An investigation into the correlation between visual performance in simulated complex environments and academic attainment among primary school students

Traditional vision screenings in schools are limited to simple visual tasks, yet students in their daily learning face more complex visual environments. Binocular rivalry tasks can partially simulate the visual challenges of real visual environments and activate advanced visual processing mechanisms that simple visual tasks cannot. Therefore, by superimposing binocular rivalry-state tasks onto simple visual tasks, we have developed an innovative vision screening program to rapidly and extensively assess students' visual performance in complex environments. This is a cross-sectional study in which we investigated the performance of 1126 grade 1-6 students from a primary school in Wuxi, China, in rivalry-state stereoscopic vision tasks. The correlation between the screening results of 1044 students and their academic achievements was also statistically analyzed. The study results revealed pass rates of 53.5-60.5% across various visual tests. Specifically, for first-grade students, there was a statistically significant difference in standardized Chinese scores between the group that failed and the group that passed the rivalry-state stereoscopic vision test (- 0.49 ± 3.42 vs. 0.22 ± 0.58, t =  - 2.081, P = 0.04). This result underscores the importance of focusing on the visual adaptability of first graders in complex environments.Trail registration: Ethics Committee of Affiliated Children's Hospital of Jiangnan University-Certificate number: WXCH2022-04-027.

[Related factors of successful endovascular therapy in patients with chronic internal carotid artery occlusion]

The clinical data of 73 symptomatic patients with chronic internal carotid artery occlusion (CICAO) who underwent endovascular therapy in the Second Affiliated Hospital of Soochow University and Suzhou Ninth People's Hospital from January 2011 to May 2019 were retrospectively analyzed, and the related factors of successful endovascular therapy were determined. The patients were divided into recanalization group (49 cases) and non-recanalization group (24 cases). The related factors of successful endovascular recanalization in patients with symptomatic CICAO were investigated by both univariate and multivariate logistic regression analyses. The results showed that distal ICA reconstitution at the clinoid segment (OR=8.946, 95%CI: 1.782-44.910) and tapered stump (OR=4.488, 95%CI: 1.147-17.566) were related factors of successful endovascular therapy in patients with CICAO (both P<0.05). However, calcification at the beginning of occluded ICA (OR=0.161, 95%CI: 0.027-0.965) was an adverse factor for successful endovascular therapy in patients with CICAO (P<0.05). This study indicates that the related factors of successful ICA endovascular therapy in patients with symptomatic CICAO mainly include tapered stump and distal ICA reconstitution at the clinoid segment, while calcification at the beginning of occluded ICA was an adverse factor.

[Related factors of internal border-zone infarcts in patients with symptomatic chronic internal carotid artery occlusion]

Objective: To explore the related factors of internal border-zone (IBZ) infarcts in patients with symptomatic chronic internal carotid artery occlusion (CICAO). Methods: From January 2011 to May 2019, the symptomatic CICAO patients in the Second Affiliated Hospital of Soochow University and the Ninth People's Hospital of Suzhou were retrospectively analyzed. The patients were divided into IBZ group and non-IBZ group. The demographic data, laboratory examination and imaging data of the two groups were collected. Binary logistic regression analysis was used to identify the related factors of IBZ infarcts in patients with symptomatic CICAO. Results: A total of 185 patients (147 males and 38 females) were finally enrolled, with a mean age of (65±11) years old. There were 64 and 121 cases in IBZ group and non-IBZ group, respectively. The ratio of patients with ophthalmic artery (OA) reflux in IBZ group was 64.1% (41/64), which was significantly higher than that in non IBZ group [47.8% (55/121), P=0.037], while the ratio of patients with collateral compensation (ASTIN/SIR 3-4) in non-IBZ group was 66.1% (80/121), which was significantly higher than that in IBZ group [29.7% (19/64), P<0.001]. Multivariate logistic regression analysis showed that history of cerebral infarction (OR=2.233, 95%CI: 1.023-4.874), low density lipoprotein (LDL) (OR=1.516, 95%CI: 1.006-2.285) and OA reflux (OR=5.060, 95%CI: 1.160-22.081) were independent risk factors for IBZ infarcts in patients with symptomatic CICAO (all P<0.05); while prothrombin international normalized ratio (INR) (OR=0.010, 95%CI: 0.000-0.970) and collateral compensation (ASTIN/SIR 3-4) (OR=0.172, 95%CI: 0.079-0.373) were protective factors (all P<0.05). Conclusion: OA reflux, LDL, and history of cerebral infarction are independent risk factors for IBZ infarcts in patients with symptomatic CICAO, while INR and collateral compensation scores (ASTIN/SIR 3-4) are the protective factors.

[Spatio-temporal dynamics of gross primary productivity in China from 1982 to 2017 based on different datasets]

Understanding the spatio-temporal variations of gross primary productivity (GPP) of terrestrial ecosystem and its relationship with climatic factors can provide important basis for vegetation restoration and protection. Based on meteorological data and three public GPP datasets (EC-LUE GPP, GLASS GPP, and NIRv GPP), we syste-matically analyzed the spatial-temporal variations of GPP and its response to climate change in China during 1982-2017. All the results based on the three GPP datasets showed that the annual and seasonal GPP in China increased annually from 1982 to 2017, with that in 1998 and 2002 significantly being higher than the average level during the study period, and that in 1989 and 1992 significantly being lower than the average annual GPP. From 1982 to 2017, GPP showed a significant upward trend in most regions of China, with the regions with significant increases accounting for 75.7%, 73.0%, and 69.6% of the whole study area, respectively. There was a significant positive correlation between annual GPP and precipitation and temperature, but spatial heterogeneity was strong. Among them, the regions with positive correlation between GPP and temperature were mainly distributed in Northwest and Central China, while the regions with positive correlation between GPP and precipitation were mainly distributed in North China. There was obvious spatial-temporal heterogeneity in regions that GPP being affected by temperature and precipitation in different seasons. Temperature was the limiting factor of GPP in spring, autumn and winter, while summer GPP was mainly affected by precipitation.

[Clinical effects of anterograde sural neurovascular flap in repairing skin and soft tissue defect around the knee]

Objective: To explore the clinical effects of anterograde sural neurovascular flap in repairing skin and soft tissue defect around the knee. Methods: Nine patients with skin and soft tissue defect around the knee admitted to Beijing Fengtai YouAnMen Hospital from May 2011 to December 2018, were included in this retrospective descriptive study, including 8 males and 1 female, aged 16 to 65 years. The wound area after debridement ranged from 8 cm×5 cm to 18 cm×10 cm. Anterograde sural neurovascular flap was used to repair the wounds in 9 patients, with the area ranging from 9 cm×6 cm to 20 cm×12 cm. The donor sits of flaps in 2 patients were closed and sutured directly, and the donor sits of flaps in 7 patients were repaired with medial split-thickness skin graft of the ipsilateral thigh. The flap survival, complications, and follow-up after operation were recorded. Results: The flaps survived and the blood supply was good in 8 patients and the wounds were closed. One patient developed skin ischemic necrosis which was cured after three weeks of dressing change. All the skin grafts in the donor site of flap in 7 patients survived. In 6 months to 5 years of follow-up after surgery, the skin flap had good texture, color, and shape, and normal sensation. Except for one patient whose knee had poor recovery of function, the knee joint function of the other patients recovered well. Conclusions: The anterograde sural neurovascular flap has the advantages of high survival rate, satisfactory appearance and functional recovery post surgery, and is an ideal flap for repairing the skin and soft tissue defect around the knee.

