The day-night differences in cognitive and anxiety-like behaviors of mice after chronic sleep restriction

Animal behavioral tests are often conducted during the day. However, rodents are nocturnal animals and are primarily active at night. The aim of this study was to determine whether there are diurnal changes in cognitive and anxiety-like performance of mice following chronic sleep restriction (SR). We also investigated whether this phenotypic difference is related to the diurnal variation of glymphatic clearance of metabolic wastes. Mice received 9-day SR by the use of the modified rotating rod method, followed by the open field, elevated plus maze, and Y-maze tests conducted during the day and at night, respectively. Brain β-amyloid (Aβ) and tau protein levels, the polarity of aquaporin4 (AQP4), a functional marker of the glymphatic system, and glymphatic transport ability were also analyzed. SR mice exhibited cognitive impairment and anxiety-like behaviors during the day, but not at night. AQP4 polarity and glymphatic transport ability were higher during the day, with lower Aβ_1-42 , Aβ_1-40 , and P-Tau levels in the frontal cortex. These day-night differences were totally disrupted after SR. These results reveal the diurnal changes in behavioral performance after chronic SR, which may be related to circadian control of AQP4-mediated glymphatic clearance of toxic macromolecules from the brain.

[Status of fungal sepsis among preterm infants in 25 neonatal intensive care units of tertiary hospitals in China]

Objective: To analyze the prevalence and the risk factors of fungal sepsis in 25 neonatal intensive care units (NICU) among preterm infants in China, and to provide a basis for preventive strategies of fungal sepsis. Methods: This was a second-analysis of the data from the "reduction of infection in neonatal intensive care units using the evidence-based practice for improving quality" study. The current status of fungal sepsis of the 24 731 preterm infants with the gestational age of <34⁺⁰ weeks, who were admitted to 25 participating NICU within 7 days of birth between May 2015 and April 2018 were retrospectively analyzed. These preterm infants were divided into the fungal sepsis group and the without fungal sepsis group according to whether they developed fungal sepsis to analyze the incidences and the microbiology of fungal sepsis. Chi-square test was used to compare the incidences of fungal sepsis in preterm infants with different gestational ages and birth weights and in different NICU. Multivariate Logistic regression analysis was used to study the outcomes of preterm infants with fungal sepsis, which were further compared with those of preterm infants without fungal sepsis. The 144 preterm infants in the fungal sepsis group were matched with 288 preterm infants in the non-fungal sepsis group by propensity score-matched method. Univariate and multivariate Logistic regression analysis were used to analyze the risk factors of fungal sepsis. Results: In all, 166 (0.7%) of the 24 731 preterm infants developed fungal sepsis, with the gestational age of (29.7±2.0) weeks and the birth weight of (1 300±293) g. The incidence of fungal sepsis increased with decreasing gestational age and birth weight (both P<0.001). The preterm infants with gestational age of <32 weeks accounted for 87.3% (145/166). The incidence of fungal sepsis was 1.0% (117/11 438) in very preterm infants and 2.0% (28/1 401) in extremely preterm infants, and was 1.3% (103/8 060) in very low birth weight infants and 1.7% (21/1 211) in extremely low birth weight infants, respectively. There was no fungal sepsis in 3 NICU, and the incidences in the other 22 NICU ranged from 0.7% (10/1 397) to 2.9% (21/724), with significant statistical difference (P<0.001). The pathogens were mainly Candida (150/166, 90.4%), including 59 cases of Candida albicans and 91 cases of non-Candida albicans, of which Candida parapsilosis was the most common (41 cases). Fungal sepsis was independently associated with increased risk of moderate to severe bronchopulmonary dysplasia (BPD) (adjusted OR 1.52, 95%CI 1.04-2.22, P=0.030) and severe retinopathy of prematurity (ROP) (adjusted OR 2.55, 95%CI 1.12-5.80, P=0.025). Previous broad spectrum antibiotics exposure (adjusted OR=2.50, 95%CI 1.50-4.17, P<0.001), prolonged use of central line (adjusted OR=1.05, 95%CI 1.03-1.08, P<0.001) and previous total parenteral nutrition (TPN) duration (adjusted OR=1.04, 95%CI 1.02-1.06, P<0.001) were all independently associated with increasing risk of fungal sepsis. Conclusions: Candida albicans and Candida parapsilosis are the main pathogens of fungal sepsis among preterm infants in Chinese NICU. Preterm infants with fungal sepsis are at increased risk of moderate to severe BPD and severe ROP. Previous broad spectrum antibiotics exposure, prolonged use of central line and prolonged duration of TPN will increase the risk of fungal sepsis. Ongoing initiatives are needed to reduce fungal sepsis based on these risk factors.

