Sex-related differences in dispensation of rheumatic medications in older patients with inflammatory arthritis: A population-based study

OBJECTIVE

The aim of our study was to compare dispensation of rheumatic medications between older male and female patients with early rheumatoid arthritis (RA) and psoriatic arthritis (PsA).

METHODS

This retrospective cohort study was performed using health administrative data from Ontario, Canada (years 2010 - 2017) on incident patients with RA and PsA, who were 66 years or older at the time of diagnosis. Yearly dispensation of rheumatic drugs was compared between older male and female patients for three years after diagnosis using multivariable regression models, after adjusting for confounders. The groups of drugs included in the analysis were DMARDs classified as conventional DMARDs (csDMARDs) and advanced therapy (biologic DMARDs (bDMARDs) and targeted synthetic DMARDs (tsDMARDs)), NSAIDs, opioids and oral corticosteroids. Results were reported as Odds Ratios with 95% Confidence Intervals (CI).

RESULTS

We analyzed 13,613 patients (64% females) with RA and 1,116 patients (57% females) with PsA. Female RA patients were more likely to receive opioids (OR [95% CI] 1.39 [1.22-1.58] to 1.51 [1.32-1.72]) and NSAIDs (OR [95% CI] 1.14 (1.04-1.25) to 1.16 [1.04-1.30]). Dispensation of DMARDs showed no sex-difference in either group. Subgroup analyses showed more intense use of advanced therapy in the RA cohort and of csDMARDs in the PsA cohort when patient and physician sex was concordant.

CONCLUSION

This study did not identify any sex difference in use of DMARDs among older RA and PsA patients. Reasons for the higher use of opioids and NSAIDs among female RA patients warrants further research.

Virtual Care and Emergency Department Use During the COVID-19 Pandemic Among Patients of Family Physicians in Ontario, Canada

Importance

The COVID-19 pandemic has played a role in increased use of virtual care in primary care. However, few studies have examined the association between virtual primary care visits and other health care use.

Objective

To evaluate the association between the percentage of virtual visits in primary care and the rate of emergency department (ED) visits.

Design, Setting, and Participants

This cross-sectional study used routinely collected administrative data and was conducted in Ontario, Canada. The sample comprised family physicians with at least 1 primary care visit claim between February 1 and October 31, 2021, and permanent Ontario residents who were alive as of March 31, 2021. All residents were assigned to physicians according to enrollment and billing data.

Exposure

Family physicians' virtual visit rate was the exposure. Physicians were stratified by the percentage of total visits that they delivered virtually (via telephone or video) during the study period (0% [100% in person], >0%-20%, >20%-40%, >40%-60%, >60%-80%, >80% to <100%, or 100%).

Main Outcomes and Measures

Population-level ED visit rate was calculated for each stratum of virtual care use. Multivariable regression models were used to understand the relative rate of patient ED use after adjusting for rurality of practice, patient characteristics, and 2019 ED visit rates.

Results

Data were analyzed for a total of 13 820 family physicians (7114 males [51.5%]; mean [SD] age, 50 [13.1] years) with 12 951 063 patients (6 714 150 females [51.8%]; mean [SD] age, 42.6 [22.9] years) who were attached to these physicians. Most physicians provided between 40% and 80% of care virtually. A higher percentage of the physicians who provided more than 80% of care virtually were 65 years or older, female individuals, and practiced in big cities. Patient comorbidity and morbidity were similar across strata of virtual care use. The mean (SD) number of ED visits was highest among patients whose physicians provided only in-person care (470.3 [1918.8] per 1000 patients) and was lowest among patients of physicians who provided more than 80% to less than 100% of care virtually (242.0 [800.3] per 1000 patients). After adjustment for patient characteristics, patients of physicians with more than 20% of visits delivered virtually had lower rates of ED visits compared with patients of physicians who provided more than 0% to 20% of care virtually (eg, >80% to <100% vs >0%-20% virtual visits in big cities: relative rate, 0.77%; 95% CI, 0.74%-0.81%). This pattern was unchanged across all rurality of practice strata and after adjustment for 2019 ED visit rates. In urban areas, there was a gradient whereby patients of physicians providing the highest level of virtual care had the lowest ED visit rates.

Conclusions and Relevance

Findings of this study show that patients of physicians who provided a higher percentage of virtual care did not have higher ED visit rates compared with patients of physicians who provided the lowest levels of virtual care. The findings refute the hypothesis that family physicians providing more care virtually during the pandemic resulted in higher ED use.

Higher Neighborhood Drivability Is Associated With a Higher Diabetes Risk in Younger Adults: A Population-Based Cohort Study in Toronto, Canada

OBJECTIVE

Car dependency contributes to physical inactivity and, consequently, may increase the likelihood of diabetes. We investigated whether neighborhoods that are highly conducive to driving confer a greater risk of developing diabetes and, if so, whether this differs by age.

RESEARCH DESIGN AND METHODS

We used administrative healthcare data to identify all working-age Canadian adults (20-64 years) who were living in Toronto on 1 April 2011 without diabetes (type 1 or 2). Neighborhood drivability scores were assigned using a novel, validated index that predicts driving patterns based on built environment features divided into quintiles. Cox regression was used to examine the association between neighborhood drivability and 7-year risk of diabetes onset, overall and by age-group, adjusting for baseline characteristics and comorbidities.

RESULTS

Overall, there were 1,473,994 adults in the cohort (mean age 40.9 ± 12.2 years), among whom 77,835 developed diabetes during follow-up. Those living in the most drivable neighborhoods (quintile 5) had a 41% higher risk of developing diabetes compared with those in the least drivable neighborhoods (adjusted hazard ratio 1.41, 95% CI 1.37-1.44), with the strongest associations in younger adults aged 20-34 years (1.57, 95% CI 1.47-1.68, P < 0.001 for interaction). The same comparison in older adults (55-64 years) yielded smaller differences (1.31, 95% CI 1.26-1.36). Associations appeared to be strongest in middle-income neighborhoods for younger residents (middle income 1.96, 95% CI 1.64-2.33) and older residents (1.46, 95% CI 1.32-1.62).

CONCLUSIONS

High neighborhood drivability is a risk factor for diabetes, particularly in younger adults. This finding has important implications for future urban design policies.

Understanding sex-related differences in healthcare utilisation among patients with inflammatory arthritis: a population-based study

OBJECTIVES

Our aim was to compare patterns of musculoskeletal-related healthcare utilisation between male and female patients before and after the diagnosis of inflammatory arthritis (IA).

METHODS

We used Ontario administrative health data to create three inception cohorts of adult patients with rheumatoid arthritis (RA), ankylosing spondylitis (AS) and psoriatic arthritis (PsA) diagnosed between April 2010 and March 2017. Healthcare utilisation indicators including visits to physicians, and use of musculoskeletal imaging and laboratory tests were assessed in each year for 3 years before and after diagnosis and compared between male and female patients using regression models adjusting for sociodemographic factors and comorbidities. Results were reported as ORs with 95% CIs for female patients compared with male patients.

RESULTS

A total of 41 277 patients with RA (69% female), 8150 patients with AS (51% female) and 6446 patients with PsA (54% female) were analysed.Similar trends of sex-related differences were observed in all three cohorts. Before diagnosis, female patients were more likely to visit rheumatologists (OR 1.32-2.28) and family physicians (OR 1.03-1.15) for musculoskeletal reasons, whereas male patients were more likely to visit the emergency for musculoskeletal reasons (OR 0.76-0.87). A similar female predominance was observed regarding musculoskeletal imaging and laboratory tests before diagnosis. After diagnosis, female patients were more likely to remain in rheumatology care (OR 1.12-1.24).

CONCLUSION

Female patients with IA have higher healthcare utilisation than male patients which may indicate biological differences in disease course or sociocultural differences in healthcare-seeking behaviour.

Trends in health service use among persons with Parkinson's disease by rurality: A population-based repeated cross-sectional study

BACKGROUND

The global burden of Parkinson's disease (PD) has more than doubled over the past three decades, and this trend is expected to continue. Despite generally poorer access to health care services in rural areas, little previous work has examined health system use in persons with PD by rurality. We examined trends in the prevalence of PD and health service use among persons with PD by rurality in Ontario, Canada.

METHODS

We conducted a repeated, cross-sectional analysis of persons with prevalent PD aged 40+ years on April 1st of each year from 2000 to 2018 using health administrative databases and calculated the age-sex standardized prevalence of PD. Prevalence of PD was also stratified by rurality and sex. Negative binomial models were used to calculate rate ratios with 95% confidence intervals comparing rates of health service use in rural compared to urban residents in 2018.