[Clinical observational study of Nimotuzumab combined with concurrent chemoradiotherapy in the treatment of locally advanced cervical cancer]

Objective: To investigate the clinical efficacy and safety of Nimotuzumab combined with concurrent chemoradiotherapy in the treatment of locally advanced cervical cancer. Methods: A total of 65 patients with locally advanced cervical cancer treated with Nimotuzumab combined with concurrent chemoradiotherapy in Tianjin Medical University Cancer Institute and Hospital were selected from January 2015 to November 2018. Intensity-modulated radiotherapy and intracavitary post-packaging were used for radiation therapy. Platinum and paclitaxel were used for chemotherapy. Nimotuzumab were 400 mg/week. The clinical efficacy, the changes of serum tumor markers and the occurrence of adverse events were observed for 2 years, and the evaluation was performed once for every 3 months. Results: Sixty-one cases could be evaluated by imaging during the follow-up. The best curative effect evaluation showed that complete remission (CR) was 43 (70.5%), partial remission (PR) was 9 (14.8%), stable disease (SD) was 6 (9.8%) and objective response rate (CR+PR) was 85.3%, disease control rate (CR+PR+SD) was 95.1%. Survival analysis showed that one-year overall survival rate was 93.9% and two-year overall survival rate was 79.6%. After 3 months of treatment, the serum tumor markers SCC, CA125, CEA, and HE4 were significantly lower than those before treatment (P<0.05). Safety assessments showed that the main adverse events were hematochezia, abdominal pain, diarrhea, fever and dizziness, and 37 cases of them were grades Ⅰ-Ⅱ. Conclusion: Nimotuzumab combined with concurrent chemoradiotherapy has a good clinical effect in the treatment of locally advanced cervical cancer, significantly reduces serum tumor marker levels after treatment, and is safe and tolerable in clinical use.

[A Meta-analysis on the association between sleep duration and metabolic syndrome in adults]

Objective: To quantitatively evaluate the relationship between sleep duration and metabolic syndrome in adults in order to set up programs on prevention and treatment of metabolic syndrome in this population. Methods: Relevant studies were identified by systematically searching databases before October 2019. All statistical analyses were under the use of Stata 11.0. Results: A total of 656 319 participants including 150 638 cases with metabolic syndrome were involved in thes 38 articles. A U-shaped relationship between sleep duration and metabolic syndrome was noticed. For short and long sleep duration, the OR=1.11 (95%CI: 1.07-1.16) and 1.10 (95%CI: 1.03-1.18), respectively. Subgroup analyses on cross-sectional studies revealed that factors as men, aged under 60 years, being Asians or Caucasians would increase the risk of metabolic syndrome by 6%, 14%, 9%, and 24%, respectively for those with short sleep duration. Factors as aged 60 years and above, being black and with long sleep duration, would increase the risks of metabolic syndrome by 13% and 19%, respectively in women. In subgroup analyses on cohort studies, positive correlation between short sleep duration and metabolic syndrome was observed in both Asian (RR=1.10, 95%CI: 1.07-1.13) and in Caucasians (RR=1.56, 95%CI: 1.08-2.26) populations. Conclusions: Results of this study revealed an association between metabolic syndrome and the duration of sleep. We understand that sleep is a behavior that can be changed step by step, through adequate intervention programs, to reduce the risk of metabolic syndrome which has become an important public health issue.

Application of Artificial Intelligence Automatic Diatom Identification System in Practical Cases

Abstract

Objective To discuss the application of artificial intelligence automatic diatom identification system in practical cases, to provide reference for quantitative diatom analysis using the system and to validate the deep learning model incorporated into the system. Methods Organs from 10 corpses in water were collected and digested with diatom nitric acid; then the smears were digitally scanned using a digital slide scanner and the diatoms were tested qualitatively and quantitatively by artificial intelligence automatic diatom identification system. Results The area under the curve （AUC） of the receiver operator characteristic （ROC） curve of the deep learning model incorporated into the artificial intelligence automatic diatom identification system, reached 98.22% and the precision of diatom identification reached 92.45%. Conclusion The artificial intelligence automatic diatom identification system is able to automatically identify diatoms, and can be used as an auxiliary tool in diatom testing in practical cases, to provide reference to drowning diagnosis.

[Investigation of temporal and spatial characteristics of allergic rhinitis epidemics by Baidu Index in China]

Objective: To explore the temporal and spatial characteristics of search volume (SV) of allergic rhinitis (AR) and related search terms on Baidu Index, as well as the correlation between SV from Baidu Index and epidemiology of AR. Methods: SV of AR and related search terms in mainland area of China from January 2012 to December 2016 were extracted from Baidu Index. Firstly, we investigated the temporal and spatial characteristics of SV of AR and related search terms ("pollen allergy" and" dust mite allergy", etc.), and explored the correlation between SV of AR and SV of related search terms. Secondly, the SV of specific search terms in Beijing and Guangzhou were compared with the actual pollen count in Beijing from April to September in 2016 and the monthly outpatient volume of AR patients in the Otorhinolaryngology Hospital, The First Affiliated Hospital of Sun Yat-sen University from 2014 to 2016 respectively to analyze the consistency between SV from Baidu Index and the real-world data. Spearman correlation analysis was used to explore the correlation between different search terms according to the normality and homogeneity of variance of the data. P<0.05 was considered statistically significant. Results: SV of AR showed repetitively seasonal pattern, with the first peak in May and the second peak from August to September. SV of AR in northeast China, north China and northwest China were correlated with both SV of "pollen allergy" and "dust mite allergy" (r value was 0.533, 0.638, 0.609, 0.791, 0.517, 0.682, respectively, all P<0.05). In east China, central China, south China and southwest China, SV of AR showed significant correlation only with SV of "dust mite allergy" (r value was 0.897, 0.884, 0.799, 0.937, respectively, all P<0.05), but not with SV of "pollen allergy" (r value was 0.110, 0.171, 0.020, 0.265, respectively, all P>0.05). The correlation between pollen count and the SV of AR on the day and SV of "pollen allergy" on the next day was the highest (r value was 0.692 and 0.713, respectively, all P<0.05). The SV of AR was correlated with the monthly outpatient volume of AR patients one month and two months later (r value was 0.523 and 0.503, respectively, all P<0.05). Conclusion: The SV of AR and related search terms show different trends in different times and regions which are consistent with the AR epidemiological survey, and significantly correlate with pollen count and AR outpatient volume.

[Clinical analysis of carotid artery stenting with severe stenosis and extracranial distortion under proximal protection technique]

Objective: To investigate the feasibility, efficacy and safety of endovascular reconstruction of the carotid artery with severe stenosis and extracranial distortion under proximal protection. Methods: A retrospective analysis of 21 patients with severe carotid stenosis and extracranial distortion who were admitted to the Second Affiliated Hospital of Soochow University between January 2011 and August 2017, of which 16 patients were symptomatic stenosis with acute ischemic stroke. All the patients were treated with carotid artery stenting under (CAS) proximal protection technique, and assessed with the National Institutes of Health Stroke Scale (NIHSS) before the treatment and hospital discharge. The clinical outcome and vascular morphology were followed-up regularly after the treatment. Results: Twenty-one patients were successfully completed the CAS procedure under the proximal protection technique, the average blocking time was 241.0 (232.5-261.0) seconds. Nine patients received 1block attempt, 6 patients received 2 block attempts, and the other 6 patients received 3 block attempts. Three patients experienced transient ischemic attack (TIA) during the procedure, the maximum duration of TIA was 10 minutes. In 16 patients with symptomatic stenosis, there were no significant differences in NIHSS score before CAS procedure and hospital discharge (P>0.05). The residual stenosis rate of the carotid artery after stenting was(13±6)%, compared with preoperative (87±16)%, which appeared a significant difference (t=19.948, P<0.05). All the patients had no adverse events such as myocardial infarction, recurrent ischemic stroke and death in the follow-up period. Restenosis was assessed in 6 patients by DSA or CTA and no restenosis was found. Conclusion: Endovascular reconstruction of the carotid artery with severe stenosis and extracranial distortion under proximal protection technique has been proven as a safe and effective therapy.

[Comprehensive treatment on ten patients with perianal necrotizing fasciitis]

Ten patients with perianal necrotizing fasciitis were admitted to our department from June to December 2016. There were 8 men and 2 women among the patients, aged 42 to 69 years. Early and complete debridement surgery and comprehensive supportive treatment during perioperative period were carried out to quickly stabilize the patient's overall condition, and wounds were sutured directly or repaired with autologous scalps and or adjacent local random flaps. After debridement, wound areas ranged from 10 cm×8 cm to 54 cm×21 cm, and area of the flap was about 8 cm×5 cm. The donor site of flap was sutured directly. After the operation, all skin grafts and the flap survived, and wounds of all patients healed. During follow-up of six months to one year, there was no recurrence of perianal necrotizing fasciitis, and functions of the involved lower extremities didn't be influenced.