[Clinical characteristics and risk factors of periventricular-intraventricular hemorrhage in extremely low birth weight infants]

Objective: To analyze the clinical characteristics and risk factors of periventricular-intraventricular hemorrhage (PIVH) in extremely low birth weight infants (ELBWI). Methods: From January 2019 to January 2022, the clinical data of 238 ELBWI admitted to the intensive care unit of Henan Provincial Children's Hospital within 1 week after birth and regular head color ultrasound examination were retrospective reviewed. The infants were divided into PIVH group and non-PIVH group according to whether PIVH occurred. The incidence and time of PIVH were described, and the differences in basic clinical features, perinatal conditions, postnatal treatment and complications between the two groups were compared. The risk factors of PIVH in ELBWI were further explored by multivariate binary logistic regression analysis. Results: Among 238 ELBWI (146 males and 92 females), 82 cases (34.5%) developed PIVH, including 28 cases (11.8%) of severe PIVH and 54 cases (22.7%) of mild PIVH. Among the 82 cases of PIVH, 68 cases occurred within 3 days after birth. Gestational age [(27.4±1.5) weeks vs (27.8±1.5) weeks, P=0.012], gestational diabetes mellitus [0 vs 9.0%(14/156), P=0.005], fibrinogen (FIB) [(1.8±0.5) g/L vs (2.7±0.9) g/L, P=0.012] were lower in PIVH group than in non-PIVH group. However, intrauterine distress [46.3%(38/82) vs 11.5%(18/156), P<0.001], birth asphyxia [85.4%(70/82) vs 62.8%(98/156), P<0.001], patent ductus arteriosus (PDA) [65.9%(54/82) vs 51.3%(80/156）, P=0.017], failure to withdraw invasive ventilator within 1 week [82.9%(14/82) vs 67.3%(105/156), P=0.010], use of vasoactive drugs within 1 week [28.0%(23/82) vs 15.4%(24/156), P=0.020], acidosis [28.0%(23/82) vs 12.2%(19/156), P=0.002], and hemorrhagic disease [18.3%(15/82) vs 7.1%(11/156), P=0.008] were higher in PIVH group than in non-PIVH group. Multivariate binary logistic regression analysis found that the risk factors for PIVH in ELBWI were acidosis (OR=2.257, 95%CI: 1.104-4.614, P=0.026), use of vasoactive drugs within 1 week (OR=2.274, 95%CI: 1.148-4.504, P=0.018), bleeding disorders (OR=2.583, 95%CI: 1.075-6.206, P=0.034) use of vasoactive drugs within 1 week (OR=2.301, 95%CI: 1.153-4.591, P<0.001). Conclusions: The incidence of PIVH in ELBWI is high, which mostly occurs within 3 days after birth. Acidosis, hemorrhagic disease, use of vasoactive agents within 1 week and failure to evacuate invasive ventilators within 1 week may increase the risk of PIVH in ELBWI.

Optimal reference genes for real-time quantitative PCR and the expression of sigma factors in Acidithiobacillus caldus under various conditions

AIMS

Acidithiobacillus caldus is an important sulphur-oxidizing bacterium that plays crucial roles in the bioleaching industry. This study aims to analyse the optimal reference gene for real-time quantitative PCR (RT-qPCR) under different conditions and investigate the transcription levels of the sigma factor genes in the stress response.

METHODS AND RESULTS

We selected six housekeeping genes and analysed them via RT-qPCR using two energy resources, under four stress conditions. Three statistical approaches BestKeeper, geNorm, and NormFinder were utilized to determine transcription stability of these reference genes. The gapdH gene was the best internal control gene using elemental sulphur as an energy resource and under heat stress, map was the best internal control gene under pH and osmotic stress, era was the best internal control gene for the K₂ S₄ O₆ energy resource, and rpoC was the best internal control gene under Cu²⁺ stress. Furthermore, the expressional levels of 11 sigma factors were analysed by RT-qPCR in the stress response.

CONCLUSIONS

Stable internal control genes for RT-qPCR analysis of A. caldus were determined, and the expression patterns of sigma factor genes of A. caldus were investigated.

SIGNIFICANCE AND IMPACT OF THE STUDY

The identification of the optimal reference gene and analysis of transcription levels of sigma factors in A. caldus can provide clues for reference gene selection and the study of sigma factor function.

Development and preliminary application of novel genomewide SSR markers for genetic diversity analysis of an economically important bio-control agent Platygaster robiniae (Hymenoptera: Platygastridae)

Platygaster robiniae Buhl and Duso (Hymenoptera: Platygastridae) is an egg-larvae parasitoid of the black locust gall midge (Obolodiplosis robiniae) (Haldeman) (Diptera: Cecidomyiidae) which is a serious invasive pest in China, where it attacks an important hardwood species, the black locust tree, Robini pseudoacacia L. (Fabales: Fabaceae). Despite the use of P. robiniae as an effective biocontrol agent, the absence of sequence data and other molecular markers have limited its genetic applications for pest management in forests. Simple-sequence repeats (SSRs) are valuable molecular markers for population genetic structure studies. In the present study, we identified 14,123 SSRs, of which 7799 SSR primer pairs were successfully designed. Subsequently, 240 SSR were chosen and tested with 48 P. robiniae accessions from two geographically separated populations in north and south China. Of these, 34 were polymorphic, with an average of three alleles (N_a) and four genotypes (N_G) each. The average values of observed heterozygosity (H_o) was 0.3514, expected heterozygosity (H_e) 0.4167, Shannon's information index (I) 0.7143, and polymorphism information content (PIC) 0.3558, respectively. Neighbour joining analysis (bootstrap 1000) revealed that Chengdu (CD) and Dangdong (DD) popluations clustered into two main divisions, and some individuals from two popluations clustered together as the third devision, which indicated the gene flow and genetic differentiation were present between two populations. Our finding indicates that these SSR markers will be useful for further studies on the genotype identification and genetic mapping of the genus Platygaster.