RESULTS

The age-sex standardized prevalence of PD in Ontario increased by 0.34% per year (p<0.0001) and was 459 per 100,000 in 2018 (n = 33,479), with a lower prevalence in rural compared to urban residents (401 vs. 467 per 100,000). Rates of hospitalizations and family physician visits declined over time in both men and women with PD in rural and urban areas, while rates of emergency department, neurologist, and other specialist visits increased. Adjusted rates of hospitalizations were similar between rural and urban residents (RR = 1.04, 95% CI [0.96, 1.12]), while rates of emergency department visits were higher among rural residents (RR = 1.35, 95% CI [1.27, 1.42]). Rural residents had lower rates of family physician (adjusted RR = 0.82, (95% CI [0.79, 0.84]) and neurologist visits (RR = 0.74, 95% CI [0.72, 0.77]).

INTERPRETATION

Lower rates of outpatient health service use among persons residing in rural regions, contrasting with higher rates of emergency department visits suggest inequities in access. Efforts to improve access to primary and specialist care for persons with PD in rural regions are needed.

Family Physicians Stopping Practice During the COVID-19 Pandemic in Ontario, Canada

We conducted 2 analyses using administrative data to understand whether more family physicians in Ontario, Canada stopped working during the COVID-19 pandemic compared with previous years. First, we found 3.1% of physicians working in 2019 (n = 385/12,247) reported no billings in the first 6 months of the pandemic; compared with other family physicians, a higher portion were aged 75 years or older (13.0% vs 3.4%, P <0.001), had fee-for-service reimbursement (37.7% vs 24.9%, P <0.001), and had a panel size under 500 patients (40.0% vs 25.8%, P <0.001). Second, a fitted regression line found the absolute increase in the percentage of family physicians stopping work was 0.03% per year from 2010 to 2019 (P = 0.042) but 1.2% between 2019 to 2020 (P <0.001). More research is needed to understand the impact of physicians stopping work on primary care attachment and access to care.

The mean attributable health care costs associated with hepatitis B virus in Ontario, Canada: A matched cohort study

BACKGROUND: No Canadian studies examined the economic impact of hepatitis B virus (HBV) using population-based, patient-level data. We determined attributable costs associated with HBV from a health care payer perspective. METHODS: We conducted an incidence-based, matched cohort, cost-of-illness study. We identified infected subjects (positive HBV surface antigen, DNA, or e-antigen) between 2004 and 2014, using health administrative data. The index date was the first positive specimen. The cohort was organized into three groups: no HBV-related complications, HBV-related complications before index date, and HBV-related complications post-index date. To evaluate costs (2017 Canadian dollars), we adopted the phase-of-care approach defining six phases. Mean attributable costs were determined by evaluating mean differences between matched pairs. Hard match variables were sex, age group, index year, rurality, neighbourhood income quintile, comorbidities, and immigrant status. Costs were combined with crude survival data to calculate 1-, 5-, and 10-year costs. RESULTS: We identified 41,469 infected subjects with a mean age of 44.2 years. The majority were males (54.7%), immigrants (58.4%), and residents of major urban centres (96.8%). Eight percent had HBV-related complications before index date and 11.5% had them post index date. Across groups, mean attributable costs ranged from CAD-$27–$19 for pre-diagnosis, CAD$167–$1,062 for initial care, CAD$53–$407 for continuing care, CAD$1,033 for HBV-related complications, $304 for continuing care for complications, and CAD$2,552–$4,281 for final care. Mean cumulative 1-, 5-, and 10-year costs ranged between CAD$253–$3,067, $3,067–$20,349, and CAD$6,128–$38,968, respectively. CONCLUSIONS: HBV is associated with long-term economic burden. These results support decision-making on HBV prevention and monitoring strategies.

[Effects of interpregnancy interval on pregnancy outcomes of subsequent pregnancy: a multicenter retrospective study]

Objective: To explore the effects of interpregnancy interval (IPI) on pregnancy outcomes of subsequent pregnancy. Methods: A multicenter retrospective study was conducted in 21 hospitals in China. Information of age, height, pre-pregnancy weight, IPI, history of diseases, complications of pregnancy, gestational age of delivery, delivery mode, and pregnancy outcomes of the participants were collected by consulting medical records of pregnant women who had two consecutive deliveries in the same hospital during 2011 to 2018. The participants were divided into 4 groups according to IPI:<18 months, 18-23 months, 24-59 months and ≥60 months. According to the WHO's recommendation, with the IPI of 24-59 months group as a reference, to the effects of IPI on pregnancy outcomes of subsequent pregnancy were analyzed. Stratified analysis was further carried out based on age, history of gestational diabetes mellitus (GDM), macrosomia, and premature delivery, to explore the differences in the effects of IPI on pregnancy outcomes among women with different characteristics. Results: A total of 8 026 women were included in this study. There were 423, 623, 5 512 and 1 468 participants in <18 months group, 18-23 months group, 24-59 months group and ≥60 months group, respectively. (1) The age, pre-pregnancy body mass index (BMI), history of cesarean section, GDM, gestational hypertension and cesarean section delivery rate of <18 months group, 18-23 months group, 24-59 months group and ≥60 months group were gradually increased, and the differences were statistically significant (P<0.05). (2) After adjusting for potential confounding factors, compared with women in the IPI of 24-59 months group, the risk of premature delivery, premature rupture of membranes, and oligohydramnios were increased by 42% (OR=1.42, 95%CI: 1.07-1.88, P=0.015), 46% (OR=1.46, 95%CI: 1.13-1.88, P=0.004), and 64% (OR=1.64, 95%CI: 1.13-2.38, P=0.009) respectively for women in the IPI≥60 months group. No effects of IPI on other pregnancy outcomes were found in this study (P>0.05). (3) After stratified by age and adjusted for confounding factors, compared with women in the IPI of 24-59 months group, IPI≥60 months would significantly increase the risk of oligohydramnios for women with advanced age (OR=2.87, 95%CI: 1.41-5.83, P=0.004); and <18 months could increase the risk of premature rupture of membranes for women under the age of 35 (OR=1.59, 95%CI: 1.04-2.43, P=0.032). Both the risk of premature rupture of membranes (OR=1.58, 95%CI: 1.18-2.13, P=0.002) and premature delivery (OR=1.52, 95%CI: 1.07-2.17, P=0.020) were significantly increased in the IPI≥60 months group. After stratified by history of GDM and adjusted for confounding factors, compared with women in the IPI of 24-59 months group, IPI≥60 months would lead to an increased risk of postpartum hemorrhage for women with a history of GDM (OR=5.34, 95%CI: 1.45-19.70, P=0.012) and an increased risk of premature rupture of membranes for women without a history of GDM (OR=1.44, 95%CI: 1.10-1.90, P=0.009). After stratified by history of macrosomia and adjusted for confounding factors, compared with women in the IPI of 24-59 months group, IPI≥60 months could increase the proportion of cesarean section for women with a history of macrosomia (OR=4.11, 95%CI: 1.18-14.27, P=0.026) and the risk of premature rupture of membranes for women without a history of macrosomia (OR=1.46, 95%CI: 1.12-1.89, P=0.005). After stratified by history of premature delivery and adjusted for confounding factors, compared with women in the IPI of 24-59 months group, IPI≥60 months would significantly increase the risk of premature rupture of membranes for women without a history of premature delivery (OR=1.47, 95%CI: 1.13-1.92, P=0.004). Conclusions: Both IPI≥60 months and <18 months would increase the risk of adverse pregnancy outcomes in the subsequent pregnancy. Healthcare education and consultation should be conducted for women of reproductive age to maintain an appropriate IPI when they plan to pregnant again, to reduce the risk of adverse pregnancy outcomes in the subsequent pregnancy.

The Canadian Alliance for Healthy Hearts and Minds: How Well Does It Reflect the Canadian Population?

BACKGROUND

The intent of the Canadian Alliance for Healthy Hearts and Minds (CAHHM) cohort is to understand the early determinants of subclinical cardiac and vascular disease and progression in adults selected from existing cohorts-the Canadian Partnership for Tomorrow's Health, the Prospective Urban and Rural Evaluation (PURE) cohort, and the Montreal Heart Institute Biobank. We evaluated how well the CAHHM-Health Services Research (CAHHM-HSR) subcohort reflects the Canadian population.

METHODS

A cross-sectional design was used among a prospective cohort of community-dwelling adults aged 35-69 years who met the CAHHM inclusion criteria, and a cohort of adults aged 35-69 years who responded to the 2015 Canadian Community Health Survey-Rapid Response module. The INTERHEART risk score was calculated at the individual level with means and proportions reported at the overall and provincial level.

RESULTS

There are modest differences between CAHHM-HSR study participants and the 2015 Canadian Community Health Survey-Rapid Response respondents in age (56.3 vs 51.7 mean years), proportion of men (44.9% vs 49.3%), and mean INTERHEART risk score (9.7 vs 10.1). Larger differences were observed in postsecondary education (86.8% vs 70.2%), Chinese ethnicity (11.0% vs 3.3%), obesity (23.2% vs 29.3%), current smoker status (6.1% vs 18.4%), and having no cardiac testing (30.4% vs 55.9%).