[Prevalence, awareness, treatment and control of hypertension in elderly residents in Hebei province]

Objective: To understand the prevalence, awareness, treatment and control of hypertension in elderly residents in Hebei province. Methods: Elderly residents aged ≥60 were selected though multistage clustering sampling during August to December, 2015. Design based methods were adopted to analyze the prevalence, awareness, treatment and control of hypertension in local residents of Hebei. Results: A total of 2 501 elderly adults were included in the study. The overall prevalence rate of hypertension was 63.7% (58.3% in males, 69.0% in females), the awareness rate of hypertension was 42.4% (35.7% in males, 48.0% in females), the treatment rate was 38.2% (32.0% in males, 43.3% in females), and the control rate was 9.0% (8.1% in males, 9.7% in females). The results of multivariate analysis indicated that age, sex, degree of education, BMI and central obesity were the factors influencing the prevalence, awareness, treatment and control of hypertension in elderly population in Hebei. Conclusions: The prevalence of hypertension was high, but the rates of awareness, treatment and control of hypertension were low in elderly residents in Hebei. The influences of overweight, obesity and central obesity on hypertension were significant in the elderly. It is necessary to standard the management of hypertension and reduce the risk factors for hypertension in elderly population to improve the control of hypertension.

[A survey on night sleep quality and daytime tiredness among shift nurses in a tertiary teaching hospital]

Objective: To explore the night sleep quality of shift nurses and the current situation of their daytime tiredness, sleepiness, and to provide evidence for nursing administrators and managers to allocate human resources reasonably and prevent adverse events. Methods: The cross-sectional method was utilized to conduct a questionnaire survey among shift nurses in a tertiary teaching hospital in Shandong Province from March to May inclusive, 2017. Results: There was a total of 233 valid questionnaires returned. The prevalence of sleep disorder, daytime tiredness and sleepiness was 45.92%, 16.31% and 13.30%, respectively. The differences of the nurses' sleep quality at night between different ages, marriages, educational backgrounds and professional titles were statistically significant (P<0.05) , while the differences of daytime burnout and sleep state between different shift systems were statistically significant (P<0.01) . Night sleep quality was positively correlated with daytime tiredness and sleepiness (P<0.05) . The results of multiple linear regression analysis showed that age, marriage, educational background and professional title had an impact on nurses' sleep quality at night (P<0.05) . Shift system had an impact on nurses' daytime burnout and sleep apnea (P<0.01) . Conclusion: There was a high prevalence of night sleep disorder, daytime tiredness and sleepiness among the shift nurses. Nursing administrators and managers should pay more attention to the night sleep quality of nurses who aged over 30 years old, married, without a bachelor degree and those with a lower professional rank. Furthermore, the current situation of daytime tiredness and sleepiness among two-shift only nurses was worrisome.

[One case of elderly patient with extremely severe burn complicated by ventricular tachycardia]

One elderly patient with extremely severe burn was admitted to our department on 4th August, 2017. The patient suffered multiple sustained ventricular tachycardia from post injury day 2 to 4 due to relatively high input volume during shock stage. Amiodarone could not be given through intravenous injection because of his low blood pressure. After consultation with cardiologist, ventricular tachycardia was corrected by electrical cardioversion of several times. According to this case, the first treatment is electrical cardioversion when elderly patient with extremely severe burn shows sustained ventricular tachycardia which can not be corrected with medicine.

[Prevalence of diabetes in adults in Hebei province]

Objective: To understand the prevalence of diabetes in adults in Hebei province. Methods: The survey was conducted among the local residents aged ≥18 years, who were selected through multi stage cluster sampling from September 2013 to April 2014. Design-based methods were used to analyze the prevalence in the last 12 months. Results: A total of 7 678 adults were included in the study. The overall prevalence of diabetes in Hebei was 12.9% (13.1% in men and 12.8% in women), there was no sex specific difference in diabetes prevalence (P=0.09). The prevalence was higher in urban residents (16.2%) than that in rural residents (12.1%), the difference was significant (P<0.01). The prevalence of diabetes increased with age (P<0.01). The prevalence of impaired fasting glucose was 5.1%, the difference was significant between men and women and between rural area and urban area (P<0.01). The prevalence of impaired glucose tolerance was 10.4%. The difference of prevalence of impaired glucose tolerance in men and women and between rural area and urban area was not significant. The rates of awareness, treatment and control of diabetes were 50.7%, 46.3% and 37.5%, respectively. Women had higher awareness rate and treatment rate of diabetes than men, the difference was significant (P<0.01). Conclusions: The prevalence of diabetes was high in adults in Hebei province, the difference in diabetes prevalence between urban area and rural area was significant. The prevalence of impaired fasting glucose and impaired glucose tolerance were high, but the rates of awareness, treatment and control of diabetes were low.

Meta-analysis of IL-6 -174G/C polymorphism and psoriasis risk

Previous studies examining the association between interleukin-6 (IL-6) -174G/C polymorphism and psoriasis risk have produced inconsistent results. The aim of this study was to offer a comprehensive review of the association between IL-6 -174G/C polymorphism and psoriasis risk through a meta-analysis. Literature search of PubMed and Embase databases was conducted to identify all eligible studies published before October 29, 2015. Four case-control studies involving 651 psoriasis cases and 552 controls were included in this meta-analysis. Data were extracted, and pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to assess the associations. Combined analysis revealed a significant association between this polymorphism and psoriasis risk under the recessive model (OR = 1.69, 95%CI = 1.12-2.55, P = 0.013 for GG vs GC + CC), and the heterozygous comparison model (OR = 1.70, 95%CI = 1.29-2.23, P < 0.001 for GG vs GC). However, no significant association was observed under the allelic model (OR = 1.37, 95%CI = 0.99-1.89, P = 0.060 for G vs C), the dominant model (OR = 1.25, 95%CI = 0.92-1.71, P = 0.152 for GG + GC vs CC), and the homozygote comparison model (OR = 1.62, 95%CI = 0.79-3.32, P = 0.186 for GG vs CC). We conclude that the IL-6 -174G/C polymorphism contributes to psoriasis risk. However, further studies should be performed to validate our results.

In situ detection of salicylic acid binding sites in plant tissues

The determination of hormone-binding sites in plants is essential in understanding the mechanisms behind hormone function. Salicylic acid (SA) is an important plant hormone that regulates responses to biotic and abiotic stresses. In order to label SA-binding sites in plant tissues, a quantum dots (QDs) probe functionalized with a SA moiety was successfully synthesized by coupling CdSe QDs capped with 3-mercaptopropionic acid (MPA) to 4-amino-2-hydroxybenzoic acid (PAS), using 1-ethyl-3-(3-dimethyllaminopropyl) carbodiimide (EDC) as the coupling agent. The probe was then characterized by dynamic light scattering and transmission electron microscopy, as well as UV/vis and fluorescence spectrophotometry. The results confirmed the successful conjugation of PAS to CdSe QDs and revealed that the conjugates maintained the properties of the original QDs, with small core diameters and adequate dispersal in solution. The PAS-CdSe QDs were used to detect SA-binding sites in mung bean and Arabidopsis thaliana seedlings in vitro and in vivo. The PAS-CdSe QDs were effectively transported into plant tissues and specifically bound to SA receptors in vivo. In addition, the effects of the PAS-CdSe QDs on cytosolic Ca(2+) levels in the tips of A. thaliana seedlings were investigated. Both SA and PAS-CdSe QDs had similar effects on the trend in cytosolic-free Ca(2+) concentrations, suggesting that the PAS-CdSe QDs maintained the bioactivity of SA. To summarize, PAS-CdSe QDs have high potential as a fluorescent probe for the in vitro/in vivo labeling and imaging of SA receptors in plants.

[Biosorption of chromium (VI) by waste biomass of epsilon-poly-L-lysine fermentation]

The sorption of hexavalent chromium by waste biomass of epsilon-Poly-L-lysine fermentation strains (Streptomyces albulus) PD-1 was studied. Effects of pretreatment ways, pH, initial concentration of Cr(VI), contact time and temperature on biosorption were determined. It was found that homogenization in HCl was the best way to pretreat mycelia, having an increased rate of Cr(VI) biosorption at 22.7%, the optimum pH was about 2.0, while no significant impact of temperature on the biosorption was observed. The fitness of the experimental data for the Langmuir and Freundlich adsorption models was further examined and good correlations with R2 of 0.979 4 and 0.979 8 were observed, indicating the presence of both monolayer biosorption and heterogeneous surface condition. The maximum adsorption capacity of the Streptomyces albulus PD-1 for Cr(VI) was 23.92 mg x g(-1). FT-IR analysis demonstrates that the major functional groups (amide and hydroxyl) may contribute to the absorption of Cr(VI).

