[Risks to predict blood loss and cranial nerve injury in carotid body paraganglioma resection]

Objective: To investigate clinical and imaging parameters to predict blood loss and cranial nerve injury (CNI) following carotid body paraganglioma (CBP) resection. Methods: A retrospective examination of clinical and imaging data was conducted on 63 patients who underwent CBP resection at Xiangya Hospital of Central South University from January 2016 to December 2022, including 23 males and 40 females, aged 26-87 years old. Three imaging parameters including tumor volume, the angle of contact with the internal carotid artery (ICA), and the distance to the base of skull (DTBOS) were gauged using the IMEDPACS software on CTA and MR imaging. The predictive efficacies of age, gender, Shamblin classification, and three imaging parameters for blood loss and CNI following surgery were analysed. Logistic composite parameter models were constructed and their predictive validity was assessed. Results: Multivariate logistic regression analysis underscored that only tumor volume (OR=1.381,95%CI:1.167-1.507,P=0.001) showed significant statistical correlations with blood loss following surgery. Area under curve (AUC) values of 0.910 for receiver operating characteristic (ROC) curves showed a sensitivity of 1.000 and a specificity of 0.694. Tumor volume (OR=1.126,95%CI:1.030-1.231, P=0.002) and DTBOS (OR=0.225,95%CI:0.081-0.630,P=0.005) were significantly associated with postoperative CNI. The analysis of logistic composite model showed AUC values for tumor volume, DTBOS and combination of the two parameters were 0.858, 0.788, and 0.872, respectively. The model for combination of tumor volume and DTBOS also proved superior in predicting postoperative CNI (Z=3.106, P<0.001), with a sensitivity of 0.833 and a specificity of 0.769. Conclusions: Tumor volume and DTBOS emerged as effective predictors for blood loss and/or CNI in patients with CBP resection. Moreover, the logistic composite parameter model outclassed single-parameter models in terms of their predictive clinical value.

[The association of renalase single-nucleotide polymorphisms rs2576178 and rs10887800 with hypertension in patients with obstructive sleep apnea]

Objective: To evaluate the associations between the renalase single-nucleotide polymorphisms rs2576178 and rs10887800 and the risk of hypertension in OSA patients. Methods: A total of 3, 570 male OSA subjects diagnosed via standard polysomnography were included in this retrospective study. We recorded anthropometric, genomic, and polysomnographic parameters and blood pressure levels. All subjects were divided into four groups based on quartiles of the apnea-hypopnea index (AHI). The relationships between rs2576178 and rs10887800 and the risk of hypertension were evaluated using the binary logistic regression, and haplotype analysis. Results: In the bottom AHI quartile, rs10887800 was significantly associated with the risk of hypertension according to the dominant model [odds ratio(OR)=0.691, 95% confidence interval (CI)=0.483-0.990, P=0.044] even after adjustment for age, sex, and the body mass index. The G-A haplotype was associated with a co-effect of the two SNPs, namely, the risk of hypertension decreased (OR=0.879, 95%CI=0.784-0.986, P=0.028). Conclusions: We find no association between single rs2576178 or rs10887800 variants with the risk of hypertension in our OSA population. But, the synergistic effect of the two polymorphisms is associated with the risk of hypertension in OSA patients.

[Factors affecting BK polyomavirus infection after kidney transplantation in post-school children and a predictive infection model]