CONCLUSIONS

CAHHM-HSR participants are older, of higher socioeconomic status, and have a similar mean INTERHEART risk score, compared with participants in the Canadian Community Health Survey. Differing sampling strategies and missing data may explain some differences between the CAHHM-HSR cohort and Canadian community-dwelling adults and should be considered when using the CAHHM-HSR for scientific research.

Universal Drug Coverage and Socioeconomic Disparities in Health Care Costs Among Persons With Diabetes

OBJECTIVE

To examine whether neighborhood socioeconomic status (SES) is a predictor of non-drug-related health care costs among Canadian adults with diabetes and, if so, whether SES disparities in costs are reduced after age 65 years, when universal drug coverage commences as an insurable benefit.

RESEARCH DESIGN AND METHODS

Administrative health databases were used to examine publicly funded health care expenditures among 698,113 younger (20-64 years) and older (≥65 years) adults with diabetes in Ontario from April 2004 to March 2014. Generalized linear models were constructed to examine relative and absolute differences in health care costs (total and non-drug-related costs) across neighborhood SES quintiles, by age, with adjustment for differences in age, sex, diabetes duration, and comorbidity.

RESULTS

Unadjusted costs per person-year in the lowest SES quintile (Q1) versus the highest (Q5) were 39% higher among younger adults ($5,954 vs. $4,270 [Canadian dollars]) but only 9% higher among older adults ($10,917 vs. $9,993). Adjusted non-drug costs (primarily for hospitalizations and physician visits) were $1,569 per person-year higher among younger adults in Q1 vs. Q5 (modeled relative cost difference: 35.7% higher) and $139.3 million per year among all individuals in Q1. Scenarios in which these excess costs per person-year were decreased by ≥10% or matched the relative difference among seniors suggested a potential for savings in the range of $26.0-$128.2 million per year among all lower-SES adults under age 65 years (Q1-Q4).

CONCLUSIONS

SES is a predictor of diabetes-related health care costs in our setting, more so among adults under age 65 years, a group that lacks universal drug coverage under Ontario's health care system. Non-drug-related health care costs were more than one-third higher in younger, lower-SES adults, translating to >$1 billion more in health care expenditures over 10 years.

[PARP10 Influences the Proliferation of Colorectal Carcinoma Cells, a Preliminary Study]

PARP10 is an intracellular mono-ADP ribosyltransferase and recent reports suggest that it regulates proliferation of some cell types. However, its effect on the proliferation of colorectal carcinoma cells has not yet been systematically reported. We explored the influence of PARP10 on the proliferation of several colorectal carcinoma cell types and carried out initial studies on the underlying mechanisms. Inhibition of the enzymatic activity of PARP10 led to significantly decreases in proliferative ability in LoVo cells and CT26 cells in vitro and suppressed growth of CT26 tumours in the subaxilliary region in Balb/c mice in vivo. Cell-cycle arrest accompanied these observations. Expression of the nuclear transfer factor β-catenin and it trans-location to the nucleus were also affected and the expression of its associated signal proteins Axin2 and c-Myb were increased and decreased, respectively. We demonstrate that PARP10 promotes proliferation of those colorectal carcinoma cells which express significant levels of PARP10. This promotion is suppressed when the enzymatic activity is inhibited. β-Catenin is likely to be the mediator of the antiproliferative effect.

[Safety evaluation on different ventilation strategies set for neonatal respiratory distress syndrome: a network Meta-analysis]

Objective: To evaluate the relative safety of different ventilation methods regarding mortality and rates of complication, on neonatal respiratory distress syndrome (NRDS). Methods: Network Meta-analysis was used to collect data on randomized controlled trials of pulmonary ventilation strategies in preterm infants with a mean gestational age of less than 32 weeks. Diagnostic criteria on NRDS were published in the PubMed, Cochrane, Web of Science, EBSCO, and Springer Link databases from January 1986 to June 2018. Revman 5.3 software was used to evaluate the quality of studies, based on the Cochrane quality assessment tool. Data were analyzed by Bayesian and frequency methods, using both Win BUGS 1.4.3 and STATA 13.0 software. Safety of different ventilation strategies for NRDS mortality and complications would include intraventricular hemorrhage (IVH), patent ductus arteriosus (PDA) and retinopathy of prematurity (ROP) and were evaluated. Counted data was displayed by OR and 95%CI. Results: A total of 31 RCTs were included in this paper, including 5 827 preterm infants and 11 ventilation strategies. There were no statistically significant differences appearing in 11 ventilation strategies on mortality, PDA or ROP. IVH results were reported in 28 studies. Compared with nasal intermittent positive pressure ventilation (NIPPV), both high- frequency oscillation ventilation (HFOV) (OR=3.33, 95%CI: 1.08-16.67, P<0.05) and synchronized intermittent mechanical ventilation (SIMV) (OR=8.22, 95%CI: 1.25-29.44, P<0.05) schemes seemed to have increased the risk of IVH in preterm infants with NRDS. NIPPV appeared the optimal ventilation strategy in the rankings of cumulative probability. Results on clustering showed that NIPPV was probably the best ventilation strategy for children with NRDS after considering the orders of IVH, PDA and ROP on mortality, respectively. However, HFOV, IMV, and SIMV did not seem to be the ideal ventilated strategies. Conclusions: Most of the clinical decision makers might prefer using NIPPV in the treatment of children with NRDS through mechanical ventilation systems to reduce both the incidence and death caused by IVH, PDA and ROP. It was not recommended to use HFOV, SIMV and IMV in treating NRDS with gestational less than 32 weeks. We suggested that larger numbers of multi-center RCTs ba carried out to make the above conclusions more convincing.

Comparing the high-dimensional propensity score for use with administrative data with propensity scores derived from high-quality clinical data

Administrative healthcare databases are increasingly being used for research purposes. When used to estimate the effects of treatments and interventions, an important limitation of these databases is the lack of information on important confounding variables. The high-dimensional propensity score (hdPS) is an algorithm that generates a large number of empirically-derived covariates using administrative healthcare databases. The hdPS has been described as enabling adjustment by proxy, in which a large number of empirically-derived covariates may serve as proxies for unmeasured confounding variables. We examined the validity of this assumption using samples of patients hospitalized with acute myocardial infarction (AMI) and congestive heart failure (CHF), for whom both administrative data and detailed clinical data were available. We considered three treatments in AMI patients: angiotensin-converting enzyme inhibitors, beta-blockers, and statins, while the first two treatments were also considered in CHF patients. We considered three propensity scores: (a) one derived using detailed clinical data; (b) the hdPS derived from administrative data; and (c) one derived from administrative data using expert opinion. Using each propensity score, we estimated inverse probability of treatment (IPT) weights. For each sample and treatment combination, and for each of the two propensity scores derived using administrative data, there were clinical variables not measured in administrative data that remained imbalanced after incorporating the IPT weights. However, the propensity score derived using clinical data always resulted in all clinical variables being balanced. When estimating hazard ratios, for some samples and treatment combinations, the hazard ratios estimated using the hdPS were more similar to those obtained using the clinical propensity score than were those obtained using the expert-derived propensity score. However, for other combinations, the effects estimated using the expert-derived propensity score were more similar to those obtained using the clinical propensity score than were those derived using the hdPS.

[General plan of Shanghai Diet and Health Survey]

Shanghai Diet and Health Survey (SDHS) was designed to prospectively access local residents' food consumption, energy and nutrient intake, related chemical contaminant exposure, and the seasonal change trend to explore the relationship of diet with health. Data from SDHS can be used as fundamental information and scientific evidences for the development of local nutrition and food safety policies.

Partial Recovery of Mitochondrial Function of Vitrified Porcine MII Stage Oocytes During Post-Thaw Incubation

　　The survival of porcine oocytes is still very low after cryopreservation.

OBJECTIVE

To investigate whether and when the mitochondrial function of vitrified porcine oocytes could be recovered post-thaw.

MATERIALS AND METHODS

Mitochondrial potential, ROS level, ATP content, apoptotic rate, caspase activity, and parthenogenetics developmental ability of thawed porcine oocytes were measured after culture in vitro for 0, 1, 2 or 4 h.

RESULTS

Mitochondrial potential after 2 h and 4 h post-thaw culture were 1.19 and 1.26, significantly lower than that of fresh oocytes but much higher than the groups cultured for 0 h and 1 h (P<0.05). Cryopreservation increased the ROS level in oocytes considerably, which decreased only after 2 to 4 h incubation following thaw. ATP content increased gradually over time and recovered to the level comparable to that of fresh oocytes after 4 h. Pan caspase levels increased after cryopreservation and reached the highest level at 1 h incubation. Thereafter it decreased to a low value, but still higher than fresh oocytes. Oocytes showing an early apoptotic event decreased upon 2 to 4 h incubation. The parthenogenetic cleavage and blastocyst rates were the highest (19.8% and 5.6%) after 2 h incubation.

CONCLUSION

The recovery of mitochondrial function could complete after 2 to 4 h post-thaw incubation. Post-thaw incubation for 2 to 4 h reduced apoptotic events and improved parthenogenetic developmental ability of vitrified porcine MII stage oocytes.

