Early-life infections in association with the development of atopic dermatitis in infancy and early childhood: a nationwide nested case-control study.

BACKGROUND: Microbial dysbiosis has been implicated in the development of atopic dermatitis (AD). The risk of development of AD following early-life infections remains unclear. OBJECTIVE: To investigate the impact of early-life infections on AD development. METHODS: This population-based nested case-control study was conducted using the Taiwan's National Health Insurance Research Database. A total of 5454 AD patients and 16 362 control subjects without AD were identified, for the period 1997 to 2013. Demographic characteristics, comorbidities and maternal factors were compared. Adjusted odds ratio (aOR) was calculated to examine the associations between early-life infections and subsequent AD by conditional stepwise logistic regression analysis. RESULTS: Mean age was 2.6 ± 2.9 years in both groups. Overall infections (41.8% vs. 28.9%) before the diagnosis of AD were more common in AD patients than in control subjects (P < 0.001). Infectious diseases [aOR, 1.40; 95% confidence interval (CI), 1.29-1.51], skin infections (aOR, 1.55; 95% CI, 1.40-1.71) and systemic antibiotic exposure (aOR 1.67, 95% CI 1.55-1.79) before AD diagnosis were independently associated with AD development on multivariate analyses. These results were consistent across observation periods (0-1, 1-2 and >2 years after birth) and sensitivity analyses after redefining the index date as 3 or 6 months before the date of AD diagnosis. Other independent risk factors included asthma, allergic rhinitis, intussusception and neonatal hyperbilirubinemia. No association with subsequent AD was found for maternal age at delivery, Caesarean delivery or prenatal antibiotic exposure. CONCLUSION: Infections in early life are associated with AD development in infancy and early childhood.

Influenza vaccine failure in the tropics: a retrospective cohort study of waning effectiveness.

Influenza vaccine effectiveness (VE) wanes over the course of a temperate climate winter season but little data are available from tropical countries with year-round influenza virus activity. In Singapore, a retrospective cohort study of adults vaccinated from 2013 to 2017 was conducted. Influenza vaccine failure was defined as hospital admission with polymerase chain reaction-confirmed influenza infection 2-49 weeks after vaccination. Relative VE was calculated by splitting the follow-up period into 8-week episodes (Lexis expansion) and the odds of influenza infection in the first 8-week period after vaccination (weeks 2-9) compared with subsequent 8-week periods using multivariable logistic regression adjusting for patient factors and influenza virus activity. Records of 19 298 influenza vaccinations were analysed with 617 (3.2%) influenza infections. Relative VE was stable for the first 26 weeks post-vaccination, but then declined for all three influenza types/subtypes to 69% at weeks 42-49 (95% confidence interval (CI) 52-92%, P = 0.011). VE declined fastest in older adults, in individuals with chronic pulmonary disease and in those who had been previously vaccinated within the last 2 years. Vaccine failure was significantly associated with a change in recommended vaccine strains between vaccination and observation period (adjusted odds ratio 1.26, 95% CI 1.06-1.50, P = 0.010).

Persistence of meticillin-resistant Staphylococcus aureus carriage in re-admitted patients.

A retrospective cohort study was conducted to investigate the duration and risk factors for persistence of meticillin-resistant Staphylococcus aureus (MRSA) colonization among known carriers who were re-admitted to hospital. MRSA carriage persisted in a high proportion of known carriers up to two years after their last date of discharge, and re-admission screening should be performed for at least this duration. A targeted screening approach should focus on older patients with a history of long inpatient stays, who are at higher risk of persistent carriage. Timely discharge planning is important in reducing the risk of persistent MRSA colonization among known carriers.

Contacts of healthcare workers, patients and visitors in general wards in Singapore.

To characterize contacts in general wards, a prospective survey of healthcare workers (HCWs), patients and visitors was conducted using self-reported diary, direct observation and telephone interviews. Nurses, doctors and assorted HCWs reported a median of 14, 18 and 15 contact persons over one work shift, respectively. Within 1 h, we observed 3·5 episodes with 25·6 min of cumulative contact time for nurses, 2·9 episodes and 22·1 min for doctors and 5·0 episodes with 44·3 min for assorted-HCWs. In interactions with patients, nurses had multiple brief episodes of contact; doctors had fewer episodes and less cumulative contact time; assorted-HCWs had fewer contact episodes of longer durations (than for nurses and doctors). Assortative mixing occurred amongst HCWs: those of the same HCW type were the next most frequent class of contact after patients. Over 24-h, patients contacted 14 persons with 23 episodes and 314·5 min of contact time. Patient-to-patient contact episodes were rare, but a maximum of five were documented from one patient participant. 22·9% of visitors reported contact with patients other than the one they visited. Our study revealed differences in the characteristics of contacts among different HCW types and potential transmission routes from patients to others within the ward environment.

Risk assessment and laboratory investigation of respiratory illness in travellers returning to Singapore 2012-2015: experience from the MERS-CoV Surveillance Programme.

