Accelerating TB diagnosis during the COVID-19 pandemic.

SETTING: The COVID-19 pandemic has caused significant disruption worldwide to economies and healthcare systems, even those with well-developed infrastructure.OBJECTIVE: To examine the effects of COVID-19 on TB diagnosis in Singapore, and to identify any factors that could facilitate early detection of TB among persons screened.DESIGN: To assess the impact of testing and diagnosis of the pandemic on TB, the number of TB-related tests from January 2018 to December 2020 were collected. We also conducted a retrospective case-control study of all adult patients admitted for COVID-19, TB or coinfection from 23 January to 31 May 2020.RESULTS: Nationwide testing for TB from 2018 to 2020 increased by 24.2%. We analysed 253 adult inpatients, of whom 107 (42.3%) were diagnosed with COVID-19, 134 (53.0%) had TB, while 12 (4.7%) had co-infection. Patients with TB were more likely to have chest X-ray abnormalities than those with COVID-19 (89.9% vs. 76.0%; P < 0.01). Patients with TB were more likely to have prolonged cough vs. those with COVID-19 infection (28 vs. 5 days; P < 0.01).CONCLUSION: Early screening for TB, even among patients with COVID-19, could lead to earlier diagnosis and treatment, thereby breaking the chain of transmission.

Dose-Response Relationship Between Diltiazem and Tacrolimus and Its Safety in Renal Transplant Recipients.

BACKGROUND: Inhibition of calcineurin inhibitor (CNI) metabolism with diltiazem reduces the dose of tacrolimus required to achieve its therapeutic blood concentration in kidney transplant recipients (KTRs). This cost-savings maneuver is practiced in several countries, including Malaysia, but the actual impacts of diltiazem on tacrolimus blood concentration, dose-response relationship, cost-savings, and safety aspects are unknown. METHODS: This retrospective study was performed on all KTRs ≥18 years of age at our center from January 1, 2006 to December 31, 2015, who were prescribed diltiazem as tacrolimus-sparing agent. Blood tacrolimus trough level (TacC0) and other relevant clinical data for 70 eligible KTRs were reviewed. RESULTS: The dose of 1 mg tacrolimus resulted in a median TacC0 of 0.83 ± 0.52 ng/mL. With the introduction of a 90-mg/d dose diltiazem, there was a significant TacC0 increase to 1.39 ± 1.31 ng/mL/mg tacrolimus (P < .01). A further 90-mg increase in diltiazem to 180 mg/d resulted in a further increase of TacC0 to 1.66 ± 2.58 ng/mL/mg tacrolimus (P = .01). After this, despite a progressive increment of every 90-mg/d dose diltiazem to 270 mg/d and 360 mg/d, there was no further increment in TacC0 (1.44 ± 1.15 ng/mL/mg tacrolimus and 1.24 ± 0.94 ng/mL/mg tacrolimus, respectively [P < .01]). Addition of 180 mg/d diltiazem reduced the required tacrolimus dose to 4 mg/d, resulting in a cost-savings of USD 2045.92 per year (per patient) at our center. Adverse effects reported within 3 months of diltiazem introduction were bradycardia (1.4%) and postural hypotension (1.4%), which resolved after diltiazem dose reduction. CONCLUSION: Coadministration of tacrolimus and diltiazem in KTRs appeared to be safe and resulted in a TacC0 increment until reaching a 180-mg/d total diltiazem dose, at which point it began to decrease. This approach will result in a marked savings in immunosuppression costs among KTRs in Malaysia.

Recellularization of decellularized adipose tissue-derived stem cells: role of the cell-secreted extracellular matrix in cellular differentiation.

Adipose-derived stem cells (ASCs) are found in a location within the adipose tissue known as the stem cell niche. The ASCs in the niche are maintained in the quiescent state, and upon exposure to various microenvironmental triggers are prompted to undergo proliferation or differentiation. These microenvironmental triggers also modulate the extracellular matrix (ECM), which interacts with the cells through the cytoskeleton and induces downstream events inside the cells that bring about a change in cell behaviour. In response to these changes, the cells remodel the ECM, which will differ according to the type of tissue being formed by the cells. As the ECM itself plays an important role in the regulation of cellular differentiation, this study aims to explore the role of the cell-secreted ECM at various stages of differentiation of stem cells in triggering the differentiation of ASCs. To this end, the ASCs cultured in proliferation, osteogenic and adipogenic media were decellularized and the secreted ECM was characterized. Overall, it was found that osteo-differentiated ASCs produced higher amounts of collagen and glycosaminoglycans (GAG) compared to the undifferentiated and adipo-differentiated ASCs. The two types of differentiated ECMs were subsequently shown to trigger initial but not terminal differentiation of ASCs into osteo- and adipo-lineages respectively, as indicated by the upregulation of lineage specific markers. In addition, integrin subunits alpha (α) 6 and integrin beta (ß) 1 were found to be produced by ASCs cultured on cell-secreted ECM-coated substrates, suggesting that the integrins α6 and ß1 play an instrumental role in cell-ECM interactions. Taken together, this study demonstrates the importance of the ECM in cellular fate decisions and how ECM-coated substrates can potentially be used for various tissue engineering applications.