Phase noise reduction by optical phase-locked loop for a coherent bichromatic laser based on the injection-locking technique

We present a coherent bichromatic laser system with low phase noise. An optical injection process is used to generate coherent laser beams with a frequency difference of 9.192 631 77 GHz using an electro-optical modulator. An optical phase-locked loop is then applied to reduce the phase noise. The phase noise of the beat note is -41, -81, -98, -83, and -95 dBrad²/Hz at the offset frequencies of 1 Hz, 100 Hz, 1 kHz, 10 kHz, and 1 MHz, respectively. Compared to a system that uses optical injection alone, the phase noise is reduced by up to 20-30 dB in the low-frequency range, and the intermodulation effect on the continuous atomic clock is reduced by an order of magnitude. This configuration can adjust the intensities and polarizations of the laser beams independently and reduce the phase noise caused by environmental disturbances and optical injection, which may be useful for application to atomic coherence experiments.

[Effects of rabbit adipose-derived mesenchymal stem cells on the healing of skin deep partial-thickness scald wound of rabbit]

OBJECTIVE

To investigate the effects of local injection of rabbit adipose-derived mesenchymal stem cells (ADSCs) on the healing of skin deep partial-thickness scald wound of rabbit.

METHODS

ADSCs were isolated from adipose tissue of one New Zealand rabbit and then sub-cultured. ADSCs of the third passage were used in the following experiments. Twenty-four rabbits were divided into ADSCs group (n=12) and control group (n=12) according to the random number table, and one deep partial-thickness scald wound with diameter of 5 cm on the two sides of the back near the buttocks was made. From post injury day (PID) 2, 2 mL suspension of EdU-labeled ADSCs with the number of 5×10(5) per mL was subcutaneously injected in wounds of rabbits in ADSCs group, while the rabbits in control group were given 2 mL serum-free DMEM until the wounds were healed. Wound healing processes of rabbits in two groups were observed every day, and the healing time was recorded. On PID 7, 14, 21, and 28, areas of wound of three rabbits in two groups were measured and the healing rates were calculated, respectively. The healed wound tissue was harvested to observe the morphology by HE staining, and the expression of collagen fiber was observed by Masson staining. The distribution of EdU-labeled ADSCs in healed wound tissue on PID 28 was observed by inverted fluorescence microscope. The expressions of vascular endothelial growth factor (VEGF) and epidermal growth factor (EGF) of healed wound tissue on PID 7, 14, and 21 were detected by enzyme-linked immunosorbent assay. Data were processed with analysis of variance of factorial design and paired samples t test.

RESULTS

(1) The wound healing time of rabbits in ADSCs group was (19.5±1.1) d post injury, which was significantly shorter than that in control group [(23.3±1.5) d, t=4.50, P<0.05]. On PID 7, wounds of rabbits in two groups were dry with no obvious exudation, and redness and swelling around wounds disappeared gradually, the wound healing rate of rabbits in ADSCs group was (15.1±2.4)%, which was close to that in control group [(13.7±3.1)%, t=1.20, P>0.05]. On PID 14, wounds of rabbits in ADSCs group were dry and scabbed obviously, and the wound healing rate was (73.1±5.7)%, while wounds of rabbits in control group were little scabbed with little exudation, and the wound healing rate was significantly lower than that in ADSCs group [(52.9±5.1)%, t=8.06, P<0.01]. On PID 21, wounds of rabbits in ADSCs group were generally healed, and the wound healing rate was (95.6±3.0)%, while a few wounds still existed in rabbits of control group, and the wound healing rate was significantly lower than that in ADSCs group [(78.6±3.7)%, t=9.73, P<0.01]. On PID 28, wounds of rabbits in two groups were totally healed with the healing rate of 100%, and texture and microvascular responses of healed wound tissue in ADSCs group were better than those in control group. (2) On PID 7, fibroblasts in healed wound tissue of rabbits in two groups were all increased, and there were little vascular and collagen fiber proliferation with no obvious differences. On PID 14, the number of fibroblasts in healed wound tissue of rabbits in ADSCs group was more than that in control group, and the collagen fibers in healed wound tissue of rabbits in ADSCs group were arranged in dense and uniform, while those in control group were sparse and irregular. On PID 21, skin layers were differentiated in healed wound tissue of rabbits in two groups, and collagen fibers in healed wound tissue of rabbits in ADSCs group were still denser than that in control group. On PID 28, newborn skin was well differentiated in healed wound tissue of rabbits in ADSCs group, which was better than that in control group. There were a lot of thick collagen fibers in healed wound tissue of rabbits in two groups, and EdU-labeled ADSCs were involved in skin texture of rabbits in ADSCs group. (3) The expressions of VEGF and EGF in healed wound tissue of rabbits in two groups were similar on PID 7 (with t values respectively 0.70 and 0.91, P values above 0.05), which in ADSCs group were significantly higher than those in control group on PID 14 and 21 (with t values from 2.85 to 4.81, P values below 0.01).

CONCLUSIONS

The transplantation of ADSCs can promote the wound healing of skin deep partial-thickness scald wound of rabbit and shorten the wound healing time.

Impact of pedicle-lengthening osteotomy on spinal canal volume and neural foramen size in three types of lumbar spinal stenosis

Objectives

Pedicle-lengthening osteotomy is a novel surgery for lumbar spinal stenosis (LSS), which achieves substantial enlargement of the spinal canal by expansion of the bilateral pedicle osteotomy sites. Few studies have evaluated the impact of this new surgery on spinal canal volume (SCV) and neural foramen dimension (NFD) in three different types of LSS patients.

Methods

CT scans were performed on 36 LSS patients (12 central canal stenosis (CCS), 12 lateral recess stenosis (LRS), and 12 foraminal stenosis (FS)) at L4-L5, and on 12 normal (control) subjects. Mimics 14.01 workstation was used to reconstruct 3D models of the L4-L5 vertebrae and discs. SCV and NFD were measured after 1 mm, 2 mm, 3 mm, 4 mm, or 5 mm pedicle-lengthening osteotomies at L4 and/or L5. One-way analysis of variance was used to examine between-group differences.

Results

In the intact state, SVC and NFD were significantly larger in the control group compared with the LSS groups (P<0.05). After lengthening at L4, the percentage increase in SCV (per millimetre) was LRS>CCS>FS>Control. After lengthening at L5 and L4-L5, the percentage increase in SCV (per millimetre) was LRS>FS>CCS>Control. After lengthening at L4 and L4-L5, the percentage increase in NFD (per millimetre) was FS>CCS>LRS>Control. After lengthening at L5, the percentage increase in NFD (per millimetre) was CCS>LRS>control>FS.

Conclusions

LRS patients are the most suitable candidates for treatment with pedicle-lengthening osteotomy. Lengthening L4 pedicles produced larger percentage increases in NFD than lengthening L5 pedicles (p < 0.05). Lengthening L4 pedicles may be the most effective option for relieving foraminal compression in LSS patients.

Cite this article: P. Li, L. Qian, W. D. Wu, C. F. Wu, J. Ouyang. Impact of pedicle-lengthening osteotomy on spinal canal volume and neural foramen size in three types of lumbar spinal stenosis. Bone Joint Res 2016;5:239–246. DOI: 10.1302/2046-3758.56.2000469.

Both death receptor and mitochondria mediated apoptotic pathways participated the occurrence of apoptosis in porcine vitrified mii stage oocytes

BACKGROUND

Oocytes vitrification is widely used for cryopreservation of female genetic resources.

OBJECTIVE

In order to illuminate the apoptotic pathways of porcine MII stage oocytes after vitrification.

MATERIALS AND METHODS

This study used in situ fluorescence staining and RT-PCR to detect the expression levels of some key molecules from death receptor and mitochondria mediated apoptotic pathways.

RESULTS

(1) Early stage apoptosis were detected in both PI staining survival oocytes and PI staining dead oocytes. (2) The fluorescence intensity of caspase 8, caspase 9, caspase 3 and pan caspase from vitrified oocytes were 32.03, 16.56, 16.70 and 8.43 respectively, which were much higher than those from fresh oocytes (4.02, 4.83, 4.23 and 3.08, P < 0.05). (3) Not only the genes from death receptor mediated apoptotic pathway, but also from mitochondrial mediated apoptotic pathway were changed greatly.

CONCLUSION

The death of porcine vitrified oocytes could be induced by apoptosis, both death receptor and mitochondria mediated apoptotic pathways participated the occurrence of apoptosis in porcine vitrified MII stage oocytes.

Short-term risk of cancer among women with previous gestational diabetes: a population-based study

AIMS

To evaluate the relationship between gestational diabetes (GDM) and incidence of cancer in women within the first decade postpartum.

METHODS

This population-based retrospective cohort study compared the risk of cancer in women with GDM with that of a matched control group comprising pregnant women without diabetes. We included women from Ontario, Canada aged 20-50 years with no history of cancer who had given birth between 1995 and 2008 (N = 149 049). Women with GDM (N = 49 684) were matched on age and year of giving birth, in a ratio of 1:2, to pregnant women without diabetes (N = 99 365).