[Development of a quantitative serum assay of Golgi protein 73 in hepatocellular carcinoma using xMAP technology]

Objective: To establish a quantitative assay of serum Golgi protein 73 (GP73) using xMAP technology and evaluate its performance. Methods: Monoclonal antibodies against GP73 were prepared and purified, and antibody pair screening was performed by double-antibody sandwich enzyme-linked immunosorbent assay. The screened antibodies were used to construct a Luminex liquid chip detection system, and the analysis performance of the detection system was evaluated. The serum levels of GP73 were detected in 90 clinical samples from healthy controls and patients with chronic hepatitis B infection (CHB) and hepatocellular carcinoma (HCC). Results: Five anti-GP73 monoclonal antibodies were prepared and purified, and 5 antibody pairs were successfully screened. The Luminex liquid chip detection system of GP73 was successfully constructed using 8F10D1 and 10B9F11 antibody pairs. The analytical performance evaluation showed that the sensitivity of this system was 0.25 ng/ml and the dynamic range was 0.25-100 ng/ml. No cross reactivity was observed. The intra- and inter-assay variation for GP73 was <8% and <11%, respectively. The recovery was 83%-92%. The linear regression equation was y=1.141x+ 6.436 (r(2)=0.998 4, P<0.001). The GP73 concentrations in the serum samples of healthy control, CHB group, and HCC group were 42.8 (38.68, 55.90) ng/ml, 61.49 (43.59, 81) ng/ml, and 122.78 (49.36 liter, 264.55) ng/ml, respectively. The levels of GP73 in HCC group were significantly higher than those in CHB group and healthy controls (P<0.05). Moreover, the levels of GP73 in CHB group were significantly higher than those in healthy controls (P<0.05). Conclusions: A liquid chip detection system of GP73 was successfully constructed. It provides a powerful tool for the clinical application of GP73 in the future.

[Effect of clinical characteristics on relapse of alcohol dependence: a prospective cohort study]

OBJECTIVE

To investigate whether craving and demographic factors to predict relapse in alcohol dependence.

METHODS

This study was a prospective cohort study. From August 2017 to August 2018, 158 Han male inpatients who met the diagnositic and statistical manual disorders-fourth version(DSM-IV) alcohol dependence diagnostic criteria were recruited from three mental hospitals in China. The participants were interviewed at baseline and followed up by telephone after 3 months for assessment. The baseline assessment after the acute withdrawal period included demographic data and alcohol-related data, clinical institute withdrawal assessment-advanced revised (CIWA-Ar), withdrawal and cue-induced craving on visual analog scale (VAS), Michigan alcoholism screening test (MAST), self-rating anxiety scale (SAS), self-rating depression scale (SDS) and alcohol urge questionnaire (AUQ). According to the follow-up results, "relapse" was defined as the consumption of beverages containing ethanol at any time during the follow-up study, and "time to relapse" was defined as the number of days from the first drinking to the baseline. Whether relapse occurred and the time to relapse were the primary endpoints. Cox proportional hazard regression model was used to analyze the factors affecting the relapse of alcohol dependence.

RESULTS

In the study, 158 alcohol dependence patients were finally included, age from 21 to 60 years, with the mean age of (40.31±9.14) years. The relapse rate was 63.7% three months after baseline assessment. According to Cox univariate analysis and multivariate analysis, the age (OR=0.975, P=0.030) and CIWA-Ar scores (OR=1.126, P=0.010) significantly predicted relapse. And there was no significant difference in education level, marital status, withdrawal and cue-induced craving on VAS, SAS and SDS between the relapse group and the non-relapse group (P>0.05).

CONCLUSION

Age and severity of alcohol-dependent withdrawal symptoms during hospitalization are significantly related to relapse for alcohol in alcohol-dependent patients. To be exact, the older age is a protective factor, that is to say, the younger patients are prone to relapse, while the risk of relapse is raised by the higher severity of withdrawal symptoms. However, neither cue-induced nor withdrawal craving can predict relapse of alcohol-dependent patients.

[Three-dimensional finite element analysis of four-implants supported mandibular overdentures using two different attachments]