Parental pre-pregnancy BMI is a dominant early-life risk factor influencing BMI of offspring in adulthood.

OBJECTIVE: We examined parental and early-life variables in order to identify risk factors for adulthood overweight and obesity in offspring. We report here on the longitudinal prevalence of overweight and obesity in Australian children born between 1989 and 1991 and followed from birth to age 22. METHODS: Data were analysed on 1355 participants from the Western Australian Pregnancy Cohort (Raine) Study, with anthropometry collected during pregnancy, at birth, one year and at three yearly intervals thereafter. Multivariate analyses and cross-sectional logistic regression quantified the timing and contribution of early-life risk factors for overweight and obesity in young-adulthood. RESULTS: At five years of age 12.6% of children were overweight and 5.2% were obese. By early adulthood, the prevalence of obesity had increased to 12.8%, whilst overweight remained relatively stable at 14.2% (range from early childhood to adulthood 11-16%). Parental pre-pregnancy body mass index (BMI) was the strongest determinant of adult offspring BMI. Although rapid first year weight gain was associated with increased offspring BMI, the impact of first year weight-gain diminished over childhood, whilst the impact of parental BMI increased over time. CONCLUSIONS: Parental pre-pregnancy BMI and rapid early-life weight gain predispose offspring to obesity in adulthood.

Fingerprint verification prediction model in hand dermatitis.

BACKGROUND: Hand dermatitis associated fingerprint changes is a significant problem and affects fingerprint verification processes. This study was done to develop a clinically useful prediction model for fingerprint verification in patients with hand dermatitis. METHODS: A case-control study involving 100 patients with hand dermatitis. All patients verified their thumbprints against their identity card. Registered fingerprints were randomized into a model derivation and model validation group. Predictive model was derived using multiple logistic regression. Validation was done using the goodness-of-fit test. RESULTS: The fingerprint verification prediction model consists of a major criterion (fingerprint dystrophy area of ≥ 25%) and two minor criteria (long horizontal lines and long vertical lines). The presence of the major criterion predicts it will almost always fail verification, while presence of both minor criteria and presence of one minor criterion predict high and low risk of fingerprint verification failure, respectively. When none of the criteria are met, the fingerprint almost always passes the verification. The area under the receiver operating characteristic curve was 0.937, and the goodness-of-fit test showed agreement between the observed and expected number (P = 0.26). CONCLUSIONS: The derived fingerprint verification failure prediction model is validated and highly discriminatory in predicting risk of fingerprint verification in patients with hand dermatitis.

Isolation and characterization of CCoAOMT in interspecific hybrid of Acacia auriculiformis x Acacia mangium--a key gene in lignin biosynthesis.

This study was directed at the understanding of the function of CCoAOMT isolated from Acacia auriculiformis x Acacia mangium. Full length cDNA of the Acacia hybrid CCoAOMT (AhCCoAOMT) was 1024-bp long, containing 750-bp coding regions, with one major open reading frame of 249 amino acids. On the other hand, full length genomic sequence of the CCoAOMT (AhgflCCoAOMT) was 2548 bp long, containing three introns and four exons with a 5' untranslated region (5'UTR) of 391 bp in length. The 5'UTR of the characterized CCoAOMT gene contains various regulatory elements. Southern analysis revealed that the Acacia hybrid has more than three copies of the CCoAOMT gene. Real-time PCR showed that this gene was expressed in root, inner bark, leaf, flower and seed pod of the Acacia hybrid. Downregulation of the homologous CCoAOMT gene in tobacco by antisense (AS) and intron-containing hairpin (IHP) constructs containing partial AhCCoAOMT led to reduction in lignin content. Expression of the CCoAOMT in AS line (pART-HAS78-03) and IHP line (pART-HIHP78-06) was reduced respectively by 37 and 75% compared to the control, resulting in a decrease in the estimated lignin content by 24 and 56%, respectively. AhCCoAOMT was found to have altered not only S and G units but also total lignin content, which is of economic value to the pulp industry. Subsequent polymorphism analysis of this gene across eight different genetic backgrounds each of A. mangium and A. auriculiformis revealed 47 single nucleotide polymorphisms (SNPs) in A. auriculiformis CCoAOMT and 30 SNPs in A. mangium CCoAOMT.

