from the primary tumor area could generate the best-performing model for severe AOM prediction.

A pilot external quality assurance programme for line-probe assay detection of anti-tuberculosis drug resistance

BACKGROUND

Multidrug-resistant tuberculosis (MDR-TB; resistance to isoniazid and rifampicin) is difficult to detect and control. Line-probe assays (LiPA) are widely used for the rapid detection of MDR-TB.

OBJECTIVE

To ensure the quality of the test, a pilot external quality assurance (EQA) programme was initiated to assess the feasibility of running such a programme and the possibility of improving the proficiency of TB laboratories in performing the test.

DESIGN

Prepared filter-paper-based Mycobacterium tuberculosis DNA samples were shipped to participant laboratories for LiPA EQA. The tests were performed blind, and the results were returned to the organising laboratory for comparison and analysis.

RESULTS

A total of four rounds of EQA samples were dispatched to five laboratories in four countries. Overall inter- and intra-laboratory reproducibility was respectively 97% and 96%. The strengths and weaknesses of the participant laboratories in performing the test were discussed.

CONCLUSION

A LiPA EQA programme can ensure quality and improve the performance of TB laboratories. This is a critical step during the initial stages at the time of setting up this method of testing.

Random blinded rechecking of sputum acid-fast bacilli smear using fluorescence microscopy: 8 years' experience

BACKGROUND

The Hong Kong TB Reference Laboratory is a high volume laboratory examining around 400 sputum acid-fast bacilli smears daily using fluorescence microscopy (FM).

OBJECTIVE

To assess the effectiveness of blinded rechecking applied to FM in a high-throughput laboratory.

METHOD

From 2003, 2.5% (5% in 2003 and 2004) of all smears were randomly selected, relabelled and assigned to each technician (rechecker) in turn. These smears were restained and re-examined. Discordance between initial screener and rechecker was resolved by a controller.

RESULTS

From 2003 to 2010, low false-negative (LFN) errors (0.10-0.27%) were within the critical values, at 85% (1 year) and 90% (7 years) sensitivity. However, LFN error (0.28-0.62%) among recheckers was prominent. There were also low false-positive (LFP) cases (0.13-0.75%), but subsequent cultures showed these to be mycobacteria culture-positive. This relatively poor performance among the recheckers might be due to background fluorescence increase after restaining and/or inefficiency of the rechecking procedure.

CONCLUSION

In a high-throughput laboratory, blind rechecking is a good means of quality assurance. To minimise false LFP, problems due to restaining should be resolved before blinded rechecking can be generally applied in the field for FM where mycobacterial cultures are not routinely performed.

A prospective pilot study of repetitive transcranial magnetic stimulation for gait dysfunction in vascular parkinsonism

OBJECTIVE

Vascular Parkinsonism (VP) causes significant gait dysfunction in patients who otherwise have good lower limb strength. Its pathophysiology is not clearly understood, and current treatment with physical therapy remains unsatisfactory. The study explores repetitive transcranial magnetic stimulation (rTMS) as a potential new and safe therapy for VP.

MATERIALS AND METHODS

We prospectively applied 5 Hz rTMS treatment to 5 patients who satisfied all the criteria for VP. Repetitive TMS was performed on 5 consecutive days and patients were assessed on (1) timed 10 m walk (T10MW), (2) Unified Parkinson's Disease Rating Scale (UPDRS) motor subsection, (3) Clinician's Global Impression of Change (CGIC), and (4) Patient's Global Impression of Change (PGIC), for up to 6 weeks post-rTMS.

RESULTS

All the outcome measures were found to have improved ratings post-rTMS when compared with baseline, and were statistically significant. The T10MW showed significant improvement at 4 weeks post-rTMS with a trend towards improvement at 2 weeks post-rTMS. The UPDRS motor subscores was significantly reduced at 2 weeks, 4 weeks and 6 weeks post-rTMS. The PGIC and CGIC scores were significantly better post-rTMS. The treatment was well-tolerated and all patients completed the study.

CONCLUSION

This study demonstrated for the first time that 5 sessions of rTMS could improve gait in a measurable way for up to 6 weeks without any significant side-effects. Repetitive TMS could be a potentially useful adjunct in rehabilitation of VP patients and further research is warranted.