RESULTS

Over a median 8-year follow-up, there were a total of 2927 (1.5%) cancers. After adjustment for covariates, we found no significant difference in overall risk of cancer between women with GDM and matched control subjects; however, GDM was associated with a significantly greater risk of thyroid cancer (adjusted hazard ratio 1.24, 95% CI 1.05, 1.46) and a significantly lower risk of premenopausal breast cancer (hazard ratio 0.86, 95% CI 0.75, 0.98) compared with matched control subjects.

CONCLUSIONS

This large population-based study did not find a greater risk of cancers among women with GDM during the first decade postpartum; however, GDM was associated with a higher risk of thyroid cancer and a lower risk of premenopausal breast cancer. Further studies are needed to confirm these findings.

Expression of macrophage migration-inhibitory factor in duodenal ulcer and its relation to Helicobacter pylori infection

The aim of this study was to examine the expression of macrophage migration-inhibitory factor (MIF) in duodenal ulcer epithelial cells and its relation to Helicobacter pylori (Hp) infection, and to discuss the pathogenic roles of MIF expression and Hp infection in duodenal ulcer. MIF protein and mRNA expression was examined in samples from patients with duodenal ulcer with and without Hp infection (N = 40 each, experimental group), and in normal duodenal bulb mucosal tissue (N = 40, control group) using immunohistochemistry and in situ hybridization. Patients without Hp infection received routine treatment, and treatment was provided to the patients positive for Hp to eradicate Hp infection. Hp and MIF expression levels before treatment and after the ulcer had been cured were compared. The positive rates of MIF protein and mRNA in patients with Hp infection before treatment were 67.5 and 65%, respectively, and were 18.9 and 21.6% in the 37 patients from whom Hp was eliminated. These were statistically different both before and after treatment compared with controls (P < 0.05). In the patients without Hp infection, the positive rates of MIF protein and mRNA expression before (45 and 47.5%, respectively) and after (32.5 and 30%) treatment were not significantly different (P > 0.05). The results of this study suggested that MIF is related to the development of duodenal ulcer, and that the presence of Hp is closely related with the expression of MIF in the duodenal mucosa and the development of duodenal ulcer.

A coupled "AB" system: Rogue waves and modulation instabilities

Rogue waves are unexpectedly large and localized displacements from an equilibrium position or an otherwise calm background. For the nonlinear Schrödinger (NLS) model widely used in fluid mechanics and optics, these waves can occur only when dispersion and nonlinearity are of the same sign, a regime of modulation instability. For coupled NLS equations, rogue waves will arise even if dispersion and nonlinearity are of opposite signs in each component as new regimes of modulation instability will appear in the coupled system. The same phenomenon will be demonstrated here for a coupled "AB" system, a wave-current interaction model describing baroclinic instability processes in geophysical flows. Indeed, the onset of modulation instability correlates precisely with the existence criterion for rogue waves for this system. Transitions from "elevation" rogue waves to "depression" rogue waves are elucidated analytically. The dispersion relation as a polynomial of the fourth order may possess double pairs of complex roots, leading to multiple configurations of rogue waves for a given set of input parameters. For special parameter regimes, the dispersion relation reduces to a cubic polynomial, allowing the existence criterion for rogue waves to be computed explicitly. Numerical tests correlating modulation instability and evolution of rogue waves were conducted.

Unintentional Discontinuation of Chronic Medications for Seniors in Nursing Homes: Evaluation of a National Medication Reconciliation Accreditation Requirement Using a Population-Based Cohort Study

Transitions of care leave patients vulnerable to the unintentional discontinuation of medications with proven efficacy for treating chronic diseases. Older adults residing in nursing homes may be especially susceptible to this preventable adverse event. The effect of large-scale policy changes on improving this practice is unknown.The objective of this study was to analyze the effect of a national medication reconciliation accreditation requirement for nursing homes on rates of unintentional medication discontinuation after hospital discharge.It was a population-based retrospective cohort study that used linked administrative records between 2003 and 2012 of all hospitalizations in Ontario, Canada. We identified nursing home residents aged ≥66 years who had continuous use of ≥1 of the 3 selected medications for chronic disease: levothyroxine, HMG-CoA reductase inhibitors (statins), and proton pump inhibitors (PPIs).In 2008 medication reconciliation became a required practice for accreditation of Canadian nursing homes.The main outcome measures included the proportion of patients who restarted the medication of interest after hospital discharge at 7 days. We also performed a time series analysis to examine the impact of the accreditation requirement on rates of unintentional medication discontinuation.The study included 113,088 adults aged ≥66 years who were nursing home residents, had an acute hospitalization, and were discharged alive to the same nursing home. Overall rates of discontinuation at 7-days after hospital discharge were highest in 2003-2004 for all nursing homes: 23.9% for thyroxine, 26.4% for statins, and 23.9% for PPIs. In most of the cases, these overall rates decreased annually and were lowest in 2011-2012: 4.0% for thyroxine, 10.6% for statins, and 8.3% for PPIs. The time series analysis found that nursing home accreditation did not significantly lower medication discontinuation rates for any of the 3 drug groups.From 2003 to 2012, there were marked improvements in rates of unintentional medication discontinuation among hospitalized older adults who were admitted from and discharged to nursing homes. This change was not directly associated with the new medication reconciliation accreditation requirement, but the overall improvements observed may have been reflective of multiple processes and not 1 individual intervention.

Gender differences in the impact of poverty on health: disparities in risk of diabetes-related amputation

AIMS

To assess the combined impact of socio-economic status and gender on the risk of diabetes-related lower extremity amputation within a universal healthcare system.

METHODS

We conducted a population-based cohort study using administrative health databases from Ontario, Canada. Adults with pre-existing or newly diagnosed diabetes (N = 606 494) were included and the incidence of lower extremity amputation was assessed for the period 1 April 2002 to 31 March 2009. Socio-economic status was based on neighbourhood-level income groups, assigned to individuals using the Canadian Census and their postal code of residence.

RESULTS

Low socio-economic status was associated with a significantly higher incidence of lower extremity amputation (27.0 vs 19.3 per 10,000 person-years in the lowest (Q1) vs the highest (Q5) socio-economic status quintile. This relationship persisted after adjusting for primary care use, region of residence and comorbidity, and was greater among men (adjusted Q1:Q5 hazard ratio 1.41, 95% CI 1.30-1.54; P < 0.0001 for all male gender-socio-economic status interactions) than women (hazard ratio 1.20, 95% CI 1.06-1.36). Overall, the incidence of lower extremity amputation was higher among men than women (hazard ratio for men vs women: 1.87, 95% CI 1.79-1.96), with the greatest disparity between men in the lowest socio-economic status category and women in the highest (hazard ratio 2.39, 95% CI 2.06-2.77 and hazard ratio 2.30, 95% CI 1.97-2.68, for major and minor amputation, respectively).

CONCLUSIONS

Despite universal access to hospital and physician care, we found marked socio-economic status and gender disparities in the risk of lower extremity amputation among patients with diabetes. Men living in low-income neighbourhoods were at greatest risk.

Neighborhood socioeconomic status and barriers to peritoneal dialysis: a mixed methods study

BACKGROUND AND OBJECTIVES

The objective of this study was to evaluate the association between neighborhood socioeconomic status and barriers to peritoneal dialysis eligibility and choice.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This study was a mixed methods parallel design study using quantitative and qualitative data from a prospective clinical database of ESRD patients. The eligibility and choice cohorts were assembled from consecutive incident chronic dialysis patients entering one of five renal programs in the province of Ontario, Canada, between January 1, 2004 and December 31, 2010. Socioeconomic status was measured as median household income and percentage of residents with at least a high school education using Statistics Canada dissemination area-level data. Multivariable models described the relationship between socioeconomic status and likelihood of peritoneal dialysis eligibility and choice. Barriers to peritoneal dialysis eligibility and choice were classified into qualitative categories using the thematic constant comparative approach.

RESULTS

The peritoneal dialysis eligibility and choice cohorts had 1314 and 857 patients, respectively; 65% of patients were deemed eligible for peritoneal dialysis, and 46% of eligible patients chose peritoneal dialysis. Socioeconomic status was not a significant predictor of peritoneal dialysis eligibility or choice in this study. Qualitative analyses identified 16 barriers to peritoneal dialysis choice. Patients in lower- versus higher-income Statistics Canada dissemination areas cited built environment or space barriers to peritoneal dialysis (4.6% versus 2.7%) and family or social support barriers (8.3% versus 3.5%) more frequently.

CONCLUSIONS

Peritoneal dialysis eligibility and choice were not associated with socioeconomic status. However, socioeconomic status may influence specific barriers to peritoneal dialysis choice. Additional studies to determine the effect of targeting interventions to specific barriers to peritoneal dialysis choice in low socioeconomic status patients on peritoneal dialysis use are needed.