Proposed mechanism of antibacterial action of chemically modified apatite for reduced bone infection.

Surface-bound silver ions were demonstrated to be responsible for the antibacterial action of silver, silicon-containing hydroxyapatite (Ag,Si-HA). X-ray photoelectron spectroscopy, transmission electron microscopy, and induced coupled plasma spectroscopy results suggested that silver ions in the crystal structure diffused toward the crystal surface of Ag,Si-HA, and interacted with adherent Staphylococcus aureus bacteria, thus damaging the cell wall and inducing leakage of potassium ions. All these steps constitute the mechanism of antibacterial action for Ag,Si-HA. Consequently, Ag,Si-HA gave rise to a 7-log reduction of the adherent bacteria as compared to HA and Si-HA at 168 h. Silicon in Ag,Si-HA helped to mitigate the reduced effect of bone differentiation in Ag-HA as shown in the alkaline phosphatase, type I collagen and osteocalcin results, promoting enhanced biological response, without compromising the antibacterial property. On the whole, Ag,Si-HA containing an optimized content of 0.5 wt % silver and 0.7 wt % silicon provides antibacterial properties and enhanced biological response.

Identification of floral genes for sex determination in Calamus palustris Griff. by using suppression subtractive hybridization.

Calamus palustris Griff. is an economically important dioecious rattan species in Southeast Asia. However, dioecy and onset of flowering at 3-4 years old render uncertainties in desired female:male seedling ratios to establish a productive seed orchard for this rattan species. We constructed a subtractive library for male floral tissue to understand the genetic mechanism for gender determination in C. palustris. The subtractive library produced 1536 clones with 1419 clones of high quality. Reverse Northern screening showed 313 clones with differential expression, and sequence analyses clustered them into 205 unigenes, including 32 contigs and 173 singletons. The subtractive library was further validated with reverse transcription-quantitative polymerase chain reaction analysis. Homology identification classified the unigenes into 12 putative functional proteins with 83% unigenes showing significant match to proteins in databases. Functional annotations of these unigenes revealed genes involved in male flower development, including MADS-box genes, pollen-related genes, phytohormones for flower development, and male flower organ development. Our results showed that the male floral genes may play a vital role in sex determination in C. palustris. The identified genes can be exploited to understand the molecular basis of sex determination in C. palustris.

Bioassay and biochemical studies of the status of pirimiphos-methyl and cypermethrin resistance in Aedes (Stegomyia) aegypti and Aedes (Stegomyia) albopictus (Diptera: Culicidae) in Singapore.

Aedes (Stegomyia) aegypti (Linnaeus) and Ae. (Stegomyia) albopictus (Skuse) were sampled from five regions of Singapore (Central, North East, North West, South East and South West) and tested with diagnostic concentrations of the technical grade insecticides, pirimiphos-methyl and cypermethrin. Biochemical assays were performed on the same populations of Ae. aegypti and Ae. albopictus to determine activities of detoxifying enzymes, including non-specific esterase (EST), monooxygenase (MFO) and acetylcholinesterase (AChE). The diagnostic test showed that all Ae. aegypti populations were susceptible to pirimiphos-methyl (mortality = 99 to 100%), but resistant to cypermethrin (mortality = 11 to 76%). Resistance to pirimiphos-methyl was observed in all Ae. albopictus populations (mortality = 49 to 74%) while cypermethrin resistance was detected in most Ae. albopictus populations (mortality = 40 to 75%), except those from Central (mortality = 86%) and South East (mortality = 94%) showing incipient resistance. The biochemical assays showed that there was significant enhancement (P < 0.001) of MFO activity in pyrethroid-resistant Ae. albopictus populations and most Ae. aegypti populations. The biochemical assay results suggested that AChE could play a role in pirimiphos-methyl resistance of Ae. albopictus in South West, South East and North East regions. The small but significant increase in EST activities in Ae. aegypti from all regions suggest that it may play a role in the observed cypermethrin resistance.