Objective: To compare the biomechanical characteristics of four-implants mandibular overdentures supported by Locator attachment or bar-clip attachment under different mechanical loads using three-dimensional finite element analysis method. Methods: Two different models of four-implants supported mandibular overdentures using Locator attachment and bar-clip attachment (hereinafter called Locator model and bar-clip model) were established. Each model was subjected to five different mechanical loading conditions: 100 N vertical loading in central incisor (vertical load of incisor), 100 N vertical loading or oblique loading in canine (vertical or oblique loads of canines), 100 N vertical or oblique loading in mandibular first molar (vertical or oblique loads of mandibular first molar). The stress distributions in implants, peri-implant bone and mucosa were recorded under the above five conditions to evaluate the effects of different attachments on the biomechanical properties of implant-supported mandibular overdentures. Results: Regardless of loading conditions and types of attachments, the stress concentration in implants were located at the neck of implants, and the stress concentration in peri-implant bone was located in the cortical bone. The stress values in mucosa were always much smaller than those in implants and cortical bone. Regardless of loading positions (on canine or on mandibular first molar), the maximum stress at the bone interface around the implant under lateral loading was much higher than that under vertical loading. Under various loading conditions, the stress in implants and cortical bone of the Locator model (the highest von Mise stress value was respectively 79.5 and 22.3 MPa) were lower than that of bar-clip model (the highest von Mise stress value was 110.3 and 28.7 MPa respectively) while the maximum compressive stress in mucosa (0.198 MPa) in Locator model was slightly higher than that in the bar-clip model (0.137 MPa). Conclusions: In clinical practice, the lateral force applied to the implant-retained overdenture should be minimized to avoid complications caused by pathological loads. Under the same loading condition, the stress distributions in overdenture using Locator attachment are more dispersed, which is more conducive to long-term stability of implants.

Linear growth model analysis of factors affecting boar semen characteristics in Southern China

This study investigated the factors affecting the semen traits of boars in Southern China. A total of 172,408 ejaculates of boars from 9 AI centers were collected from January 2013 to May 2016. A linear growth model was used to analyze the effects of leve1 1 (boar breed, age, season, and boar age at herd entry) and level 2 (housing type) factors on semen quality. The intraclass correlation coefficients of semen volume, total sperm number, functional sperm number, sperm concentration, motility, and abnormal sperm were 0.62, 0.62, 0.61, 0.60, 0.54, and 0.70, respectively. Boars reared in ordinary houses had lower total and functional sperm numbers than those reared in air filtration houses ( < 0.05). The functional sperm number of Duroc boars was lower than that of Landrace and Yorkshire boars ( < 0.05). The total and functional sperm numbers were lowest from May to September and peaked at the age of 34.1 and 37.7 mo, respectively. Furthermore, boars aged 8 and 9 mo at herd entry had greater functional sperm numbers than those aged 5, 6, 7, and 12 mo at herd entry ( < 0.05), whereas no significant difference was observed between boars aged 8 mo and boars aged 9 mo at herd entry ( > 0.05). In conclusion, the linear growth model is suitable for longitudinal data analysis. To improve boar breeding, sunstroke prevention in the early spring should be given greater attention. Importantly, 8 mo appears to be the most suitable age for boar introduction, especially for Duroc boars.

[Verification of skin paste electrodes used in wireless polysomnography]

OBJECTIVE

To explore an electrode suitable for wireless portable sleep monitoring equipment and analyze the result of the signals of electrooculogram (EOG) and electroencephalography (EEG) collected by this kind of flexible electrodes.

METHODS

The flexible electrodes were prepared by microelectromechanical systems (MEMS) technology. This kind of electrodes consisted parylene, chromium, and gold. Parylene, the flexible substrate of this kind of flexible electrodes, was of biocompatibility. Between parylene and gold there was an adhesion layer of chromium, which connected parylene and gold tightly. Then the flexible electrodes were stuck to medical adhesive tape. The electrodes were designed and made into a grid to make sure that the medical adhesive tape could tape on the skin tightly, so that the contact impedance between the electrodes and the skin would be reduced. Then the alternating current impedance of the electrode were tested by the CHI660E electrochemical workstation after the electrode was achieved. To make sure that this kind of electrodes could be used in EOG monitoring, the electrodes were connected to a wireless signal acquisition suite containing special biological signal acquisition and digital processing chip to gather different sites around the eyes and the electrical signals of different directions of the eye movements, then analyzed the signal-to-noise ratio of the EOG. At the end, the Philips A6 polysomnography was used to compare the noise amplitude of the EEG signals collected by the flexible electrode and the gold cup electrode.

RESULTS

The electrodes stuck to the skin tightly, and these electrodes could collect signals that we wanted while the experiment was performed. The alternating current impedance of the flexible electrode was between 4 kΩ and 13 kΩ while with the frequency of alternating current under 100 Hz, most EEG signal frequencies were at this range. The EOG signals collected by the flexible electrodes were in line with the clinical requirements. The noise amplitude of EEG signals collected by the flexible electrodes was lower than that of the electrical signals collected by the gold cup electrodes.

CONCLUSION

The flexible electrode could be taken into consideration as an alternative electrode for monitoring EOG and EEG signals, and the wireless portable sleep monitoring devices are to be further developed in the future.