RSK promotes G2/M transition through activating phosphorylation of Cdc25A and Cdc25B

Activation of the mitogen-activated protein kinase (MAPK) cascade in mammalian cell lines positively regulates the G2/M transition. The molecular mechanism underlying this biological phenomenon remains poorly understood. Ribosomal S6 kinase (RSK) is a key downstream element of the MAPK cascade. Our previous studies established roles of RSK2 in Cdc25C activation during progesterone-induced meiotic maturation of Xenopus oocytes. In this study we demonstrate that both recombinant RSK and endogenous RSK in Xenopus egg extracts phosphorylate all three isoforms of human Cdc25 at a conserved motif near the catalytic domain. In human HEK293 and PC-3mm2 cell lines, RSK preferentially phosphorylates Cdc25A and Cdc25B in mitotic cells. Phosphorylation of the RSK sites in these Cdc25 isoforms increases their M-phase-inducing activities. Inhibition of RSK-mediated phosphorylation of Cdc25 inhibits G2/M transition. Moreover, RSK is likely to be more active in mitotic cells than in interphase cells, as evidenced by the phosphorylation status of T359/S363 in RSK. Together, these findings indicate that RSK promotes G2/M transition in mammalian cells through activating phosphorylation of Cdc25A and Cdc25B.

Preeclampsia as a risk factor for diabetes: a population-based cohort study

BACKGROUND

Women with preeclampsia (PEC) and gestational hypertension (GH) exhibit insulin resistance during pregnancy, independent of obesity and glucose intolerance. Our aim was to determine whether women with PEC or GH during pregnancy have an increased risk of developing diabetes after pregnancy, and whether the presence of PEC/GH in addition to gestational diabetes (GDM) increases the risk of future (postpartum) diabetes.

METHODS AND FINDINGS

We performed a population-based, retrospective cohort study for 1,010,068 pregnant women who delivered in Ontario, Canada between April 1994 and March 2008. Women were categorized as having PEC alone (n=22,933), GH alone (n=27,605), GDM alone (n=30,852), GDM+PEC (n=1,476), GDM+GH (n=2,100), or none of these conditions (n=925,102). Our main outcome was a new diagnosis of diabetes postpartum in the following years, up until March 2011, based on new records in the Ontario Diabetes Database. The incidence rate of diabetes per 1,000 person-years was 6.47 for women with PEC and 5.26 for GH compared with 2.81 in women with neither of these conditions. In the multivariable analysis, both PEC alone (hazard ratio [HR]=2.08; 95% CI 1.97-2.19) and GH alone (HR=1.95; 95% CI 1.83-2.07) were risk factors for subsequent diabetes. Women with GDM alone were at elevated risk of developing diabetes postpartum (HR=12.77; 95% CI 12.44-13.10); however, the co-presence of PEC or GH in addition to GDM further elevated this risk (HR=15.75; 95% CI 14.52-17.07, and HR=18.49; 95% CI 17.12-19.96, respectively). Data on obesity were not available.

CONCLUSIONS

Women with PEC/GH have a 2-fold increased risk of developing diabetes when followed up to 16.5 years after pregnancy, even in the absence of GDM. The presence of PEC/GH in the setting of GDM also raised the risk of diabetes significantly beyond that seen with GDM alone. A history of PEC/GH during pregnancy should alert clinicians to the need for preventative counseling and more vigilant screening for diabetes. Please see later in the article for the Editors' Summary.

Strongly interacting photons in asymmetric quantum well via resonant tunneling

We propose an asymmetric quantum well structure to realize strong interaction between two slow optical pulses. The essential idea is the combination of the advantages of inverted-Y type scheme and resonant tunneling. We analytically demonstrate that giant cross-Kerr nonlinearity can be achieved with vanishing absorptions. Owing to resonant tunneling, the contributions of the probe and signal cross-Kerr nonlinearities to total nonlinear phase shift vary from destructive to constrictive, leading to nonlinear phase shift on order of π at low light level. In this structure, the scheme is inherent symmetric for the probe and signal pulses. Consequently, the condition of group velocity matching can be fulfilled with appropriate initial electron distribution.

Construction of three different recombinant scorpion fusion proteins with bifunctional activity

This is the first report of three different fusion proteins with an antitumor-analgesic peptide obtained from Chinese scorpion Buthus martensii Karsch (BmKAGAP). The fusion proteins were constructed in the form of chimeric toxins, aiming to obtain bifunctional analgesic and antitumor activity. The fusion proteins consisted of luteinizing hormone-releasing hormone (LHRH), three different types of flexible linkers (L1, Ser-Ser-His-His-His-His-His-His-Ser-Ser-Gly-Leu-Val-Pro-Arg-Gly-Ser-His-Met; L2, Gly-Gly-Gly-Ser-Gly-Gly-Gly-Ser; L3, Ser-Gly-Gly-Ser-Gly-Gly-Ser-Gly-Gly-Gly-Ser-Ser-Gly-Gly-Ser-Gly-Gly-Gly-Gly-Ser-Gly-Gly-Gly-Gly-Ser), and BmKAGAP. The genes coding three fusion proteins were cloned and expressed in E. coli in soluble form. Following two successive column chromatographic separations, purified fusion proteins were obtained. These fusion proteins exhibited analgesic activity in mice and were cytotoxic to a hepatocellular carcinoma cell line Hep3B.

Aerobic power assessment by using a 10 min heart rate control running on treadmill

AIM

This study evaluated the reliability and validity of a proposed 10 min running speed variance test (RSVHRC) in assessing aerobic power at which the intensity was controlled at 80% of age-predicted maximal heart rate (HR).

METHODS

Forty-four college students (21 men and 23 women, age: 21+/-3 years, height: 166.6+/-7.9 cm, weight: 61.7+/-9.3 kg) were recruited to undergo 2 RSVHRC test trials, and a maximal exercise test at least 24 hours apart. The test consisted of a 3-min warm-up at 1.67 km/h, followed by adjusting speed up to either at 2.5 m/s or 2.78 m/s immediately depending upon onset HR after the warm-up. HR was monitored every 30 seconds and running speed was adjusted accordingly to maintain HR (+/-5bpm) for 10 minutes. RSVHRC was determined by the slope of distance/time relationship from 3rd to 10th min.

RESULTS

Pair t-test showed that there was no significant difference between 1st (2.38+/-0.58 m/s) and 2nd trial (2.40+/-0.63 m/s). Intraclass correlation coefficient (ICC) score showed that RSVHRC was highly reliable (ICC=0.98, 95% CI=0.97-0.99). Coefficient of variation, standard error of measurement (SEM), and %SEM were 4.8%, 0.12 m/s, 5.02% respectively. Additionally, a Pearson product-moment correlation coefficient demonstrated 2 trials were correlated with maximal oxygen uptake (46.6+/-8.1 mL/kg/min) at r=0.74, 0.71 (P<0.05).

CONCLUSION

In conclusion, 80%HRmax RSVHRC is an easy and highly reliable submaximal exercise test that provides good validity to assess aerobic power in young and healthy population, which can be applied on treadmill setting.

Inhibitory effect of a novel resveratrol derivative on nitric oxide production in lipopolysaccharide-activated microglia

Excessive nitric oxide (NO) production by activated microglial cells has been implicated in various neurodegenerative diseases. In the present study, we found that a new resveratrol derivative, (E)-5-(3-nitrostyryl)benzene-1,3-diol (RV06), has a more potential inhibitory effect on the production of NO in LPS-activated N9 microglial cells, and the result was confirmed on primary rat microglial cells. Further studies showed that RV06 inhibited LPS-induced iNOS expression in N9 microglial cells, with no activity on direct scavenging nitric oxide radical in a cell-free environment. The results suggest that RV06 might be a potential anti-inflammatory agent or leading compound which can inhibit inflammatory responses of microglia.

In vitro cell culture model for anti-cataract drug penetration studies

Immortalized human corneal epithelial cells (HCECs) and human lens epithelial cells (HLECs) were cultured in vitro. Cells were observed under a phase-contrast microscope and the integrity of cell monolayers was assayed by transepithelial electrical resistance (TEER) determination. The permeability of disulfiram (DSF) through a HCECs monolayer was compared with that of DSF through an excised rabbit cornea. The permeability coefficients of DSF through a HCECs monolayer and excised rabbit cornea were 29.5 +/- 4.8 x 10(-6) cm/s and 34.7 +/- 5.2 x 10(-6) cm/s, respectively. Diethyldithiocarbamate (DDC) had high permeability through HLECs monolayer with a permeability coefficient of 44.6 +/- 7.1 x 10(-6) cm/s. The cytotoxicity of DDC against HLECs was investigated using the trypan blue exclusion test. For a DDC concentration of 5 mmol/l, more than 85% cells were viable. DH3a1 mRNA was expressed in cultured HLECs. The expression of aldehyde dehydrogenase 3a1 (ALDH3a1), which may be be responsible for DSF-DDC conversion, was detected using RT-PCR and agarose gels electrophoresis. These results demonstrate that the permeability of DSF can be detected and intra-ocular drug action may be predicted using the cultured HCEC and HLEC monolayers as model.