Usefulness of resistant gene markers for predicting treatment outcome on second-line anti-tuberculosis drugs

AIM

Mutations in rrs [nucleotide (nt) 1401], gyrA gene (codons 90, 91 or 94), tlyA, ethA and thyA genes of Mycobacterium tuberculosis (MTB) were evaluated for their usefulness in predicting treatment outcome of kanamycin (KM), capreomycin (CPM), ofloxacin (OFX), ethionamide (ETH) and para-aminosalicylic acid (PAS).

METHODS AND RESULTS

DNA sequence analyses of these genes were performed against 188 MTB isolates obtained from patients put on second-line anti-TB drugs (SLDs) with well-documented clinical history and treatment outcome. Mutations in rrs and gyrA have 100% positive predictive value (PPV) in predicting treatment failure for KM and OFX, while 88·9 and 80% were obtained, respectively, when tlyA and rrs mutations were considered in CPM. For ETH and PAS, the PPV of using ethA and thyA mutations to predict treatment failure was 82·5 and 89·3%, respectively.

CONCLUSIONS

Our study demonstrated high specificities of gene mutations in predicting poor treatment outcome; however, further technical advancement is required to make the molecular detection of resistances to other SLDs feasible in clinical laboratories.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first study to correlate different polymorphisms of major SLD resistance gene markers with predicted treatment outcome, using an international set of well-documented clinical MTB strains.

Determination of critical concentrations of second-line anti-tuberculosis drugs with clinical and microbiological relevance

BACKGROUND

Reliable DST against second-line anti-tuberculosis drugs (SLDs) is crucial for the management of the increasing burden of patients affected by multidrug- and extensively drug-resistant TB.

METHODS

This study utilizes 252 clinical isolates of Mycobacterium tuberculosis from five countries (Hong Kong Special Administrative Region, Korea, Latvia, Peru, Philippines) with documented treatment histories to establish clinically and microbiologically relevant critical concentrations (CCs) of six SLDs for three routine testing methods: the absolute concentration method using Löwenstein-Jensen (LJ) medium, the 1% proportion method using Middlebrook 7H10 agar medium, and the radiometric BACTEC 460 system.

FINDINGS

In LJ medium, CCs of capreomycin, ethionamide, kanamycin, ofloxacin, rho-aminosalicylic acid and cycloserine (CS) were respectively 40.0, 40.0, 30.0, 3.0, 1.0 and 30.0 mg/l. In 7H10 agar medium, the respective CCs for the first five antibiotics (except CS) were 8.0, 2.0-3.0, 3.0-5.0, 1.0-1.5 and 0.5-1.0 mg/l. In BACTEC 460 broth, the respective CCs were 1.5-2.0, 1.0-1.5, 2.0-3.0, 0.5-1.0 and 0.5-1.0 mg/l. Precautions in DST interpretation was also discussed.

INTERPRETATION

By adopting this set of CCs as a global standard to define second-line drug susceptibility and resistance, as well as precautions in result interpretation, the screening, diagnosis and management of patients with drug-resistant TB can be greatly improved.

Bulk acid-fast staining of sputum smears: time to end a taboo

SETTING

A high-throughput laboratory routinely performing fluorescence microscopy for acid-fast bacilli (AFB) smear with automated bulk staining.

OBJECTIVES

To determine the risk of false-positive AFB sputum smears from bulk staining showing as smear-positive, culture-negative specimens, or a decrease in smear- and culture-positives.

DESIGN

Direct AFB smear and Löwenstein-Jensen culture were performed for a total of 39,350 routine sputum specimens. Of these, 6633 were randomly selected for individual AFB staining, while the remaining 32,717 were processed by bulk machine staining. Positives for smear and culture were compared.

RESULTS

Overall, 111 specimens yielded a positive individually stained smear; of these, 100 (90.1%, 95%CI 83.0-95.0) were also culture-positive compared to 504/543 smear-positives after bulk staining (92.8%, 95%CI 90.6-95.0). The proportions of smear-positive, culture-negative and smear- and culture-positive specimens were respectively 1.8% vs. 2.2% and 90.1% vs. 92.8%, for individual and bulk staining (non-significant).

CONCLUSIONS

The risk of transferring AFB from positive to negative smears during bulk AFB staining is negligible, if it occurs at all. Bulk staining should not be discouraged, as even in low-income countries this method will save significant resources, particularly manpower, and improve staining results in laboratories with a high workload.