A meta-analysis and systematic review of prophylactic endoscopic treatments for postpolypectomy bleeding

PURPOSE

The aim of this meta-analysis and systematic review was to determine whether bleeding prophylaxis benefits patients after colonoscopic polypectomy.

METHODS

A systematic review of the literature was performed to find prospective randomized controlled trials of postpolypectomy hemorrhage prophylaxis. Studies were selected according to specific criteria and analyzed to generate pooled data.

RESULTS

Eight studies encompassing 2,595 polyps met the criteria for the meta-analysis. The rate of early bleeding was significantly decreased relative to the control when a single prophylactic technique was used [2.58% vs. 8.15%, OR = 0.34 (95% CI, 0.20-0.58), P < 0.0001]. The use of multiple prophylactic techniques resulted in a lower early postpolypectomy hemorrhage rate compared with the use of a single prophylactic technique [0% vs. 8.41%, OR = 0.12 (95% CI, 0.03-0.47), P = 0.002]. The late bleeding rate did not differ significantly between the monotherapy and control groups [0.61% vs. 1.39%, OR = 0.37 (95% CI, 0.11-1.28), P = 0.12], and the use of combined preventative techniques did not significantly decrease the late postpolypectomy bleeding (PPB) rate compared with use of a single prophylactic method [1.43% vs. 2.05%, OR = 0.70 (95% CI, 0.32-1.55), P = 0.38].

CONCLUSION

Prophylactic endoscopic treatments are effective at reducing early PPB after colonoscopic polypectomy. However, patients with late PPB may not benefit from bleeding prophylaxis.

2,2′-(Biphenyl-4,4′-diyldioxy)diacetic acidN,N-dimethylformamide solvate

In the crystal struture of the title compound, C₁₆H₁₄O₆·C₃H₇NO, the two crystallographically independent benzene rings are coplanar [dihedral angle = 1.00 (2)°]. The crystal structure is stabilized by O—H⋯O hydrogen bonds between the diacid and the solvate dimethylformamide mol­ecule, resulting in the formation of a zigzag chain structure extending parallel to [001].

Effect of semen sampling frequency on seminal antiretroviral drug concentration

Study of male genital tract (MGT) pharmacology is relevant to the treatment of prostatitis, prostate cancer, infertility, and seminal human immunodeficiency virus transmission. However, the time course of drug concentrations in the MGT is largely unknown. To determine the feasibility of frequent semen sampling in assessing the pharmacokinetics of the MGT, we administered efavirenz, indinavir, and zidovudine to subjects to achieve steady-state levels and then collected semen samples at sequentially decreasing ejaculation intervals. The volume of seminal plasma decreased from 4.0 (1.2-5.1) ml (median with range) at 48 h after the baseline ejaculation to 0.72 (0.45-1.6) ml 1 h after a previous ejaculation, which was still adequate for drug concentration assessment. The seminal fructose concentration also decreased. However, the concentration of prostate-specific antigen and all three drugs did not decrease, even if the ejaculation intervals decreased to 1 h. Thus, semi-intensive semen sampling can be used to assess MGT pharmacokinetics.

Tetraspanin CD9 regulates invasion during mouse embryo implantation

The expression of tetraspanin CD9 was found on blastocysts in mice and endometrium epithelial cells in human and bovine. However, it remains unknown how CD9 is involved in the precise dialogue between embryo and uterus during early pregnancy. This study was designed to investigate the functional roles of CD9 in the embryo implantation with monoclonal antibody against CD9 protein (anti-CD9 mAb) and antisense oligonucleotide against CD9 gene (AS-CD9). Our results showed that intrauterine injection of anti-CD9 mAb on day 4 of pregnancy significantly increased the number of embryos implanted (7.24+/-0.39 versus 4.04+/-0.38). In vitro, anti-CD9 mAb or AS-CD9 significantly enhanced embryo-outgrowth ability on the monolayer of uterus epithelial cells in a dose-dependent manner. However, the attachment of blastocysts to epithelial cells was unaffected. Furthermore, we found that anti-CD9 mAb or AS-CD9 stimulated matrix metalloproteinase 2 (MMP-2) production of blastocysts on Fibronectin. LY294002, a specific inhibitor of phosphoinositide 3-kinase, was able to counteract the effect of anti-CD9 mAb and AS-CD9 on outgrowth ability and production of MMP-2. Our results indicated that CD9 played a role of inhibiting embryo implantation. CD9 was able to impair embryo invasion and the production of MMP-2 through the phosphoinositide 3-kinase signaling pathway.

Effects of anandamide on embryo implantation in the mouse

Anandamide (N-arachidonoylethanolamine), an arachidonic acid derivative, is an endogenous ligand for both the brain-type (CB1-R) and spleen-type (CB2-R) cannabinoid receptors. To investigate the possible effects of anandamide on embryo implantation in the mouse, we used a co-culture system in which mouse embryos are cultured with a monolayer of uterine epithelial cells. Our results indicate that 14 nM anandamide significantly promotes the attachment and outgrowth of the blastocysts on the monolayer of uterine epithelial cells, and those effects could be blocked by CB1-R antagonists SR141716A, but not by SR144528, a CB2-R antagonist. It suggests that the effects of anandamide on embryo attachment and outgrowth are mediated by CB1-R. However, 56 nM anandamide is capable of inhibiting the blastocyst attachment and outgrowth, we, therefore, conclude that anandamide may play an essential role at the outset of implantation.

Hypoxia-inducible transgene expression in differentiated human NT2N neurons--a cell culture model for gene therapy of postischemic neuronal loss

Expression of anti-apoptotic or neurotrophic transgene proteins in hypoxic neurons may provide a novel therapeutic strategy for neuroprotection and alleviation of damage to ischemic brain areas. NT2, a human neoplastic cell line which terminally differentiates into postmitotic neurons (NT2N) by treatment with retinoic acid was used in this study as a cell culture model for human neuronal cells. The hypoxia-inducible VEGF promoter in plasmid vectors was employed to drive the expression of marker genes (luciferase) and therapeutic genes (bcl2) in hypoxic NT2 cells and NT2N neurons in culture. Cationic liposomes complexed with plasmid DNA were used for transfection of vectors with the constitutive cytomegalovirus promoter (pCMV) or the hypoxia-inducible VEGF promoter (pHRE). Hypoxic or normoxic control NT2 cells transfected with pCMV-luciferase showed high transgene expression (2.4 x 10(8) relative light units (RLU)/mg protein). Control NT2 cells transfected with pHRE-luciferase had a rather low activity (4.9 x 10(6) RLU/mg protein), which was induced 34-fold under hypoxic conditions. Four-fold induction of luciferase expression was obtained in hypoxic NT2N neurons transfected with pHRE compared with normoxic controls. The hypoxia-induced luciferase expression in NT2N cells was 34% of the activity of pCMV-luciferase under the same conditions. Transfection of NT2N neurons with pCMV-bcl2 or pHRE-bcl2 was demonstrated to reduce significantly the numbers of apoptotic cells after hypoxia. These results demonstrate efficient VEGF promoter-mediated induction of transgene expression in hypoxic human neurons. This cell culture model may be employed for the further investigation of therapeutic proteins against ischemic brain damage due to neuronal loss.

[The improvement and discussion of the model of focal cerebral ischemia/reperfusion with suture-occluded method in rats]

AIM

To supply a simple method of the model of focal cerebral ischemia/reperfusion in rats.

METHODS

Zea Longa's suture-occluded method was improved and the comparison between the two methods was made in rCBF, the scores of neurological deficit and infarct volume.

RESULTS

There were not significant differences between our improved method and Zea Longa's method in rCBF, the scores of neurological deficit and infarct volume.

CONCLUSION

The model of focal cerebral ischemia/ reperfusion with our improved method was also stable and established more easily than that with Zea Longa's method.