[Fibroblast growth factor receptor 1 propagates estrogen and fluid shear stress driven proliferation and differentiation response in MC3T3-E1 cells]

Fluid shear stress (FSS) and estrogen exposure positively regulate bone metabolism. Fibroblast growth factor receptor 1 (FGFR1) plays a vital role in FSS-induced osteogenesis. An in vitro experiment with MC3T3-E1 cells combined with microarray analysis aided us in identification of the genes differentially expressed in response to FSS and highlighted the role of FGFR1 in this process. Both estrogen exposure and FSS increase methyl thiazol tetrazolium (MTT) values and alkaline phosphatase (ALP) activity, as well as the levels of Runt-related transcription factor 2 (Runx2) and osteocalcin (OCN). The effects of estrogen exposure and FSS were cumulative. Treatment with PD166866 inhibitor of the FGFR1 reduced the MTT values, increased ALP activity, and increased the levels of Runx2 and OCN. To investigate the regulation of FGFR1 signaling in stressed cells, a number of key components of the mitogen-activated protein kinase (MAPK) cascade were quantitatively examined. Neither estrogen nor FSS change the protein expression of extracellular signal-regulated kinase (ERK), Jun amino-terminal kinases (JNK) or p38, but positively influence their phosphorylation levels. Treatment with the FGFR1 inhibitor induced an increase in ERK phosphorylation levels only. In summary, estrogen exposure and FSS have a synergistic effect in osteogenesis. FGFR1 promotes osteoblast proliferation and inhibits the differentiation of osteoblasts. In MC3T3-E1 cells, FGFR1 signaling responds to independent and combined effects of estrogen and FSS. MAPK cascades participate in osteogenesis, but only the ERK signaling pathway responds to FGFR1.

[Trend of caesarean section rate and puerpera characteristics: based on Robson classification]

Objective: To analyze the trend in caesarean section rate and puerpera characteristics in hospital, and provide valuable information for maternal and child health policy making and clinical practice. Methods: A total of 12 041 women who delivered in the affiliated Chaohu Hospital of Anhui Medical University from October 1, 2010 to September 30, 2016 were selected. Based on Robson classification system, changes in the rate of caesarean delivery as well as its relationship with two-child policy and infant sex ratio were analyzed. Results: The overall caesarean section rate gradually decreased from 66.9% to 44.2% during the past six years. Respectively, the caesarean section rate in primiparae with singleton term babies decreased to 32.1% and the rate in multiparas without uterine scar decreased to 14.2%, and the rate in premature delivery decreased to 22.9%, the differences were significant (P<0.01). The proportion of vaginal delivery (R1, R3), multiparas with uterine scar (R5) and twins pregnancy (R8) increased. the differences were significant (P<0.01). The annual overall newly-born sex ratio ranged from 110∶100 to 128∶100. In group R1, more babies were girls, the proportion was stable, more women with premature delivery and multiparas had boy babies, but the boy babies by multiparas without uterine scar obviously decreased in the last 2 years. Conclusions: Primiparae with singleton head birth, multipara without uterine scar and women with premature deliveries are the key population in the effort of reduction of caesarean section rate. The caesarean section rate and proportion were unstable in multiparas with uterine scar, breech deliveries and twin deliveries. The application of Robson classification system can improve the comparability of the surveillance data.

Effects of feeding regimen on weight gain, semen characteristics, libido, and lameness in 170- to 250-kilogram Duroc boars

A 2-period field trial was conducted to determine the effects of feeding regimen on weight gain, semen characteristics, libido, and lameness in 170- to 200-kg (period 1) and 200- to 250-kg (period 2) boars. Sixty-one Duroc boars were allotted to 1 of 3 dietary treatments and 15 g/d fish oil was also provided for each experimental boar, to maintain the n-6:n-3 intake ratio at approximately 6.1:1. The energy intakes of the 3 treatment groups were controlled by basing the feed intake on a corn-soybean meal-based diet (3.11 Mcal/kg of ME) to create: 1) low energy intake group (L, = 20, 7.3 Mcal/d of ME), 2) medium energy intake group (M, = 20, 7.7 Mcal/d of ME), and 3) high energy intake group (H, = 21, 8.3 Mcal/d of ME) in period 1. Feed intake was then increased to 7.6, 8.2, and 8.6 Mcal/d of ME for the 3 groups, respectively, in period 2. During the 28-wk experimental period, boar weight gain, testis volume, semen characteristics, libido, toe measurements, claw lesions, and lameness were examined, and the number of boars culled in each group was recorded to calculate the culling rate. Although there were no differences in testis volume, sperm concentration, and motility, the percentage of abnormal sperm, the percentage of claw lesions, and claw lesion scores differed among treatments ( > 0.05), and ADG was significantly increased with the increase of energy intake between the 2 periods ( < 0.05). The M and H boars had significantly greater total sperm number and functional sperm number than the L boars ( < 0.05), while no significant difference was observed between the M and H groups ( > 0.05). Nonetheless, the H boars took more time to mount the collection dummy and produce an ejaculate and, in particular, showed a greater percentage of lameness than the L and M boars ( < 0.05). Therefore, the medium energy intake regimen (energy intakes of 7.7 and 8.2 Mcal/d of ME with ADG of 454.5 and 375.3 g/d in 2 periods, respectively) improved the total sperm number and functional sperm number, and meanwhile decreased the occurrence of lameness in 170- to 250-kg Duroc boars.