Variations in quality of carbol fuchsin stains collected from routine tuberculosis laboratories

SETTING

In-use carbol fuchsin stains were collected from 10 different routine acid-fast bacilli smear microscopy laboratories.

OBJECTIVE

To examine the variations in the composition of carbol fuchsin stains.

METHOD

Carbol fuchsin concentrations were first determined spectrophotometrically by measuring absorbance at 547 nm. High-performance liquid chromatography (HPLC) separated and quantified the four basic fuchsin homologues: para-rosaniline, rosaniline, magenta II and new fuchsin, and identity was confirmed by mass spectrometry (MS).

RESULTS

Absorbance measurement showed that three of 10 (30%) samples contained insufficient carbol fuchsin (<70%). Wide variations in relative proportions of fuchsin homologues were found.

CONCLUSION

The relative abundance of rosaniline + new fuchsin was quite stable among the different laboratories. Spectrophotometry and HPLC/MS are necessary and sensitive tools for monitoring fuchsin quality.

Cloning and characterization of chicken growth hormone binding protein (cGHBP)

Growth hormone (GH) is indispensable for the growth of animals and its biological activity is mediated by binding to the growth hormone receptor (GHR) [Harvey S, Scanes CG, Daughaday WH. Growth hormone. Boca Raton: CRC Press; 1995]. GHR is a transmembrane protein responsible for signal transduction upon GH binding. GH also binds to the growth hormone binding protein (GHBP) which is the soluble form of GHR extracellular domain existing in circulation. Actions of GHBP include prolongation of GH bioavailability and prevention of GH signaling system from over-stimulation. To date, little is known about the mechanisms generating the chicken GHBP (cGHBP). Elucidating the genomic structure of cGHR will provide insights into such underlying mechanisms. Using polymerase chain reaction and library screening methods, we have characterized the genomic organization of chicken GHR (cGHR). The full-length coding region of the cGHR transcript is composed of eight exons (exons 2-10), lacking a human homolog exon 3 and spans at least 71 kb on the genome. A novel transcript of size 1.2kb was isolated from chicken liver total RNA using 5' and 3' rapid cDNA ends amplification (RACE). It was generated by utilizing a previously unknown polyadenylation signal located at the intron 6. Semi-quantitative reverse transcription polymerase chain reaction showed that this transcript is widely expressed in a variety of tissues. This transcript has an open reading frame comprising 203 amino acids. In vitro binding assay using ELISA demonstrated that Escherichia coli expressed recombinant protein encoded by this transcript was able to bind with chicken GH. Hence, this transcript is a potential candidate for cGHBP.

Severe leptospirosis with unusual manifestation

We report a case of an 8-year-old aborigine boy referred to our hospital for respiratory insufficiency with skin eruptions over the trunk and limbs. The skin condition was diagnosed as acquired ichthyosis. He also had a non-bleeding form of disseminated intravascular coagulopathy. Radiograph of the lungs showed bilateral perihilar opacities with bilateral pleural effusion. The diagnosis of leptospirosis was confirmed by a 4-fold rise in microagglutinating titre and polymerase chain reaction assay.

An abdominal mass owing to Penicillium marneffei in an HIV-infected 7-year-old boy: case report

A 7-year-old boy, referred with lymphoma, presented with prolonged fever and intra-abdominal lymphadenopathy demonstrated on computed tomography (CT) of the abdomen. Blood culture isolated Penicillium marneffei. The patient was subsequently proven serologically to be positive for human immunodeficiency virus (HIV). Treatment with amphotericin B followed by itraconazole was successful. A high level of clinical suspicion and awareness is necessary for early diagnosis of penicilliosis, especially in an era of an increasing prevalence of HIV in this region.

Denaturing HPLC for high-throughput screening of rifampicin-resistant Mycobacterium tuberculosis isolates

OBJECTIVE

To evaluate the use of denaturation high-performance liquid chromatography (dHPLC) as a rapid method to detect rifampicin (RMP) resistance based on mutations in the rpoB gene in a high-volume laboratory setting.

METHODS

A total of 132 RMP-resistant Mycobacterium tuberculosis strains with different rpoB mutation were used to optimise the running condition of dHPLC as a pilot study. A blind correlation study was subsequently done between dHPLC and in vitro RMP susceptibility tests on 3167 M. tuberculosis strains in a high-throughput clinical setting.