Effects of leukaemia inhibitory factor on embryo implantation in the mouse

Leukaemia inhibitory factor (LIF) is a pleiotrophic cytokine. Recent reports indicate that LIF is relevant to murine embryo implantation. In this work, results of indirect immunofluorescence under a confocal microscope illustrated that LIF was mainly located in the uterine lumen and uterine epithelial cells in pregnant mice on day 4. The number of embryos implanted in pregnant mice on day 8 decreased significantly after injection of 3 microg LIF antibodies into a uterine horn (P<0.001), which demonstrated again that LIF is a critical factor for embryo implantation. In a co-culture system, LIF (0.1 ng/ml, 1 ng/ml, 10 ng/ml and 100 ng/ml) significantly enhanced the blastocyst outgrowth after 24, 48 or 72 h of co-culture, and outgrowth areas after 72 h of co-culture. Conversely, 5 microg/ml and 10 microg/ml, but not 1 microg/ml, LIF antibodies decreased the percentage of blastocysts with outgrowth; only 10 microg/ml LIF antibody inhibited blastocyst outgrowth area significantly (P<0.001). However, neither LIF nor its antibodies changed embryo attachment. Analysis of correlation showed that the effects of LIF or its antibodies on the blastocyst outgrowth were dose-dependent. In summary, different pathways may exist to regulate the blastocyst attachment and outgrowth on a monolayer of uterine epithelial cells. LIF protein from the maternal uterus exerts an essential role in embryo implantation in the mouse, which is mediated by stimulating trophoblast outgrowth, but not by promoting the attachment.

A mutation in the second intracellular loop of the pituitary adenylate cyclase activating polypeptide type I receptor confers constitutive receptor activation

The pituitary adenylate cyclase activating polypeptide (PACAP) type I receptor belongs to the glucagon/secretin/vasoactive intestinal polypeptide (VIP) receptor family. We mutated and deleted an amino acid residue (E261) which is located within the second intracellular loop of the rat PACAP type I receptor and which is highly conserved among the receptor family. The wild-type receptor and the mutant receptors were efficiently expressed at the surface of COS-7 cells at nearly the same level and revealed the same high affinity for the agonist PACAP-27. The cAMP contents of COS cells transfected with the E261A, E261Q, and the deletion mutant receptor were 4.6-, 5.7-, and 6.7-fold higher as compared with COS cells transfected with the wild-type receptor. Thus, all the mutant PACAP receptors were constitutively active. The data suggest that the glutamic acid in the second intracellular loop of the PACAP receptor may be a key residue to constrain the receptor in the inactive conformation with respect to its coupling to G(s) proteins.

Patch-clamp analysis of anesthetic interactions with recombinant SK2 subtype neuronal calcium-activated potassium channels

Small conductance calcium-activated potassium channels (SK) mediate spike frequency adaptation and underlie the slow afterhyperpolarization in central neurons. We tested the actions of several anesthetics on the SK2 subtype of recombinant SK channels, cloned from rat brain and functionally expressed in a mammalian cell line. Butanol, ethanol, ketamine, lidocaine, and methohexital blocked recombinant SK2 channel currents, measured in the whole-cell patch clamp recording mode. The block was reversible, dose-dependent, and of variable efficacy. The inhaled anesthetics chloroform, desflurane, enflurane, halothane, isoflurane, and sevoflurane produced little or no block when applied at 1 minimum alveolar anesthetic concentration; varying degrees of modulation were observed at very large concentrations (10 minimum alveolar concentration). The extent of block by inhaled anesthetics did not appear to depend on concentration or membrane voltage.

IMPLICATIONS

We describe differential effects of anesthetics on cloned small conductance calcium-activated potassium channels from brain that may play a role in generating the effects or side effects of anesthetics.

Production and characterization of monoclonal antibodies to pituitary adenylate cyclase activating polypeptide type I receptor

Pituitary adenylate cyclase activating polypeptide type I receptor (PACAPr) belongs to the novel subfamily of the G-protein coupled receptors with a long extracellular N-terminus, which functions as a major binding site for the PACAP. Three different N-terminal fragments of rat PACAPr were overexpressed in Escherichia coli and purified using His-tags or maltose-binding protein as anchors for affinity chromatography. The purified and refolded proteins were used for the production and screening of monoclonal antibodies (MAbs) to PACAPr. Fifteen hybridoma cell lines producing MAbs specific to PACAPr were generated and characterized. Epitope analysis by competitive enzyme-linked immunoadsorbent assay (ELISA) indicated the presence of two groups of overlapping epitopes in the N-terminal fragment of PACAPr. Reactivity of MAbs with SDS-denaturated and native rat PACAPr was demonstrated by immunoblotting and flow cytometric analysis using transiently transfected COS cells and stably transfected CHO cells expressing rat PACAPr. Each antibody was examined by immunoblotting for the ability to cross react with the human PACAPr in human neuroblastoma NB-OK cells and most of them were shown to recognize human PACAPr as effectively as rat PACAPr. MAbs against the N-terminal extracellular domain of PACAPr can be used for the immunochemical study of the receptor-ligand interaction and for the investigation of PACAPr distribution in normal and tumor tissues.

Caffeine and carbonyl cyanide m-chlorophenylhydrazone increased evoked and spontaneous release of luteinizing hormone-releasing hormone from intact presynaptic terminals

In bullfrog sympathetic ganglia, the ryanodine-sensitive Ca2+ store and mitochondria modulate [Ca2+] within nerve terminals. We used caffeine (10 mM) and carbonyl cyanide m-chlorophenylhydrazone (10 microM) to assess how these Ca2+ stores affect release of a neuropeptide, luteinizing hormone-releasing hormone, from these nerve terminals. Release of luteinizing hormone-releasing hormone was evoked by electrical stimulation to presynaptic nerves and was monitored as a late slow excitatory postsynaptic potential in ganglionic neurons. Caffeine increased release of luteinizing hormone-releasing hormone similarly whether the release was evoked by 4 or 20 Hz stimulations (by 2.7 +/- 1.1- and 3.2 +/- 0.9-fold, mean +/- S.E.M., n = 27, respectively). Carbonyl cyanide m-chlorophenylhydrazone augmented release of luteinizing hormone-releasing hormone evoked by 4 Hz stimulation much more strongly (by 11.8 +/- 1.8-fold) than it increased the release evoked by 20 Hz stimulation (by 3.6 +/- 1.3-fold, n = 25). We detected spontaneous release of luteinizing hormone-releasing hormone as a slow hyperpolarization in response to a brief application of an antagonist to the receptors for luteinizing hormone-releasing hormone in 65% (34 of 52) and 39% (11 of 28) of the ganglionic B and C neurons, respectively. Caffeine increased spontaneous release of luteinizing hormone-releasing hormone by 2.3 +/- 0.7-fold (n = 6) whereas carbonyl cyanide m-chlorophenylhydrazone increased this release by 4.27- and 1.76-fold (n = 2). Facilitation of Ca2+ release from the intracellular store by caffeine and inhibition of mitochondrial Ca2+ removal by carbonyl cyanide m-chlorophenylhydrazone increased spontaneous as well as evoked release of luteinizing hormone-releasing hormone. Moreover, caffeine increments of evoked release did not depend on the firing frequency of the nerve whereas carbonyl cyanide m-chlorophenylhydrazone augmentations of evoked release strongly depended on the firing frequency.

Activation of recombinant human SK4 channels by metal cations

The effects of metal cations on the activation of recombinant human SK4 (also known as hIK1 or hKCa4) channels, expressed in HEK 293 cells, were tested using patch clamp recording. Of the nine metals tested, cobalt, iron, magnesium, and zinc did not activate the SK4 channels when applied, at concentrations up to 100 microM, to the inside of SK4 channel-expressing membrane patches. Barium, cadmium, calcium, lead, and strontium activated SK4 channels in a concentration-dependent manner. The rank order of potency was at Ca2+ > Pb2+ > Cd2+ > Sr2+ > Ba2+.

Identification of binding domains of pituitary adenylate cyclase activating polypeptide (PACAP) for its type 1 receptor by photoaffinity labeling

Structure-function studies and photoaffinity labeling experiments were performed to identify residues and domains of PACAP involved in the interaction with PACAP receptors. For this purpose, a series of photoreactive analogues of PACAP(1-27) containing a photoreactive benzophenone (BP) residue in different peptide structural domains were utilized to analyze the interaction of PACAP(1-27) with pig PACAP type 1 receptors. Five PACAP derivatives were created with a photoreactive amino acid in the following peptide domains: either the disordered N-terminal or the helical C-terminal domain or a short loop region within the C-terminal helical domain of the peptide. Their receptor binding properties and efficiencies were tested on pig brain PACAP receptors. The results indicate the importance of the helical C-terminal domain of PACAP(1-27) for receptor binding affinity. Monoiodination of the photoreactive analogues did not change their binding affinities. Experiments with pig brain membranes demonstrated that the 125I-labeled photoreactive analogues specifically label a protein band of M(r) 66,000. The efficiency of photoreactive labeling differed for the various analogues. These findings suggest that Tyr22 and Lys15 in PACAP (1-27) are located in or close to the hormone binding site of the PACAP type 1 receptor. The results provide evidence that the alpha-helical C-terminal region of PACAP is directly involved in receptor binding.