Since the emergence of Middle East respiratory syndrome coronavirus (MERS-CoV), Singapore has enhanced its national surveillance system to detect the potential importation of this novel pathogen. Using the guidelines from the Singapore Ministry of Health, a suspect case was defined as a person with clinical signs and symptoms suggestive of pneumonia or severe respiratory infection with breathlessness, and with an epidemiological link to countries where MERS-CoV cases had been reported within the preceding 14 days. This report describes a retrospective review of 851 suspected MERS-CoV cases assessed at the adult tertiary-care hospital in Singapore between September 2012 and December 2015. In total, 262 patients (31%) were hospitalized. All had MERS-CoV infection ruled out by RT-PCR or clinical assessment. Two hundred and thirty (88%) of the hospitalized patients were also investigated for influenza virus by RT-PCR. Of these, 62 (27%) tested positive for seasonal influenza. None of the patients with positive influenza results had been vaccinated in the year prior to hospital admission. Ninety-three (36%) out of the 262 hospitalized patients had clinical and/or radiological evidence of pneumonia. This study demonstrates the potential benefits of pre-travel vaccination against influenza and pneumococcal disease.

Tyrosine phosphorylation of cofilin at Y68 by v-Src leads to its degradation through ubiquitin-proteasome pathway.

Cofilin is a major regulator of actin dynamics involved in the regulation of cell spreading and migration through its actin depolymerizing and severing activities. v-Src is an activated Src tyrosine kinase and a potent oncogene known to phosphorylate a variety of cellular proteins in cell transformation process including altered cell adhesion, spreading and migration. Recently, it has been suggested that cofilin is a potential substrate of v-Src (Rush et al., 2005). Here, we show direct tyrosine phosphorylation of cofilin by v-Src and identify Y68 as the major phosphorylation site. Cofilin phosphorylation at Y68 did not change its activity per se, but induced increased ubiquitination of cofilin and its degradation through the proteosome pathway. Furthermore, the negative effect of cofilin on cellular F-actin contents was inhibited by coexpression of v-Src, whereas that of cofilin mutant Y68F (Y68 mutated to F) was not affected, suggesting that v-Src-mediated cofilin phosphorylation at Y68 is required for the degradation of cofilin in vivo. Lastly, inhibition of cell spreading by v-Src was rescued partially by coexpression of cofilin, and to a greater extent by the Y68F mutant, which is not subjected to v-Src-induced degradation through phosphorylation, suggesting that v-Src-mediated changes in cell spreading is, at least in part, through inhibiting the function of cofilin through phosphorylating it at Y68. Together, these results suggest a novel mechanism by which cofilin is regulated by v-Src through tyrosine phosphorylation at Y68 that triggers the degradation of cofilin through ubiquitination-proteosome pathway and consequently inhibits cofilin activity in reducing cellular F-actin contents and cell spreading.

Development and preliminary validation of a systemic lupus erythematosus-specific quality-of-life instrument (SLEQOL).

OBJECTIVES: Systemic lupus erythematosus (SLE), a chronic illness with an unpredictable and variable course, profoundly affects the quality of life (QOL). General health questionnaires are used to assess QOL in SLE, but a disease-specific instrument could offer enhanced responsiveness and content validity. We detail the steps we took to develop and validate a new SLE-specific QOL instrument, SLEQOL. METHODS: Rheumatology professionals nominated items that they felt were important determinants of QOL of SLE patients. One hundred SLE patients were asked to assess the importance and frequency of occurrence of these items and to suggest those that had not been listed. Item reduction was performed using Rasch model and factor analyses to create a new questionnaire in English. This final questionnaire was administered to a cohort of 275 patients to study its psychometric properties. RESULTS: Fifty-one items covering a wide range of QOL concerns were identified. The patients' responses led to the elimination of 11. The new questionnaire of 40 items was found to have Cronbach's alpha of 0.95 and to consist of eight domains covering physical, mental and social QOL issues. It has good test-retest reliability, poor to fair cross-sectional correlation with the SF-36, with poor correlation with lupus activity or damage indices. The SLEQOL was more responsive to change than the SF-36. CONCLUSIONS: We have developed a new 40-item SLEQOL in English and showed that it is valid for use in SLE patients in Singapore. It offers better content validity and responsiveness to change than the SF-36.

Profound difference in pharmacokinetics between morin and its isomer quercetin in rats.

Morin and quercetin are isomeric antioxidant flavonols widely distributed in plant foods and herbs. The pharmacokinetics of both flavonols at two doses were investigated and compared in rats. Parent forms and their glucuronides and sulfates in serum were determined by HPLC before and after enzymatic hydrolysis, respectively. After oral dosing of morin, both the parent form, morin, and its glucuronides and sulfates were present in the bloodstream. The conjugated metabolites predominated at the dose of 25 mg kg(-1), whereas the parent form was predominant at the dose of 50 mg kg(-1). Moreover, the AUC of morin parent form increased by a factor of 37 when the dose doubled, indicating that morin showed nonlinear pharmacokinetics. On the other hand, quercetin presented only as glucuronides and sulfates in the blood, indicating negligible bioavailability of quercetin, and the metabolites showed linear pharmacokinetics at the two doses studied. When considering the total AUC of parent form with conjugated metabolites, the extent of absorption of morin was 3 fold that of quercetin at the dose of 50 mg kg(-1). The results indicated that the difference in hydroxylation pattern on B-ring of flavonol markedly affected their fates in rats.