RESULTS

In the pilot study, rpoB mutation could be detected on 116/132 (87.9%) RMP-resistant strains by dHPLC. In the second phase of the study, 84/3107 (2.7%) clinical M. tuberculosis isolates were RMP-resistant. The sensitivity and specificity of dHPLC in the prediction of RMP resistance were 70/84 (83.3%) and 70/77 (91.0%), respectively. The specificity became 100% when 511 Leu to Pro mutation was excluded from the RMP resistance-related genetic changes.

CONCLUSION

In the detection of RMP resistance in a high-throughput laboratory setting, dHPLC has been demonstrated to be rapid, simple, workable, automatable and inexpensive in terms of running costs and the labour involved.

Mycoplasma pneumoniae infection complicated by empyema: a rare presentation

Mycoplasma pneumoniae is a common causative agent for childhood pneumonia. However, empyema is a rare presentation. We report a case of a previously well child who presented with a right-sided empyema. M. pneumoniae was confirmed serologically with evidence of a four-fold rise in Mycoplasma IgM titre. The empyema required drainage procedures for more than two weeks. The infection resolved with a course of six weeks of treatment with erythromycin.

Surveillance of Mycobacterium tuberculosis susceptibility to second-line drugs in Hong Kong, 1995-2002, after the implementation of DOTS-plus

OBJECTIVE

To determine the trend in changes in susceptibility of Mycobacterium tuberculosis strains, including to second-line drugs, from patients with a history of previous anti-tuberculosis (TB) treatment in a 'DOTS-Plus' programme.

METHODS

A retrospective survey of centralised M. tuberculosis laboratory records of all culture-positive cases over an 8-year period. The drug susceptibility of the isolates was determined using the absolute concentration method. Isolates obtained from patients with a history of previous treatment were further analysed for trends of changes in susceptibility to first- and second-line drugs.

RESULTS

Of 1921 patients with a previous history of treatment and positive cultures, 1425 (74.2%) had isolates susceptible to all four first-line drugs, while 176 (9.2%) were multidrug-resistant (MDR-TB). For the MDR-TB group, 101 (57.4%) isolates were sensitive to all second-line drugs, while 30 (17.0%) were resistant to three or more second-line drugs.

CONCLUSION

In a DOTS-Plus programme environment where there is strict control on use of second-line drugs, the prevalence of MDR-TB is low amongst retreatment cases and the prudent use of second-line drugs in a population with well functioning DOTS-Plus programme does not generate super-resistant strains. In circumstances where most retreatment strains are still susceptible and good laboratory support for detection of MDR cases is available, retreatment using first-line drugs is feasible.

Surveillance of Mycobacterium tuberculosis drug resistance in Hong Kong, 1986-1999, after the implementation of directly observed treatment

OBJECTIVE

To study changing trends in TB epidemiology with emphasis on drug resistance rates in various age groups from 1986-1999.

DESIGN

Laboratory-based data on drug susceptibility testing against streptomycin (SM), isoniazid (NH), rifampicin (RMP) and ethambutol (EMB) had been collected continuously in a centralised TB laboratory in Hong Kong. Epidemiological parameters such as sex, age and drug resistance rates in new and retreatment cases were measured and analysed for longitudinal trends.

RESULTS

Of 48 924 non-duplicate isolates from new TB cases, 7045 (14.4%) were resistant to one or more drugs, 5773 (11.8%) were resistant to SM and/or INH while 881 (1.8%) were multidrug-resistant (MDR-TB). Of 3857 isolates from retreatment patients, 1176 (30.5%) were resistant to one or more drugs, 616 (16.0%) were resistant to SM and/or [NH, and 467 (12.1%) were MDR-TB. For isolates from new cases, significant declines were observed in the resistance rates against any drug, SM alone, INH alone, SM+INH and INH+RMP. For retreatment isolates, significant declines were also observed in resistance to any drug and INH+RMP. In both new and retreatment cases, isolates from patients aged over 65 years showed significantly lower drug resistance (any drug and INH+RMP) compared with other age groups (16-34 years and 35-65 years).

CONCLUSION

With successful implementation of DOTS over a 14-year period, laboratory-based surveillance data showed significant declines in drug resistance, including MDR-TB. This has occurred amidst demographic changes associated with a generally ageing population as well as highly mobile sectors that are in constant exchange with highly endemic areas.