Activation of nicotinic receptor-induced postsynaptic responses to luteinizing hormone-releasing hormone in bullfrog sympathetic ganglia via a Na+-dependent mechanism

Nicotine at very low doses (5-30 nM) induced large amounts of luteinizing hormone-releasing hormone (LHRH) release, which was monitored as slow membrane depolarizations in the ganglionic neurons of bullfrog sympathetic ganglia. A nicotinic antagonist, d-tubocurarine chloride, completely and reversibly blocked the nicotine-induced LHRH release, but it did not block the nerve-firing-evoked LHRH release. Thus, nicotine activated nicotinic acetylcholine receptors and produced LHRH release via a mechanism that is different from the mechanism for evoked release. Moreover, this release was not caused by Ca2+ influx through either the nicotinic receptors or the voltage-gated Ca2+ channels because the release was increased moderately when the extracellular solution was changed into a Ca2+-free solution that also contained Mg2+ (4 mM) and Cd2+ (200 microM). The release did not depend on Ca2+ release from the intraterminal Ca2+ stores either because fura-2 fluorimetry showed extremely low Ca2+ elevation (approximately 30 nM) in response to nicotine (30 nM). Moreover, nicotine evoked LHRH release when [Ca2+] elevation in the terminals was prevented by loading the terminals with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid and fura-2. Instead, the nicotine-induced release required extracellular Na+ because substitution of extracellular NaCl with N-methyl-D-glucamine chloride completely blocked the release. The Na+-dependent mechanism was not via Na+ influx through the voltage-gated Na+ channels because the release was not affected by tetrodotoxin (1-50 microM) plus Cd2+ (200 microM). Thus, nicotine at very low concentrations induced LHRH release via a Na+-dependent, Ca2+-independent mechanism.

Effects of monoclonal antibody directed to LeY on implantation in the mouse

The role of carbohydrates in embryo implantation in the mouse was investigated using an embryo transfer model and a blastocyst-uterine epithelial cell co-culture system. The monoclonal antibody (mAb) AH6 directed to LeY oligosaccharide (Fuc alpha1-2 Gal beta 1-4 [Fuc alpha1-3] GlcNAc) and other three mAbs directed to carbohydrates whose structures are closely related to LeY were used to show the effect of carbohydrate specificity on implantation. In the embryo transfer model, donor blastocysts (4 days post-coitus) were pretreated with mAb AH6 (experimental) or other mAbs (control) and transferred into one uterine horn of a recipient. The implantation rate was checked after 5 days. Implantation was significantly inhibited by mAb AH6 pretreatment, and inhibition was not observed in control groups. In the co-culture system, the attachment and outgrowth rate of blastocysts on the surface of uterine epithelial cells was significantly inhibited when monolayer epithelial cells or blastocysts were pretreated with mAb AH6. The most obvious effect of mAb AH6 was obtained during 2-4 h co-incubation. No inhibition was observed in the control groups. It was, therefore, concluded that oligosaccharide LeY recognized by mAb AH6 plays an essential role at the initial stage of implantation. It may act as a mediator molecule for adhesion between the surface of blastocyst and epithelial cell, and its function is carbohydrate-specific.

Effect of chronic administration of [D-Pen2, D-Pen5] enkephalin on the activity of nitric oxide synthase in brain regions and spinal cord of mice

The effect of multiple intracerebroventricular (i.c.v.) injections of [D-Pen2, D-Pen5]enkephalin (DPDPE), a delta-opioid receptor agonist, on the activity of nitric oxide synthase (NOS) was determined in the brain regions and spinal cord of the mouse. Male Swiss Webster mice were injected twice daily with DPDPE (20 micrograms/mouse, i.c.v.) or its vehicle for 4 days. This procedure has previously been shown to induce tolerance to the antinociceptive actions of DPDPE in mice. On day 5, the animals treated with DPDPE were either sacrificed 20 min after an i.c.v. injection of DPDPE (tolerant) or without any injection (abstinent i.e., 16 h after the last injection of DPDPE). NOS activity in brain regions (cortex, striatum, hippocampus, midbrain, pons/medulla, hypothalamus and cerebellum) and spinal cord was determined by the rate of conversion of arginine into citrulline. Tolerance to DPDPE was associated increases in NOS activity in midbrain (49%) and pons/medulla (32%) and decreases in cerebellum (28%) and spinal cord (44%). However, NOS activity was unchanged in the cortex, corpus striatum, hippocampus and hypothalamus. On the other hand, during abstinence from DPDPE, NOS activity increased in midbrain (84%) and hypothalamus (35%) but decreased in cerebral cortex (27%) cerebellum (27%) and spinal cord (20%). NOS activity was unchanged in the corpus striatum, hippocampus and pons/medulla. Previous studies from this laboratory had demonstrated that chronic administration of mu- and kappa-opioid receptor agonists results in increases NOS activity in certain brain regions and that tolerance to mu- and kappa-, but not to delta-opioid receptor agonists, is attenuated by NOS inhibitors. The present studies, for the first time, demonstrate decreases in NOS activity in certain brain regions and spinal cord of mice treated chronically with delta-opioid receptor agonist. Furthermore, these findings may explain the inability of NOS inhibitors to attenuate tolerance to DPDPE in mice.

Interactions of cocaine with morphine, U-50,488H and [D-Pen2, D-Pen5]enkaphalin

The effects of acute and chronic administration of cocaine on the antinociception and tolerance to the antinociceptive actions of mu-(morphine), kappa-(U-50,488H), and delta-([D-Pen2,D-Pen5]enkephalin; DPDPE), opioid receptor agonists were determined in male Swiss-Webster mice. Intraperitoneal injection of 40 mg/kg of cocaine by itself produced weak antinociceptive response as measured by the tail-fick test but the lower doses were ineffective. Administration of morphine (10 mg/kg, SC), U-50,488H (25 mg/kg, IP) or DPDPE (10 microg/mouse, ICV) produced antinociception in mice. Cocaine (20 mg/kg) potentiated the antinociceptive action of morphine and DPDPE but had no effect on U-50,488H-induced antinociception. Administration of morphine (20 mg/kg, SC), U-50,488H (25 mg/kg, IP) or DPDPE (20 microg/mouse, ICV) twice a day for 4 days resulted in the development of tolerance to their antinociceptive actions. Tolerance to the antinociceptive actions of morphine and U-50,488H was inhibited by concurrent treatment with 20 or 40 mg/kg doses of cocaine; however, tolerance to the antinociceptive action of DPDPE was not modified by cocaine. It is concluded that cocaine selectively potentiates the antinociceptive action of mu- and delta- but not of the kappa-opioid receptor agonist. On the other hand, cocaine inhibits the development of tolerance to the antinociceptive actions of mu- and kappa- but not of delta-opioid receptor agonists in mice.

Effects of noribogaine on the development of tolerance to antinociceptive action of morphine in mice

The effects of noribogaine, a metabolite of ibogaine, on the development of tolerance to the antinociception action of morphine was determined in male Swiss-Webster mice. Ibogaine is an alkaloid isolated from the bark of the African shrub, Tabernanthe iboga. Morphine tolerance in mice was developed by two different methods. Mice were rendered tolerant to morphine either by subcutaneous implantation of a pellet containing 25 mg morphine free base for 4 days or by injecting morphine (20 mg/kg, s.c.) twice a day for 4 days. Placebo pellet implanted mice or vehicle injected mice served as controls. To determine the effect of intraperitoneally administered noribogaine on tolerance development, the drug was injected in the appropriate dose twice a day. In pellet implanted mice, a dose of 20 mg/kg of noribogaine attenuated the tolerance to morphine whereas lower doses had no effect. Similarly, in mice given multiple injections of morphine, noribogaine attenuated tolerance development at 20 and 40 mg/kg doses. Previous studies from this laboratory had shown that ibogaine at 40 and 80 mg/kg doses inhibited tolerance to morphine. Because noribogaine could attenuate morphine tolerance at lower doses than ibogaine, it is concluded that the attenuating effect of ibogaine on morphine tolerance may be mediated by its conversion to noribogaine, a more active metabolite.