Hermes is a localized factor regulating cleavage of vegetal blastomeres in Xenopus laevis

We have identified the RNA-binding protein Hermes in a screen for vegetally localized RNAs in Xenopus oocytes. The RNA localizes to the vegetal cortex through both the message transport organizer (METRO) and late pathways. Hermes mRNA and protein are both detected at the vegetal cortex of the oocyte; however, the protein is degraded within a several hour period during oocyte maturation. Injection of antisense morpholino oligonucleotides (HE-MO) against Hermes caused a precocious reduction in Hermes protein present during maturation and resulted in a phenotype characterized by cleavage defects in vegetal blastomeres. The phenotype can be partially rescued by injecting Hermes mRNA. These results demonstrate that the localized RNA-binding protein Hermes functions during oocyte maturation to regulate the cleavage of specific vegetally derived cell lineages. Hermes most likely performs its function by regulating the translation or processing of one or more target RNAs. This is an important mechanism by which the embryo can generate unique cell lineages. The regulation of region-specific cell division is a novel function for a localized mRNA.

Combinatorial screening for enzyme-mediated coupling. Tyrosinase-catalyzed coupling to create protein--chitosan conjugates

In nature, tyrosinase-generated o-quinones are commonly involved in processes that lead to functional biomaterials. These biomaterials are chemically complex and have been difficult to analyze. Furthermore, the cascade of reactions involving o-quinones is poorly understood, and it has been difficult to mimic ex vivo for materials processing. We report the use of a combinatorial approach to learn how tyrosinase and low molecular weight phenolic precursors can be used to generate biologically active protein-polysaccharide conjugates. Specifically, we screened various phenolic coupling precursors and various reaction conditions for the coupling of proteins onto the polysaccharide chitosan. Several natural phenols were identified as appropriate precursors for the coupling of polyhistidine tagged organophosphorus hydrolase (His-OPH) onto chitosan films. OPH activity was retained upon coupling and subsequent studies indicated that the histidine tag was not necessary for coupling. Using conditions identified for His-OPH coupling, we observed that various biologically active proteins (cytochrome c, OPH, and His-CAT) could be coupled onto chitosan films. The glycosylated protein horseradish peroxidase was not effectively coupled onto chitosan under the conditions studied. In all cases studied, we observed that coupling required a phenolic precursor, suggesting that tyrosinase is unable to couple by reaction with surface tyrosyl residues of the target protein. In conclusion, this study illustrates a combinatorial approach for the "discovery" of conditions to couple biologically active proteins onto chitosan through natural, quinone-based processes.

Sacral parasite conjoined twin

BACKGROUND

A variant of conjoined twins is one in which one twin is incomplete.

CASE

A female infant was born vaginally at 40 weeks' gestation to a healthy primipara. No important abnormalities were noted during prenatal examinations. The infant was fully developed in all external aspects except for a parasitic body conjoined with her sacrococcygeal region. Separated by operation 2 weeks after birth, the parasite contained lower limbs, adipose tissue, muscles, and a bowel sac. Over 4 years of observation, no abnormalities have been found since the operation.

CONCLUSION

Obstetricians should be aware of the existence of a parasite twin during prenatal examinations and of the importance of the differential diagnosis of parasite and teratoma, a neoplasm with malignant potential.

Enhancement of organophosphorus hydrolase yield in Escherichia coli using multiple gene fusions

It was previously shown that organophosphorus hydrolase (OPH) expression and purification could be tracked by fluorescence of green fluorescent protein (GFP) when synthesized as an N-terminal fusion with GFP (Cha et al., 2000; Wu et al., 2000). In order to enhance OPH productivity while utilizing the advantage of the reporter protein (GFP), two copies of OPH were cloned in tandem following the gfp(uv) gene (e.g., GFP-OPH(n=2)). Both anti-GFP and anti-OPH Western blots demonstrated that a higher yield was achieved in comparison to the one copy fusion (GFP-OPH). Importantly, the fusion protein was still fluorescent as determined via microscopy. In contrast, a fusion containing two copies of OPH without GFP, and an operon fusion of two OPHs with two independent ribosomal binding sites, did not result in a higher yield than one OPH expressed alone.

Tumorhead, a Xenopus gene product that inhibits neural differentiation through regulation of proliferation

Tumorhead (TH) is a novel maternal gene product from Xenopus laevis containing several basic domains and a weak coiled-coil. Overexpression of wild-type TH resulted in increased proliferation of neural plate cells, causing expansion of the neural field followed by neural tube and craniofacial abnormalities. Overexpressed TH protein repressed neural differentiation and neural crest markers, but did not inhibit the neural inducers, pan-neural markers or mesodermal markers. Loss of function by injection of anti-TH antibody inhibited cell proliferation. Our data are consistent with a model in which tumorhead functions in regulating differentiation of the neural tissues but not neural induction or determination through its effect on cell proliferation.

DNA microarray-based identification of genes controlled by autoinducer 2-stimulated quorum sensing in Escherichia coli

Bacterial cell-to-cell communication facilitates coordinated expression of specific genes in a growth rate-II and cell density-dependent manner, a process known as quorum sensing. While the discovery of a diffusible Escherichia coli signaling pheromone, termed autoinducer 2 (AI-2), has been made along with several quorum sensing genes, the overall number and coordination of genes controlled by quorum sensing through the AI-2 signal has not been studied systematically. We investigated global changes in mRNA abundance elicited by the AI-2 signaling molecule through the use of a luxS mutant that was unable to synthesize AI-2. Remarkably, 242 genes, comprising ca. 5.6% of the E. coli genome, exhibited significant transcriptional changes (either induction or repression) in response to a 300-fold AI-2 signaling differential, with many of the identified genes displaying high induction levels (more than fivefold). Significant induction of ygeV, a putative sigma(54)-dependent transcriptional activator, and yhbH, a sigma(54) modulating protein, suggests sigma(54) may be involved in E. coli quorum sensing.

Minilaparotomy for internal drainage of a symptomatic lymphocele after renal transplantation

Development of a lymphocele after renal transplantation is a well-described complication that occurs with relative frequency. Management options include simple aspiration with sclerotherapy and operative marsupialization of the lymphoceles into the peritoneal cavity. Laparoscopic internal drainage has been favored in recent reports. Still, the laparoscopic procedure is associated with a number of potential problems, including difficulty in localizing lymphoceles if laparoscopic ultrasound is unavailable. In addition, lobulated lymphoceles are more difficult to completely dissect with laparoscopy, and lymphoceles always occur on the anterior and medial aspects of the graft which are easily approached directly from the anterior skin. We tried to resolve these complications by modifying traditional laparotomy and proved that laparoscopy is a progressive, popular procedure, and that fenestration with finger dissection of the lobulated lymphoceles through minilaparotomy is still a reliable, effective procedure.

Effects of in situ cobalt ion addition on the activity of a gfp-oph fusion protein: the fermentation kinetics

The effects of cobalt ion addition and inducer concentration were studied in the fermentation of E. coli BL21 expressing a GFP (green fluorescent protein)-OPH (organophosphorus hydrolase) fusion protein. It was found that cobalt ion addition improved the OPH activity significantly. When 2 mM of CoCl(2) was supplied during the IPTG-induction phase, OPH activity was enhanced approximately 10-fold compared to the case without cobalt or by the addition of cobalt to the cell extracts. Results indicate, therefore, that incorporation of the cobalt during synthesis is needed for enhanced activity. Also, the maximum OPH activity was not linearly related to inducer concentration. A mathematical model was then constructed to simulate these phenomena. Model parameters were determined by constrained least-squares and optimal IPTG and cobalt addition concentrations were obtained, pinpointing the conditions for the maximum productivity. Finally, the GFP fluorescence intensity was found linear to the OPH activity in each fermentation, demonstrating the function of GFP for monitoring its fusion partner's quantity in the bioreactor.

Pseudoginsenoside-F11 attenuates morphine-induced signalling in Chinese hamster ovary-mu cells

Pseudoginsenoside-F11 (PF11), an ocotillol type saponin isolated from Panax quinquefolium L., has been shown to antagonize the behavioral actions of morphine. Biochemical experiments revealed that PF11 could inhibit diprenorphine (DIP) binding with an IC50 of approximately 6.1 microM and reduced the binding potency of morphine in Chinese hamster ovary (CHO)-mu cells. Furthermore, PF11 significantly attenuated morphine-stimulated [35S]GTPgammaS binding in a dose dependent manner, and strongly decreased the efficacy of morphine to inhibit intracellular cAMP production. In addition, PF11 pretreatment could also significantly inhibit naloxone induced cAMP overshoot in the morphine-pretreated cells. However, PF11 per se had no effect on either [35S]GTPgammaS binding or intracellular cAMP accumulation. These data suggested that PF11 antagonized the morphine stimulated opioid receptor signalling directly at the cellular level.