Seventy percent of the Mycobacterium tuberculosis isolates in Hong Kong represent the Beijing genotype

We used spoligotyping to study 500 randomly selected pretreatment Mycobacterium tuberculosis (MTB) strains isolated in Hong Kong during the 2 year period 1998-9. It was found that amongst all MTB strains studied, the 'Beijing' genotype strains were highly prevalent in our geographic area, representing about 70% of the isolates. Unlike previous observations in Vietnam, no significant associations were found either between 'Beijing' genotype strains and all other anti-tuberculosis drug resistance phenotypes, or with particular patients' age groups, except for a weak association with isoniazid susceptibility. Eighteen of these strains exhibited spoligotype patterns that were similar but not identical to the 'Beijing' specific pattern. This is the first geographical area where genetic diversity among 'Beijing' genotype of MTB strains has been observed on this scale.

IS6110 dot blot hybridization for the identification of Mycobacterium tuberculosis complex

To explore a simple, rapid, and inexpensive way to identify Mycobacterium tuberculosis complex culture, dot blot hybridization using IS6110 as the marker was performed against 2788 known clinical isolates of mycobacteria including M. tuberculosis (n = 721), M. kansasii (177), M. marinum (10), M. avium complex (700), M. terrae complex (203), M. fortuitum (476), M. chelonae (439), and other nonpigmented Runyon's Group IV mycobacteria (62). We found that the sensitivity and specificity of the test were 94.3% and 100%, respectively. When this method was evaluated in a laboratory blind study of 1253 initially unknown clinical isolates, its sensitivity and specificity were 91.2% and 100%, respectively. Because this identification test is technically simple, rapid, and can be done in batches, together with its high sensitivity and specificity, it is a cost-effective method for routine identification of M. tuberculosis complex in laboratories of areas with a high incidence of tuberculosis.

Occurrence of genetic segregation in a putative haploid strain of Endomyces fibuliger met by spontaneous sectoring of protoplast fusants

Detailed genetic analysis of Endomyces fibuliger, an amylolytic yeast which is homothallic and exists predominantly in the diploid state, has not been performed. From a naturally occurring strain, E. fibuliger 8014 met, a morphological mutant, 193 met, was obtained by u.v. mutagenesis. To obtain a haploid strain suitable for genetic analysis, an intergeneric hybrid between E. fibuliger 193 met and a strain of a closely related dimorphic heterothallic lipolytic yeast, Yarrowia lipolytica, A his1, was produced by mass mating. The intergeneric hybrid was highly unstable in vegetative culture on yeast extract/phosphate/soluble starch/agar media and produced numerous mitotic sectors. Most of the sectors were mitotically unstable. However, one mitotically stable sector, N14i60 met, was obtained which also differed from the strain 193 as gauged by the appearance of DNA bands on pulsed-field gel electrophoresis. The putative haploid strain, N14i60 met, had six bands whilst the mutant 193 met had seven. Ultra-violet treatment of cells of N14i60 met produced 19 auxotrophic mutants. Protoplast fusion between pairs of different mutants showed complementation and the fusants were unstable mitotically and gave unstable aneuploid and stable haploid sectors of parental and non-parental combinations of markers. It is postulated that complementary diploid fusants, which were obtained by protoplast fusion, produced sectors by mitotic non-disjunction. Such a mechanism provides a means to establish a genetic analysis system for E. fibuliger via the parasexual cycle.

Characterization of Mycobacterium fortuitum isolates from sternotomy wounds by antimicrobial susceptibilities, plasmid profiles, and ribosomal ribonucleic acid gene restriction patterns

An outbreak of sternotomy infections due to Mycobacterium fortuitum in patients who had received cardiovascular surgery occurred in a cardiothoracic hospital in Hong Kong, and 21 such isolates from different patients had antimicrobial susceptibility studies against 14 drugs in vitro. These isolates were also studied for plasmid profiles and ribosomal ribonucleic acid gene restriction patterns. The latter method proved valuable in categorization of these isolates into two groups (comprising of nine and seven isolates, respectively) and five other sporadic strains. When the plasmid profiles and ribotyping are matched against the clinical and epidemiologic data, multisource contamination is suspected to be responsible for the outbreak. The organisms were probably derived from the environment rather than contaminated surgical equipments and materials.