Bioassay and biochemical studies of the status of pirimiphos-methyl and cypermethrin resistance in Aedes (Stegomyia) aegypti and Aedes (Stegomyia) albopictus (Diptera: Culicidae) in Singapore Singapore 138667

Aedes (Stegomyia) aegypti (Linnaeus) and Ae. (Stegomyia) albopictus (Skuse) were sampled from five regions of Singapore (Central, North East, North West, South East and South West) and tested with diagnostic concentrations of the technical grade insecticides, pirimiphos-methyl and cypermethrin. Biochemical assays were performed on the same populations of Ae. aegypti and Ae. albopictus to determine activities of detoxifying enzymes, including non-specific esterase (EST), monooxygenase (MFO) and acetylcholinesterase (AChE). The diagnostic test showed that all Ae. aegypti populations were susceptible to pirimiphos-methyl (mortality = 99 to 100%), but resistant to cypermethrin (mortality = 11 to 76%). Resistance to pirimiphos-methyl was observed in all Ae. albopictus populations (mortality = 49 to 74%) while cypermethrin resistance was detected in most Ae. albopictus populations (mortality = 40 to 75%), except those from Central (mortality = 86%) and South East (mortality = 94%) showing incipient resistance. The biochemical assays showed that there was significant enhancement (P < 0.001) of MFO activity in pyrethroid-resistant Ae. albopictus populations and most Ae. aegypti populations. The biochemical assay results suggested that AChE could play a role in pirimiphos-methyl resistance of Ae. albopictus in South West, South East and North East regions. The small but significant increase in EST activities in Ae. aegypti from all regions suggest that it may play a role in the observed cypermethrin resistance.

DICER1 hotspot mutations in non-epithelial gonadal tumours.

BACKGROUND: Non-epithelial gonadal tumours largely comprise sex cord-stromal tumours (SCSTs) and germ cell tumours (GCTs). Specific somatic mutations in DICER1, a microRNA maturation pathway gene, have been identified in these tumours. We conducted a study that aimed to confirm, refine and extend the previous observations. METHODS: We used Sanger sequencing to sequence the RNase IIIa and IIIb domains of DICER1 in 154 gonadal tumours from 135 females and 19 males, as well as 43 extra-gonadal GCTs from 26 females and 17 males. RESULTS: We identified heterozygous non-synonymous mutations in the RNase IIIb domain of DICER1 in 14/197 non-epithelial tumours (7.1%). Mutations were found in 9/28 SCSTs (32%), 5/118 gonadal GCTs (4.2%), 0/43 extra-gonadal GCTs and 0/8 miscellaneous tumours. The 14 mutations affected only five residues: E1705, D1709, E1788, D1810 and E1813. In all five patients where matched and constitutional DNA was available, the mutations were only somatic. There were no mutations found in the RNase IIIa domain. CONCLUSION: More than half (8/15) of Sertoli-Leydig cell tumours (SLCTs) harbour DICER1 mutations in the RNase IIIb domain, while mutations are rarely found in GCTs. Genetic alterations in SLCTs may aid in classification and provide new approaches to therapy.

Biallelic DICER1 mutations occur in Wilms tumours.

DICER1 is an endoribonuclease central to the generation of microRNAs (miRNAs) and short interfering RNAs (siRNAs). Germline mutations in DICER1 have been associated with a pleiotropic tumour predisposition syndrome and Wilms tumour (WT) is a rare manifestation of this syndrome. Three WTs, each in a child with a deleterious germline DICER1 mutation, were screened for somatic DICER1 mutations and were found to bear specific mutations in either the RNase IIIa (n = 1) or the RNase IIIb domain (n = 2). In the two latter cases, we demonstrate that the germline and somatic DICER1 mutations were in trans, suggesting that the two-hit hypothesis of tumour formation applies for these examples of WT. Among 191 apparently sporadic WTs, we identified five different missense or deletion somatic DICER1 mutations (2.6%) in four individual WTs; one tumour had two very likely deleterious somatic mutations in trans in the RNase IIIb domain (c.5438A>G and c.5452G>A). In vitro studies of two somatic single-base substitutions (c.5429A>G and c.5438A>G) demonstrated exon 25 skipping from the transcript, a phenomenon not previously reported in DICER1. Further we show that DICER1 transcripts lacking exon 25 can be translated in vitro. This study has demonstrated that a subset of WTs exhibits two 'hits' in DICER1, suggesting that these mutations could be key events in the pathogenesis of these tumours.

Zinc-substituted hydroxyapatite: a biomaterial with enhanced bioactivity and antibacterial properties.