Quercetin glucuronides inhibited 2-aminofluorene acetylation in human acute myeloid HL-60 leukemia cells.

Our earlier study has demonstrated that following the exposure of rat to the arylamine carcinogen 2-aminofluorene, DNA-2-aminofluorene adducts were found in the target tissues liver, bladder, colon, lung and also in circulating leukocytes (lymphocytes and monocytes). The result also demonstrated that orally treated antioxidants decreased N-acetylation of 2-aminofluorene in target tissues and leukocytes. Therefore, this study investigated whether quercetin glucuronides could affect N-acetylation of 2-aminofluorene in human acute myeloid leukemia HL-60 cells. Evidence is presented here that human leukemia cells are capable of acetylating 2-aminofluorene. Quercetin glucuronides did inhibit 2-aminofluorene acetylation in intact cells. The results also indicated that quercetin glucuronides induced cytotoxicity in dose-dependent manner in the examined human acute myeloid leukemia HL-60 cells.

Determinations of morin, quercetin and their conjugate metabolites in serum.

Morin and quercetin are isomeric antioxidant flavonols. High-performance liquid chromatographic methods were developed for the quantitation of morin and quercetin in serum. The method employed a Cosmosil RP-18 column, using acetonitrile/0.2% o-phosphoric acid 28/72 and 27/73 (v/v) as mobile phases, with ethyl paraben and 6,7-dimethoxycoumarin used as internal standards for morin and quercetin, respectively. Moreover, a strategy to stabilize morin/quercetin released from their glucuronides/sulfates in serum during hydrolysis was established. The present methods are applicable for determining morin, quercetin, and their glucuronides/sulfates in serum.

Rapid prenatal diagnosis of Hb Bart's hydrops fetalis in southeast Asia area by polymerase chain reaction.

We used the polymerase chain reaction (PCR) to amplify the breakpoint area of alpha-thalassemia-1 of Southeast Asia type and several parts of the alpha-globin gene cluster to make a differential diagnosis between alpha-thalassemia-1 and Hb Bart's hydrops fetalis. The procedure involved three primers to detect the homozygote of alpha-thalassemia-1, then amplifies the other alpha-globin gene cluster with three other pairs of primers to double check the results. The PCR products were checked again by allele specific probes. Twenty-two cases were diagnosed prenatally, two were normal, 17 were alpha-thalassemia-1, and three Hb Bart's hydrops fetalis. All cases were confirmed either by Southern blot hybridization or follow-up by sonography or after delivery. No false positive or false negative results were obtained by our strigent procedure. We conclude it to be a rapid, accurate and economic method.

Inhibition of methylation of DNA and tRNA by adenosine in an adenosine-sensitive mutant of the baby hamster kidney cell line.

An adenosine-sensitive (Ados) mutant of baby hamster kidney (BHK) cells, ara-S10d, when treated with a toxic concentration of adenosine (Ado), displayed a substantial elevation of S-adenosylhomocysteine (SAH), S-adenosylmethionine (SAM), and methylthioadenosine (MTA). Wild-type BHK cells treated with the same concentration of Ado (not toxic to these parental cells) produced an elevation of SAH 1.5 times higher than that of ara-S10d cells without a concurrent elevation of SAM or MTA. Inhibition of methylation of DNA and tRNA is greater in ara-S10d cells treated with Ado than that of similarly treated wild-type cells. This inhibition was correlated with the enhanced Ado toxicity, suggesting inhibition of methylation as a possible causal factor for the great increase in Ado sensitivity. Inhibition of methylation may be due to the elevated level of MTA and not solely to the elevation of SAH, a well-known potent inhibitor of numerous methyltransferases.

Multiple mechanisms of adenosine toxicity in an adenosine sensitive mutant of baby hamster kidney (BHK) cells.

A class of arabinosyladenine-resistant baby hamster kidney (BHK) cell mutants, isolated in our laboratory, shows cross-resistance to deoxyadenosine, alteration of adenosine kinase, elevation of spontaneous mutation rate, and extreme sensitivity to adenosine. One of these adenosine sensitive mutants, ara-s10d, was isolated spontaneously and studies with Ador revertants suggest the involvement of a single pleiotropic mutation. The enhanced adenosine toxicity in ara-s10d cells can be attributed to pyrimidine nucleotide starvation and to at least one other mechanism, which is associated with a 200-fold elevation of IMP, 3-5 fold elevation of ATP, GTP, S-adenosylmethionine (AdoMet) and methylthioadenosine (MeSAdo).