Effects of NMDA receptor antagonists on delta1- and delta2-opioid receptor agonists-induced changes in the mouse brain [3H]DPDPE binding

Male Swiss-Webster mice were injected intracerebroventricularly (i.c.v.) with [D-Pen2,D-Pen5]enkephalin (20 microg/mouse) twice a day for 2 days. This procedure resulted in down-regulation of binding sites for [3H][D-Pen2,D-Pen5]enkephalin as evidenced by a 52% decrease in the Bmax value. Twice daily injections of (+)-5-methyl-10,11-dihydro-5H-dibenzo-[a,d]-cyclohepten-5,10-imine (MK-801) (0.1 mg/kg, i.p.) or [(-)3-SR,4a-RS,8a-SR-6-(phosphonomethyl)-1,2,3,4,4a,5,6,7,8,8a-decahy droisoquinoline-3-carboxylic acid] (LY 235959) (2 mg/kg, i.p.), the noncompetitive and competitive antagonist of the N-methyl-D-aspartate (NMDA) receptor, respectively, for 2 days did not alter the Bmax or Kd value of [3H][D-Pen2,D-Pen5]enkephalin binding to the mouse brain. Concurrent treatment of MK-801, but not of LY 235959 with [D-Pen2,D-Pen5]enkephalin, reversed the decreases in Bmax value of [3H][D-Pen2,D-Pen5]enkephalin. Twice daily injections of [D-Ala2,Glu4] deltorphin II (20 microg/mouse) for 2 days caused an increase in the Kd value, but not the Bmax value of [3H][D-Pen2,D-Pen5]enkephalin to bind to brain membranes. Concurrent treatment of [D-Ala2,Glu4]deltorphin II with LY 235959 reversed the increase in Kd value of [3H][D-Pen2,D-Pen5]enkephalin binding induced by multiple injections of [D-Ala2,Glu4]deltorphin II, but MK-801 had no effect. The results suggest that multiple injections of delta1- and delta2-opioid receptor agonists down-regulate delta1-opioid receptors of the brain by modifying Bmax and Kd values of [3H][D-Pen2,D-Pen5]enkephalin binding, respectively. MK-801 and LY 235959 reverse delta1- and delta2-opioid receptor agonists-induced down-regulation of brain delta1-opioid receptor, respectively, apparently by different mechanisms. It is concluded that short term treatment of mice with delta1-opioid receptor agonist down-regulates brain delta1-opioid receptors by decreasing Bmax of the ligand which is partially reversed by concurrent treatment with MK-801 but not by LY 235959. On the other hand, short term treatment of mice with delta2-opioid receptor agonist down-regulates brain delta1-opioid receptors by increasing Kd of the ligand which is partially reversed by concurrent treatment with LY 235959 but not by MK-801.

Effects of ibogaine on the development of tolerance to antinociceptive action of mu-, delta- and kappa-opioid receptor agonists in mice

The effects of ibogaine, an alkaloid isolated from the bark of the African shrub, Tabernanthe iboga, on the development of tolerance to the antinociception action of morphine, U-50,488H and [D-Pen2,D-Pen5]enkephalin (DPDPE), which are mu-, kappa- and delta-opioid receptor agonists, respectively, were determined in male Swiss-Webster mice. Mice were rendered tolerant to opioid receptor agonists by injecting morphine (20 mg/kg, s.c.), U-50,488H (25 mg/kg, i.p.) or DPDPE (20 microg/mouse, i.c.v.) twice a day for 4 days. Ibogaine (20, 40 or 80 mg/kg, i.p.) given twice a day for 4 days did not alter the tail-flick latency. Ibogaine (40 or 80 mg/kg, i.p.) injected 10 min before each injection of morphine inhibited the development of tolerance to the antinociceptive action of morphine, however, the lower dose of ibogaine (20 mg/kg, i.p.) was ineffective. Ibogaine (20, 40 or 80 mg/kg, i.p.) given prior to the injection of U-50,488H or DPDPE did not modify the development of tolerance to their antinociceptive action. It is concluded that ibogaine inhibits selectively the development of tolerance to the antinociceptive action of mu- but not kappa- or delta-opioid receptor agonists in mice.

Effects of ibogaine and noribogaine on the antinociceptive action of mu-, delta- and kappa-opioid receptor agonists in mice

Ibogaine, an alkaloid isolated from the bark of the African shrub, Tabernanthe iboga, has been claimed to decrease the self-administration of drugs of abuse like morphine, cocaine and alcohol. To determine whether these effects are mediated via opioid receptor systems, the effects of ibogaine and its metabolite, noribogaine on the antinociceptive actions of morphine, U-50,488H and [D-Pen2,D-Pen5]enkephalin (DPDPE) which are mu- kappa- and delta-opioid receptor agonists, respectively, were determined in male Swiss-Webster mice. Administration of morphine (7 or 10 mg/kg, s.c.), U-50,488H (15 or 25 mg/kg, i.p.) or DPDPE (10 microg/mouse, i.c.v.) produced antinociception in mice as measured by the tail-flick test. Ibogaine (10, 20 or 40 mg/kg, i.p.) by itself did not alter the tail-flick latency. The same doses of ibogaine injected 10 min before the opioid drugs did not modify the antinociceptive actions of morphine, U-50,488H or DPDPE. Ibogaine administered 4 h or 24 h prior to morphine injection did not modify the antinociceptive action of the latter. A dose of 40 mg/kg (i.p.) of noribogaine enhanced the antinociceptive activity of morphine (10 mg/kg, s.c.). Similarly, the doses of 40 and 80 mg/kg of noribogaine enhanced the antinociception produced by a smaller dose of morphine (5 mg/kg, s.c.). However, antinociception induced by U-50,488H and DPDPE was not modified by noribogaine (10-40 mg/kg). It is concluded that ibogaine, which has been suggested to decrease the self-administration of cocaine and opiates like heroin in humans, does not produce such an action by interacting directly with multiple opioid receptors. However, the metabolite of ibogaine enhances the antinociception of morphine but not of U-50,488H or DPDPE. Thus, in vivo evidence has been provided for the possible interaction of ibogaine with mu-opioid receptor following its metabolism to noribogaine.

Photoaffinity labeling analysis of the interaction of pituitary adenylate-cyclase-activating polypeptide (PACAP) with the PACAP type I receptor

To identify residues and domains of the peptide hormone pituitary adenylate-cyclase-activating polypeptide (PACAP) that interact with the type I receptor, two photoreactive analogues of PACAP-(1-27)-peptide were synthesized using solid-phase peptide synthesis. Phe6 or Tyr22 within the PACAP sequence were replaced by p-benzoyl-L-phenylalanine (Bz-Phe) thus creating two PACAP derivatives with a photoreactive amino acid in either the disordered N-terminal or the helical C-terminal part of the peptide. The ligand-binding properties and the efficiencies of these peptide analogues as photolabels were tested for pig brain PACAP receptors. [Bz-Phe6]-PACAP-(1-27)-peptide (Kd 1.3 nM) retained the high binding affinity of PACAP-(1-27)-peptide (Kd 0.5 nM), wheras Bz-Phe substitution of Tyr22 reduced the affinity about tenfold (Kd 4.4 nM) thus demonstrating the importance of Tyr22 for receptor binding. Monoiodination of the photoreactive analogues did not change the binding affinity of the photoreactive analogues. Photoaffinity labeling using pig brain membrane demonstrated that the 125I-labeled photoreactive analogues specifically label a 66000-Mr protein band. Photoaffinity labeling of the rat brain PACAP receptor expressed in COS cells resulted in two specifically photolabeled proteins: a major band of Mr 58000 and a minor band of Mr 78000. By treatment of photolabeled membranes with N-glycosidase F, both of the polypeptide bands were converted to a single polypeptide band of Mr 54000, which corresponds to the deglycosylated PACAP receptor. Despite its lower receptor affinity, [Bz-Phe22]-PACAP-(1-27)-peptide labeled the PACAP type I receptor in pig brain membranes and the rat receptor expressed in COS cells with much higher efficiency (20-fold for the pig receptor) than [Bz-Phe6]-PACAP-(1-27)-peptide. These findings suggest that Tyr22 in PACAP-(1-27)-peptide is located in or close to the hormone-binding site of the PACAP type I receptor. The results provide evidence that the alpha-helical C-terminal region of PACAP is directly involved in receptor binding.