Hydroxyapatite (HA) is a synthetic biomaterial and has been found to promote new bone formation when implanted in a bone defect site. However, its use is often limited due to its slow osteointegration rate and low antibacterial activity, particularly where HA has to be used for long term biomedical applications. This work will describe the synthesis and detailed characterization of zinc-substituted HA (ZnHA) as an alternative biomaterial to HA. ZnHA containing 1.6 wt% Zn was synthesized via a co-precipitation reaction between calcium hydroxide, orthophosphoric acid and zinc nitrate hexahydrate. Single-phase ZnHA particles with a rod-like morphology measuring ~50 nm in length and ~15 nm in width, were obtained and characterized using transmission electron microscopy and X-ray diffraction. The substitution of Zn into HA resulted in a decrease in both the a- and c-axes of the unit cell parameters, thereby causing the HA crystal structure to alter. In vitro cell culture work showed that ZnHA possessed enhanced bioactivity since an increase in the growth of human adipose-derived mesenchymal stem cells along with the bone cell differentiation markers, were observed. In addition, antibacterial work demonstrated that ZnHA exhibited antimicrobial capability since there was a significant decrease in the number of viable Staphylococcus aureus bacteria after in contact with ZnHA.

The impact of off-pump coronary artery bypass surgery on postoperative renal function.

OBJECTIVES: A number of risk factors have been recognised for postoperative renal dysfunction following on-pump coronary artery bypass surgery (CABG). There are, however, few studies that have evaluated the potential reno-protective effects of off-pump CABG in the presence of other confounding risk factors. The aim of this study was to determine if off-pump CABG reduces the risk of renal injury. METHODS: Serum creatinine values (preoperatively and day 1, 2 and 4 postoperatively) and other clinical data were prospectively collected on 1580 consecutive patients who underwent first-time CABG from 2002 to 2005. Creatinine clearance was calculated using the Cockcroft and Gault equation. The effect of on-pump vs. off-pump CABG on renal function was analysed, adjusting for age, gender, diabetes mellitus, left ventricular (LV) function and preoperative creatinine clearance, using multiple regression analysis. RESULTS: One thousand one hundred and forty-five (73%) patients underwent on-pump CABG and 435 (27%) underwent off-pump CABG. The two groups were similar with respect to age, gender and diabetes. Two hundred and seventy-four (17%) patients were females and 274 (17%) patients had diabetes. Multivariate analysis demonstrated significantly lower creatinine clearance postoperatively in patients with diabetes (P<0.001) and advanced age (P<0.001). The on-pump group had significantly lower postoperative creatinine clearance in comparison to the off-pump group (P= 0.01). The effect remained consistent after adjusting for potential risk factors (age, diabetes, gender, LV function and preoperative creatinine clearance) in the multivariate analysis. CONCLUSION: Off-pump surgery is associated with a reduction in postoperative renal injury.

Internet-addicted kids and South Korean government efforts: boot-camp case.

Computer overuse has been a serious problem for the past several years. One aspect of the information age has been the novel concerns deriving from advanced IT technology--which include Internet addiction, gambling, and so on. These Internet-based problems have emerged in many countries, including South Korea. In an effort to solve this problem, the South Korean government has created a variety of programs designed to cure teenagers' Internet addictions, most notably the Jump Up Internet Rescue School, a camp designed to cure Internet-addicted or online game-addicted children. In this study, we review this boot-camp program and present a brief review of the literature concerning Internet addiction and habit theory. Additionally, we provide some useful implications for the Korean government and other countries, practitioners, and researchers. It is also anticipated that the findings from this study will provide us with a better understanding of how case-study-based research into Internet addiction curative programs can be regarded as a burgeoning field of Internet-related research.

The utility of transoesophageal echocardiography to determine management in suspected embolic stroke.

BACKGROUND: Assessment for source of stroke is a common indication for transoesophageal echocardiography (TOE). Although an abnormality is frequently found, it remains uncertain how frequently the findings alter patient management. Also, the role of transthoracic echocardiography (TTE) prior to or instead of TOE is not well defined. We sought to determine the use of TTE prior to TOE, the outcome of the TOE and its impact on management. METHODS: We retrospectively reviewed the records and echocardiography results of 100 consecutive patients who underwent TOE for any reason at a tertiary hospital. In 35 subjects (35%), the indication was evaluation for source of stroke. Among these, we determined clinical risk factors for stroke, if a TTE was performed prior to their TOE, the results of the TOE and its effect on management. RESULTS: The mean age of the stroke patients was 64.6 years (17-90) and 49% were women. Eighty per cent had at least one risk factor for stroke and 17% had atrial fibrillation. A TTE, performed in 40% prior to the TOE, found an abnormality in 14% (2/14). The TOE showed an abnormality in 71% of patients; 54% had aortic atheroma; 17% PFO; 14% spontaneous echo contrast; 6% left atrial appendage thrombus, 3% left ventricular thrombus and 3% vegetation. In only one patient (3%) the management was altered based on the abnormal TOE findings. CONCLUSION: An abnormality on TOE, although common (71%) and more sensitive than TTE, altered management in only 3% of subjects referred for stroke assessment. Its role requires further consideration.