Distinct roles of CaMKII and PKA in regulation of firing patterns and K(+) currents in Drosophila neurons

The Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) and the cAMP-dependent protein kinase A (PKA) cascades have been implicated in neural mechanisms underlying learning and memory as supported by mutational analyses of the two enzymes in Drosophila. While there is mounting evidence for their roles in synaptic plasticity, less attention has been directed toward their regulation of neuronal membrane excitability and spike information coding. Here we report genetic and pharmacological analyses of the roles of PKA and CaMKII in the firing patterns and underlying K(+) currents in cultured Drosophila central neurons. Genetic perturbation of the catalytic subunit of PKA (DC0) did not alter the action potential duration but disrupted the frequency coding of spike-train responses to constant current injection in a subpopulation of neurons. In contrast, selective inhibition of CaMKII by the expression of an inhibitory peptide in ala transformants prolonged the spike duration but did not affect the spike frequency coding. Enhanced membrane excitability, indicated by spontaneous bursts of spikes, was observed in CaMKII-inhibited but not in PKA-diminished neurons. In wild-type neurons, the spike train firing patterns were highly reproducible under consistent stimulus conditions. However, disruption of either of these kinase pathways led to variable firing patterns in response to identical current stimuli delivered at a low frequency. Such variability in spike duration and frequency coding may impose problems for precision in signal processing in these protein kinase learning mutants. Pharmacological analyses of mutations that affect specific K(+) channel subunits demonstrated distinct effects of PKA and CaMKII in modulation of the kinetics and amplitude of different K(+) currents. The results suggest that PKA modulates Shaker A-type currents, whereas CaMKII modulates Shal-A type currents plus delayed rectifier Shab currents. Thus differential regulation of K(+) channels may influence the signal handling capability of neurons. This study provides support for the notion that, in addition to synaptic mechanisms, modulations in spike activity patterns may represent an important mechanism for learning and memory that should be explored more fully.

Reversal of morphine-induced memory impairment in mice by withdrawal in Morris water maze: possible involvement of cholinergic system

The effects of morphine and morphine withdrawal on memory performance were examined in mice by using Morris water maze task. Morphine-induced memory impairment at the doses of 5 and 10 mg/kg recovered after repeated administration. Oxotremorine, a muscarinic receptor agonist, at the dose of 0.1 mg/kg ip, and physostigmine, a cholinesterase inhibitor, at the dose of 0.1 mg/kg ip, significantly antagonized morphine (10 mg/kg sc)-induced memory impairment in mice. Furthermore, repeated naloxone (0.5 mg/kg ip) attenuated scopolamine (0.2 mg/kg ip)-induced memory impairment. By using escalating doses of morphine for 13 days, morphine-induced memory impairment was continuously maintained. When withdrawal was precipitated by naloxone (5 mg/kg ip), or administration of oxotremorine (0.1 and 0.2 mg/kg ip) or physostigmine (0.05 and 0.1 mg/kg ip), the impairment was completely reversed. These results suggest that morphine-induced memory impairment could be partially due to the inhibition of the central cholinergic activity.

Sh and eag K(+) channel subunit interaction in frog oocytes depends on level and time of expression

Subcellular clustering of ion channels critically affects neuronal function. Coexpression of Eag and Sh channel subunits in Xenopus oocytes leads to accelerated decay of the Sh-like transient K(+) current (Chen, M.-L., T. Hoshi, and C.-F. Wu. 1996. Neuron. 17:535-542). We report that such interaction depends critically on functional expression level (controlled by RNA injection quantities and indicated by current amplitudes) and developmental time after RNA injection. The accelerated decay became apparent 3 days after coinjection and increased thereafter. This was observed in different ionic conditions and at different voltage steps. However, decay was not accelerated at low expression levels, either within 1-2 days after injection or with reduced amounts of RNA. With sequential RNA injection, preformation of either Eag or Sh channels prevented interactions with the other subunit. The carboxyl terminus of Eag was found to be involved in accelerating, and in retarding recovery from, N-type inactivation. The interaction was reduced upon patch excision in macropatch measurements, suggesting involvement of cytosolic factors. We have reproduced the absence of interaction between Eag and Sh reported previously within 2 days after RNA injection and with low levels of current expression (Tang, C.-Y., C. T. Schulteis, R. M. Jiménez, and D. M. Papazian. 1998. Biophys. J. 75:1263-1270). Our findings demonstrate that heterologous expression of channels in Xenopus oocytes is a dynamic process influenced by cell physiology and development. These factors must be considered in interpreting the functional properties of heterologously expressed channels.

A cGMP-dependent protein kinase gene, foraging, modifies habituation-like response decrement of the giant fiber escape circuit in Drosophila

The Drosophila giant fiber jump-and-flight escape response is a model for genetic analysis of both the physiology and the plasticity of a sensorimotor behavioral pathway. We previously established the electrically induced giant fiber response in intact tethered flies as a model for habituation, a form of nonassociative learning. Here, we show that the rate of stimulus-dependent response decrement of this neural pathway in a habituation protocol is correlated with PKG (cGMP-Dependent Protein Kinase) activity and foraging behavior. We assayed response decrement for natural and mutant rover and sitter alleles of the foraging (for) gene that encodes a Drosophila PKG. Rover larvae and adults, which have higher PKG activities, travel significantly farther while foraging than sitters with lower PKG activities. Response decrement was most rapid in genotypes previously shown to have low PKG activities and sitter-like foraging behavior. We also found differences in spontaneous recovery (the reversal of response decrement during a rest from stimulation) and a dishabituation-like phenomenon (the reversal of response decrement evoked by a novel stimulus). This electrophysiological study in an intact animal preparation provides one of the first direct demonstrations that PKG can affect plasticity in a simple learning paradigm. It increases our understanding of the complex interplay of factors that can modulate the sensitivity of the giant fiber escape response, and it defines a new adult-stage phenotype of the foraging locus. Finally, these results show that behaviorally relevant neural plasticity in an identified circuit can be influenced by a single-locus genetic polymorphism existing in a natural population of Drosophila.

A novel leg-shaking Drosophila mutant defective in a voltage-gated K(+)current and hypersensitive to reactive oxygen species

1,1'-Dimethyl-4,4'-bipyridinium dichloride (methyl viologen; paraquat), an herbicide that causes depletion of NADPH and generates excessive reactive oxygen species (ROS) in vivo, has been used to screen for ROS-sensitive Drosophila mutants. One mutant so isolated, named quiver(1) (qvr(1)), has a leg-shaking phenotype. Mutants of the Shaker (Sh), Hyperkinetic (Hk), and ether a go-go (eag) genes, which encode different K(+) channel subunits that regulate the A-type K(+) current (I(A)) in different ways, exhibit leg shaking under ether anesthesia and have heightened metabolic rates and shortened life spans. We found that Sh, Hk, and eag mutant flies were all hypersensitive to paraquat. Double-mutant combinations among the three channel mutations and qvr(1) had drastically enhanced sensitivity to paraquat. Synaptic transmission at the larval neuromuscular junction was increased in the qvr(1) mutant to the level of Sh mutants. Similar to eag Sh double mutants, double mutants of eag and qvr(1) showed striking enhancement in synaptic transmission and a wings-down phenotype, the hallmarks of extreme hyperexcitability. Voltage-clamp experiments demonstrated that the qvr(1) mutation specifically disrupted the Sh-dependent I(A) current without altering the other currents [I(K), Ca(2+)-activated fast (I(CF)) and slow (I(CS)) currents, and I(Ca)] in larval muscles. Several deficiency strains of the qvr locus failed to complement qvr(1) and confirmed that ether-induced leg shaking, reduced I(A) current, and paraquat hypersensitivity map to the same locus. Our results suggest that the qvr gene may encode a novel K(+) channel-related polypeptide and indicate a strong link between a voltage-activated K(+) current and vulnerability to ROS.

A green fluorescent protein fusion strategy for monitoring the expression, cellular location, and separation of biologically active organophosphorus hydrolase

Organophosphorus hydrolase (OPH) is capable of degrading a variety of pesticides and nerve agents. We have developed a versatile monitoring technique for detecting the amount of OPH during the expression and purification steps. This involves fusion of the gene for green fluorescent protein (GFP) to the 5' end of the OPH gene and subsequent expression in Escherichia coli. The synthesized fusion protein was directly visualized due to the optical properties of GFP. Western blot analyses showed that the correct fusion protein was expressed after IPTG-induction. Also, the in vivo GFP fluorescence intensity was proportional to the OPH enzyme activity. Moreover, the OPH, which forms a dimer in its active state, retained activity while fused to GFP. Enterokinase digestion experiments showed that OPH was separated from the GFP reporter after purification via immobilized metal affinity chromatography, which in turn was monitored by fluorescence. The strategy of linking GFP to OPH has enormous potential for improving enzyme production efficiency, as well as enhancing field use, as it can be monitored at low concentrations with inexpensive instrumentation based on detecting green fluorescence.