Epigenomics alternations and dynamic transcriptional changes in responses to 5-fluorouracil stimulation reveal mechanisms of acquired drug resistance of colorectal cancer cells

A drug-induced resistant cancer cell is different from its parent cell in transcriptional response to drug treatment. The distinct transcriptional response pattern of a drug-induced resistant cancer cell to drug treatment might be introduced by acquired DNA methylation aberration in the cell exposing to sustained drug stimulation. In this study, we performed both transcriptional and DNA methylation profiles of the HCT-8 wild-type cells (HCT-8/WT) for human colorectal cancer (CRC) and the 5-fluorouracil (5-FU)-induced resistant cells (HCT-8/5-FU) after treatment with 5-FU for 0, 24 and 48 h. Integrated analysis of transcriptional and DNA methylation profiles showed that genes with promoter hypermethylation and concordant expression silencing in the HCT-8/5-FU cells are mainly involved in pathways of pyrimidine metabolism and drug metabolism-cytochrome P450. Transcriptional analysis confirmed that genes with transcriptional differences between a drug-induced resistant cell and its parent cell after drug treatment for a certain time, rather than their primary transcriptional differences, are more likely to be involved in drug resistance. Specifically, transcriptional differences between the drug-induced resistant cells and parental cells after drug treatment for 24 h were significantly consistent with the differentially expressed genes (termed as CRG_5-FU) between the tissues of nonresponders and responders of CRCs to 5-FU-based therapy and the consistence increased after drug treatment for 48 h (binomial test, P-value=1.88E−06). This study reveals a major epigenetic mechanism inducing the HCT-8/WT cells to acquire resistance to 5-FU and suggests an appropriate time interval (24–48 h) of 5-FU exposure for identifying clinically relevant drug resistance signatures from drug-induced resistant cell models.

Increased Th17 cells contribute to disease progression in patients with HBV-associated liver cirrhosis

T helper (Th) 17 cells have been demonstrated to participate in the pathogenesis of HBV-associated liver damage. However, little is known regarding the immunopathogenic role of liver fibrosis in patients with HBV-associated liver cirrhosis. The aims of this study were to evaluate whether Th17 cells are related to disease progression in patients and to explore the possible mechanisms. The frequencies of circulating Th17 cells were analysed in 78 patients with hepatitis B and cirrhosis (Child A: 34; Child B: 22; Child C 22) and matched controls. Liver samples were collected from 13 patients with HBV-associated cirrhosis, 23 patients with chronic hepatitis B and 12 healthy controls for immunohistochemical analysis. IL-17 receptor expression was studied on liver biopsies and in human hepatic stellate cells as well as their response to recombinant IL-17 by flow cytometry. Patients with hepatitis B-associated cirrhosis with more severe disease displayed significant increases in peripheral numbers of Th17 cells as well as in IL-17 plasma levels. The increased intrahepatic IL-17(+) cells correlated positively with fibrotic staging scores and clinical progression from CHB to cirrhosis. Moreover, many IL-17(+) cells were located in fibrotic areas in the liver of patients with cirrhosis. In vitro, IL-17 together with IL-17-activated monocytes, could promote the activation of stellate cells, which, in turn, aggravated liver fibrosis and the inflammatory response. In summary, increased peripheral and intrahepatic Th17 cells are enriched in patients with hepatitis B and cirrhosis and contribute further to the severity of disease progression through induction of stellate cell activation.

Natural ventilation for reducing airborne infection in hospitals

High ventilation rate is shown to be effective for reducing cross-infection risk of airborne diseases in hospitals and isolation rooms. Natural ventilation can deliver much higher ventilation rate than mechanical ventilation in an energy-efficient manner. This paper reports a field measurement of naturally ventilated hospital wards in Hong Kong and presents a possibility of using natural ventilation for infection control in hospital wards. Our measurements showed that natural ventilation could achieve high ventilation rates especially when both the windows and the doors were open in a ward. The highest ventilation rate recorded in our study was 69.0 ACH. The airflow pattern and the airflow direction were found to be unstable in some measurements with large openings. Mechanical fans were installed in a ward window to create a negative pressure difference. Measurements showed that the negative pressure difference was negligible with large openings but the overall airflow was controlled in the expected direction. When all the openings were closed and the exhaust fans were turned on, a reasonable negative pressure was created although the air temperature was uncontrolled. The high ventilation rate provided by natural ventilation can reduce cross-infection of airborne diseases, and thus it is recommended for consideration of use in appropriate hospital wards for infection control. Our results also demonstrated a possibility of converting an existing ward using natural ventilation to a temporary isolation room through installing mechanical exhaust fans.

Identification of messenger RNA substrates for mouse T-STAR

Using the method of isolation of specific nucleic acids associated with proteins (SNAAP), we have identified 10 candidate target mRNA substrates bound by mT-STAR (mouse T-STAR protein) from testis extract. Among them, our study focused on Fabp9, a gene that is essential for male gametogenesis, and showed that mT-STAR could directly bind to Fabp9 mRNAs. The binding sites are in a short sequence of the coding region and 3' untranslated region of Fabp9 mRNA. These suggest that mT-STAR can regulate the metabolism and expression of Fabp9. In conclusion, identification of mT-STAR-bound mRNA substrates might help to illustrate the potential spectrum of the process and provide valuable insight into the biological function of this RNA-binding protein in spermatogenesis.