Effect of chronic administration of morphine, U-50, 488H and [D-Pen2, D-Pen5]enkephalin on the concentration of cGMP in brain regions and spinal cord of the mouse

The effects of chronic administration and subsequent withdrawal of mu-, kappa- and delta-opioid receptor agonists on the levels of cyclic GMP in several brain regions and spinal cord of mice were determined in an attempt to further study the role of NO cascade in opioid actions. The agonists at mu-, kappa- and delta-opioid receptor included morphine, U-50,488H and DPDPE, respectively. Tolerance to morphine was associated with highly significant increases in cGMP levels in corpus striatum (41%), cortex (36%), midbrain (73%) and cerebellum (51%) relative to controls. Abstinence caused increases in cGMP levels in corpus striatum (61%) and pons and medulla (45%). Tolerance to U-50,488H resulted in increases in cGMP levels in midbrain (52%) whereas abstinence from U-50,488H increased the cGMP levels in pons and medulla (76%). Tolerance to DPDPE was associated with increases in cGMP levels in hypothalamus (12%) and pons and medulla (33%) but decreases in cerebellum (66%) and spinal cord (58%). Abstinence from DPDPE produced increases in cGMP levels in pons and medulla (14%) but decreases in cerebellum (67%) and spinal cord (50%). Overall treatment with morphine and U-50,488H produced increases in cGMP levels in brain regions whereas DPDPE produced decreases in brain regions and spinal cord. Previous studies have shown that chronic administration of mu- and kappa-opioid receptor agonists induce NO synthase (NOS) in certain brain regions and that the inhibitors of NO synthase attenuate tolerance to mu- and kappa- but not to delta-opioid receptors agonists. Since activation of NO increases the production of cGMP, the present results demonstrating alterations of cGMP levels by mu-, kappa- and delta-opioid receptor agonists are consistent with the behavioral results with NOS inhibitors on tolerance to mu-, kappa- and delta-opioid receptor agonists.

Effect of 7-nitroindazole on tolerance to morphine, U-50,488H and [D-Pen2, D-Pen5] enkephalin in mice

The effects of 7-nitroindazole (7-NI), an inhibitor of the neuronal nitric oxide synthase (nNOS) which does not increase blood pressure, on tolerance to the antinociceptive activity of mu-(morphine), kappa-(U-50,488H) and delta-([D-Pen2, D-Pen5]enkephalin, DPDPE) opioid receptor agonists were determined in mice. Male Swiss-Webster mice were made tolerant by twice daily injections of morphine (20 mg/kg, s.c.), U-50,488H (25 mg/kg, i.p.) or DPDPE (20 micrograms/mouse, i.c.v.) for 4 days. When tested on day 5, tolerance to their antinociceptive activity was evidenced by decreased response in chronic drug treated mice in comparison to vehicle-injected mice. Concurrent administration of 7-NI (20, 40 or 80 mg/kg, i.p.) with DPDPE did not modify the development of tolerance to the antinociceptive action of DPDPE. However, 7-NI (40 or 80 mg/kg, i.p.) inhibited the development of tolerance to the antinociceptive activity of morphine and U-50,488H but the lower dose of 7-NI (20 mg/kg, i.p.) was not effective. Chronic administration of 7-NI by itself did not modify the acute response to morphine, U-50,488H or DPDPE. It is concluded that a specific inhibitor of nNOS can inhibit tolerance to the antinociceptive activity of mu- and kappa- but not of delta-opioid receptor agonists in mice.

[Studies of murine ectoplacental cone cells interaction with laminin]

Implantation of the mouse embryo is dependent on the interactions between the trophoblast cells and the surrounding uterine environment. The initial invasion by primary trophoblast stimulates the uterine stromal fibroblasts differentiate into decidual cells, which deposit a pericellular matrix consisting of LN, FN and Col IV. The secondary trophoblast giant cells (TGCs) from ectoplacental cone (EPC) invade the decidua to form the fetal portion of the placenta. We used synthetic peptides cyclic YIGSR (cYIGSR) and RGDS to study the mechanisms of EPC cells interaction with LN. The results indicated that cYIGSR and RGDS promoted EPC attachment and had synergistic effect, and cYIGSR also promoted EPC outgrowth and secondary TGCs migration. LN supported EPC attachment and outgrowth, as well as secondary TGCs migration from EPC. Biologically active domains RGD of LN A chain and YIGSR of LN B1 chain participated synergistically in EPC attachment, outgrowth, as well as secondary TGCs migration. Since synthetic peptides cYIGSR and RGDS can't competitively inhibit EPC attachment with LN completely, there must be other binding sites involved in the interaction.

The amino-terminal fragment of the adenylate cyclase activating polypeptide (PACAP) receptor functions as a high affinity PACAP binding domain

The PACAP receptor represents a member of a novel subfamily of G-protein coupled receptors with a common structurally conserved extracellular domain of about 150 amino acids. We have addressed the question whether this extracellular amino-terminus of the PACAP type I receptor can solely function as a PACAP binding domain. For that purpose a cDNA was constructed that encodes the membrane-anchored amino-terminus of the rat PACAP receptor including the decapeptide epitope EQKLISEEDL for immunodetection. COS-7 cells were transfected with this cDNA and a comparable construct of the wild-type receptor. Binding analysis showed that the amino-terminal fragment of the PACAP receptor bound PACAP with high-affinity (Kd = 3.8 nM; Bmax = 12.8 pmol/mg protein). In comparison to the full-length receptor (Kd = 0.2 nM; Bmax = 1.96 pmol/mg protein) its affinity was reduced by a factor of about 20. The results suggest that the amino-terminus of the PACAP receptor functions as the major binding site for its ligand.

Molecular structure analysis of the pituitary adenylate cyclase activating polypeptide type I receptor from pig brain

In pig brain a type I receptor for pituitary adenylate cyclase activating polypeptide (PACAP) has been identified and structurally characterized. Scatchard analysis of the equilibrium binding data indicates a single class of binding sites with Kd of 0.50 nM and Bmax of 2.52 pmol/mg. The receptors could be efficiently solubilized with 3-[(3-cholamidopropyl)dimethylammonio]-2-hydroxy-1- propanesulfonate (Chapso) without altering their ligand binding parameters (Kd = 0.60 nM; Bmax = 2.46 pmol/mg). In both preparations the ligand-receptor complex was identified as a 68 kDa polypeptide by affinity crosslinking with 125I-PACAP-27 and disuccinimidyl suberate. Employment of nonreducing conditions decreased the electrophoretic mobility of the complex to a 60 kDa species suggesting that the native PACAP receptor exists in a compact conformation stabilized by intramolecular disulfide bridges. Disulfide bonds are also important for the ligand binding activity of the PACAP receptor since pretreatment of the membranes with dithiothreitol led to complete inhibition of PACAP binding and to 61% dissociation of the ligand-receptor complex. Among different sulfhydryl selective reagents tested, p-chloromercuriphenylsulfonic acid was found to inhibit PACAP binding to its receptor in a dose-dependent fashion (IC50 = 0.5 mM) suggesting that one or more sulfhydryl groups are located close to the ligand binding domain of the receptor. Desialylation of the affinity-labeled PACAP receptor with neuraminidase revealed a 61 kDa protein, whereas deglycosylation with N-glycosidase F decreased the M(r) to 52,000. Chromatography on a series of lectin agaroses showed the highest affinity for wheat germ agglutinin (WGA). WGA was also effective in dose-dependent inhibition of PACAP binding activity. Our results characterize the pig PACAP receptor as a tri- or tetraantennary non- or low fucosylated complex type glycoprotein with a protein core of about 49 kDa containing several terminal sialyl residues.

Preparation and crystallization of human transthyretin (prealbumin) variants

Naturally occurring variants of human serum transthyretin (prealbumin) have been prepared by recombinant DNA methods and crystallized from ammonium sulfate solutions to give crystals suitable for x-ray crystallographic analysis. Included are variants which are known to be associated with familial amyloidotic polyneuropathy. Dyes which have been used as histochemical stains to identify amyloid tissue deposits: Congo Red, Methylene Blue and Bromophenol Blue, have been co-crystallized with the transthyretin variants. Congo Red was found to be very selective while Methylene Blue actually assisted in the formation of crystals. All crystal forms which were examined were isomorphous to the structure of normal transthyretin.