Adaptive watershed segmentation of binary particle image

Oversegmentation is a tough problem in the morphological watershed segmentation of irregular-shaped binary particles, which is usually caused by spurious minima in the inverse distance transform. The position relationship between two objects is clear, according to the value of overlap parameter defined in the paper, and an adaptive algorithm is presented to depress oversegmentation by building the criterion to merge the spurious local minima. Some particle images are provided to validate the performance of the proposed method.

Regulation of apoptosis by phosphatidylinositol 4,5-bisphosphate inhibition of caspases, and caspase inactivation of phosphatidylinositol phosphate 5-kinases

Phosphoinositides such as phosphatidylinositol 3,4,5-trisphosphate and phosphatidylinositol 3,4-bisphosphate promote cell survival and protect against apoptosis by activating Akt/PKB, which phosphorylates components of the apoptotic machinery. We now report that another phosphoinositide, phosphatidylinositol 4,5-bisphosphate (PIP2) is a direct inhibitor of initiator caspases 8 and 9, and their common effector caspase 3. PIP2 inhibited procaspase 9 processing in cell extracts and in a reconstituted procaspase 9/Apaf1 apoptosome system. It inhibited purified caspase 3 and 8 activity, at physiologically attainable PIP2 levels in mixed lipid vesicles. Caspase 3 binding to PIP2 was confirmed by cosedimentation with mixed lipid vesicles. Overexpression of phosphatidylinositol phosphate 5-kinase alpha (PIP5KIalpha), which synthesizes PIP2, suppressed apoptosis, whereas a kinase-deficient mutant did not. Protection by the wild-type PIP5KIalpha was accompanied by decreases in the generation of activated caspases and of caspase 3-cleaved PARP. Protection was not mediated through PIP3 or Akt activation. An anti-apoptotic role for PIP(2) is further substantiated by our finding that PIP5KIalpha was cleaved by caspase 3 during apoptosis, and cleavage inactivated PIP5KIalpha in vitro. Mutation of the P(4) position (D279A) of the PIP5KIalpha caspase 3 cleavage consensus prevented cleavage in vitro, and during apoptosis in vivo. Significantly, the caspase 3-resistant PIP5KIalpha mutant was more effective in suppressing apoptosis than the wild-type kinase. These results show that PIP2 is a direct regulator of apical and effector caspases in the death receptor and mitochondrial pathways, and that PIP5KIalpha inactivation contributes to the progression of apoptosis. This novel feedforward amplification mechanism for maintaining the balance between life and death of a cell works through phosphoinositide regulation of caspases and caspase regulation of phosphoinositide synthesis.

beta-Thymosins are not simple actin monomer buffering proteins. Insights from overexpression studies

beta-Thymosins are the currently favored candidates for maintaining the large actin monomer (G-actin) pool in living cells. To determine if beta-thymosin behaves like a simple G-actin buffering agent in the complex environment of a cell, we overexpressed thymosin beta10 (Tbeta 10) in NIH3T3 cells and determined the effect on the monomer/polymer equilibrium. Tbeta 10 is the predominant beta-thymosin isoform in the NIH3T3 cell line, and it is present in approximately equal molar ratio to profilin and cofilin/actin depolymerizing factor, two other well characterized actin monomer binding proteins. Clonal cell lines that overexpressed three times more Tbeta 10 had 23-33% more polymerized actin than control cells, and the filaments appeared thicker after staining with fluorescent phalloidin. There was no change in total actin, profilin, and cofilin/actin depolymerizing factor content. The overexpressing cells were more motile; they spread faster and had higher chemotactic and wound healing activity. Assuming that there is no compensatory inactivation of the other classes of monomer binding proteins, our paradoxical observation can be accounted for quantitatively by a parallel in vitro study (Carlier, M.-F., Didry, D., Erk, I., Lepault, J., Van Troys, L., Vanderkekove, J., Perelroizen, I., Yin, H. L., Doi, Y., and Pantaloni, D., (1996) J. Biol. Chem. 271, 9231-9239). beta-Thymosin at levels comparable with that found in the overexpressing cells binds actin filaments and decreases the critical concentration (C(c)) for actin polymerization. This reduces the monomer buffering ability of beta-thymosin, so that above a certain threshold an incremental increase in thymosin does not lead to a corresponding increase in G-actin. Furthermore, the decrease in C(c) reduces the buffering capacity of the other actin monomer binding proteins. As a consequence, an increase in beta-thymosin does not necessarily result in a proportionate increase in actin monomer content in a complex environment containing other actin monomer binding proteins. The outcome depends on the level of beta-thymosin expression relative to the composition of the other actin monomer binding protein. Our results suggest that beta-thymosins are not simple actin buffering proteins and that their biphasic action may have physiological significance.

Effects of CapG overexpression on agonist-induced motility and second messenger generation

Actin modulating proteins that bind polyphosphoinositides, such as phosphatidylinositol 4, 5-bisphosphate (PIP2), can potentially participate in receptor signaling by restructuring the membrane cytoskeleton and modulating second messenger generation through the phosphoinositide cycle. We examined these possibilities by overexpressing CapG, an actin filament end capping, Ca(2+)- and polyphosphoinositide-binding protein of the gelsolin family. High level transient overexpression decreased actin filament staining in the center of the cells but not in the cell periphery. Moderate overexpression in clonally selected cell lines did not have a detectible effect on actin filament content or organization. Nevertheless, it promoted a dose-dependent increase in rates of wound healing and chemotaxis. The motile phenotype was similar to that observed with gelsolin overexpression, which in addition to capping, also severs and nucleates actin filaments. CapG overexpressing clones are more responsive to platelet-derived growth factor than control-transfected clones. They form more circular dorsal membrane ruffles, have higher phosphoinositide turnover, inositol 1,4,5-trisphosphate generation and Ca2+ signaling. These responses are consistent with enhanced PLC gamma activity. Direct measurements of PIP2 mass showed that the CapG effect on PLC gamma was not due primarily to an increase in the PIP2 substrate concentration. The observed changes in cell motility and membrane signaling are consistent with the hypothesis that PIP(2)-binding actin regulatory proteins modulate phosphoinositide turnover and second messenger generation in vivo. We infer that CapG and related proteins are poised to coordinate membrane signaling with actin filament dynamics following cell stimulation.

Actin monomer binding proteins

Small actin monomer binding proteins are essential components of the actin polymerization machinery. Originally thought of as passive buffers that prevent polymerization of actin monomers, recent discoveries elucidate how some actin monomer binding proteins can promote as well as inhibit polymerization, and how they cooperate to regulate actin assembly.

The actin side-binding domain of gelsolin also caps actin filaments. Implications for actin filament severing

Gelsolin is an actin filament-severing and -capping protein which is inhibited by polyphosphoinositides (PPI). Severing requires gelsolin binding to the side of the filaments through a site in segments 2 and 3 (S2-3) to position another site in segment 1 (S1) to sever filaments. In this paper, we report that S2-3, like S1, caps actin filaments. Since neither S1 and S2-3 caps as well as gelsolin, and neither severs actin filament, S2-3 may actively contribute to severing by capping filaments cooperatively with S1. We used deletional mutagenesis to locate the S2-3 sequence required for actin filament side binding, capping, and PPI binding and found that these sites are located close to the NH2 terminus of S2 (residues 161-172). S3, a segment which has no known function up to now and does not by itself bind actin, contributes to stable capping and may contain an additional PPI-binding site.

Control of follicle-stimulating hormone and luteinizing hormone release by hypothalamic peptides

Lesion, stimulation, and pharmacological studies point to separate hypothalamic control of pulsatile FSH and LH secretion. LH release is controlled by a region extending from the preoptic area to the anterior and mid-median eminence, whereas FSH release is controlled by a region extending from the dorsal anterior hypothalamic area to the caudal median eminence. We have separated an FSH-releasing factor from LHRH by gel-filtration on Sephadex G-25, confirming results obtained over 25 years ago; and we are attempting its isolation in collaboration with Vale and River. In the meantime, reasoning that FSH-releasing factor might be related to LHRH, we tested many analogs of LHRH and found one that has selective FSH-releasing activity over a 50-fold dose range; however, it is relatively weak. This led us to the possibility that the GAP might be FSH-RF. Indeed, GAP1-13 has FSH but no LH-releasing activity over a 100-fold dose range; however, it is less potent than we would expect of the natural product. Substituting D-Trp-9 into the molecule to inhibit enzymatic degradation yielded a more potent and completely selective FSH-releasing peptide,24 which could be clinically useful. Alpha-inhibin-92 of Li et al. has been shown to have a highly selective dose-related suppressive action on FSH release in castrate male rats.25 Smaller fragments (35-65 and 66-92) of this molecule also possess the activity, albeit at higher doses. That this molecule may be physiologically significant is indicated by elevations in plasma FSH in immature rats obtained following intravenous injection of antisera raised against the peptide. Because of its much smaller size than that of 32-kDa alpha, beta inhibins and the lack of carbohydrate in the molecule, this can be relatively easily synthesized and might have clinical utility as an FSH release-inhibiting peptide.

Identification of a polyphosphoinositide-binding sequence in an actin monomer-binding domain of gelsolin

Gelsolin is an actin filament-severing and -capping protein that has profound effects on actin filament organization and assembly. It is activated by Ca2+ and inhibited by polyphosphoinositides (PPI). We have previously shown that PPI inhibit actin filament severing by the amino-terminal half of gelsolin and hypothesized that this is mediated through inhibition of actin filament side binding (by domains II-III of gelsolin), a requisite first step in severing. In this paper, we report that the subsequent step in severing, which is mediated by an actin monomer binding site located in domain I of gelsolin, is also regulated by PPI. We used deletional mutagenesis and a synthetic peptide to locate the sequence required for high affinity PPI binding in domain I. Our results show that the PPI-binding sequence has a basic charge distribution that is also present in the PPI-regulated actin filament side binding domain, and the two gelsolin PPI-binding sites have similar PPI-binding affinities. In addition, a similar motif is present in several other PPI-binding proteins, including a highly conserved region in the phospholipase C family. We propose that the sequences identified in gelsolin may represent a consensus for PPI binding in a variety of proteins.