Objective: To analyze high-risk factors affecting BK polyomavirus (BKPyV) infection and to construct a prediction model for BKPyV infection in children after renal transplantation. Methods: The clinical data of 332 children who received allogeneic kidney transplantation in the First Affiliated Hospital of Zhengzhou University from January 2014 to March 2022 were retrospectively collected. According to the BKPyV load level, the dynamic change process of lymphocytes at different time points were analyzed. The factors that have potential influence on BKPyV infection were screened by Cox regression analysis, and the receiver operating characteristic curve (ROC) was used to evaluate the sensitivity and specificity of the predictive model of infection. Results: Among the 332 children, there were 215 males and 117 females; the age of transplantation was (12.2±3.9) years old; 37 cases were preschool (1-5 years old), and 295 cases were post-school age (6-18 years old). BKPyV load in 224 urine samples and 30 blood samples of children were detected. There were 9 cases of BKPyV-associated viruria and 3 cases of BKPyV associated viremia in pre-school children, 76 cases BKPyV associated viruria and 14 cases of BKPyV associated viremia in post-school children. Multivariate Cox regression analysis showed that higher body mass index (BMI) (HR=1.105, 95%CI: 1.020-1.197), antithyroglobulin (ATG) application (HR=2.196, 95%CI: 1.335-3.613), and higher tacrolimus concentration (HR=2.484, 95%CI: 1.298-4.753), higher natural killer (NK) lymphocyte count (HR=1.193, 95%CI: 1.009-1.411), higher CD14⁺⁺CD16^-cell count (HR=1.096, 95%CI: 1.024-1.173) were independent risk factors for BKPyV associated viruria in post-school children. Delayed graft function (DGF) (HR=4.993, 95%CI: 1.555-16.038), Acute rejection (AR) (HR=6.021, 95%CI: 1.930-18.787), higher CD14⁺⁺CD16^-cell count (HR=1.227, 95%CI: 1.081-1.392) were independent risk factors for BKPyV associated viremia in post-school children. The results of ROC curve analysis showed that combined BMI, immune induction drugs, tacrolimus concentration, NK cell count, and CD14⁺⁺CD16^-cell count predicted the occurrence of BKPyV associated viruria in post-school children after kidney transplantation at 0.5, 1, 2, and 5 years with area under curve (AUC) of 0.712 (95%CI: 0.626-0.798), 0.708 (95%CI: 0.612-0.804), 0.754 (95%CI: 0.668-0.840) and 0.767 (95%CI: 0.685-0.849). The sensitivity and specificity of the model were 64.9%, 61.4%, 61.6%, 55.8% and 70.9%, 72.4%, 76.0%, 84.0%, respectively. Combined with DGF, AR, and CD14⁺⁺CD16^-cell counts predicted the occurrence of BKPyV-associated viremia at 0.5, 1, 2, and 5 years after renal transplantation in post-school children with AUC of 0.791 (95%CI: 0.631-0.951), 0.744 (95%CI: 0.547-0.936), 0.786 (95%CI: 0.629-0.946) and 0.812 (95%CI: 0.672-0.948). The sensitivity and specificity of the model were 76.1%, 67.1%, 75.0%, 77.9% and 88.9%, 89.0%, 89.9%, 88.0%, respectively. Conclusions: The postoperative CD14⁺⁺CD16^-cell level can be used as an independent predictor of BKPyV infection in post-school children after renal transplantation. Combined BMI, immune induction drugs, tacrolimus concentration, NK cell count, CD14⁺⁺CD16^-cell count and combined DGF, AR, CD14⁺⁺CD16^-cell count show good fitting effect in predicting the occurrence of BKPyV-associated viruria and viremia after transplantation in post-school children respectively.

[Analysis of prognostic factors of pediatric kidney transplantation]

Objective: To evaluate the short-and mid-term efficacy of pediatric kidney transplantation and the risk factors for kidney graft and recipient. Methods: The baseline data and postoperative complications of pediatric donors and recipients of 284 kidney transplants were retrospectively analyzed in the Department of Kidney Transplantation in the First Affiliated Hospital of Zhengzhou University from August 2010 to May 2021 and all subjects were followed up until December 31, 2021. According to the survival status of donors and recipients, they were divided into the graft-loss group and the graft-survival group, and the recipient death group and survival group, respectively. Univariate comparison between groups was performed by Log-rank test, and Cox proportional risk model was used to explore the independent risk factors for the graft and recipient survival. Results: Among the 284 children recipients, 184 cases (64.8%) were male and 100 cases(35.2%) were female, and 19 cases (6.7%) were living relative donor renal transplantation, 19 cases (6.7%) were preemptive transplantation, and 8 cases were secondary transplantation. The age of 284 recipients at the time of transplantation was 13.0 (9.0, 15.0) years, among whom 29 cases aged 0-6 years, 96 cases aged 7-11 years old, and 159 cases aged 12-18 years. The 1, 3, and 5 year survival rates were 92.3%, 88.9% and 84.8% for the kidney grafts, and were 97.1%, 95.6% and 94.4% for the recipients, respectively. Multivariate analysis showed postoperative acute rejection (HR=3.14, 95%CI 1.38-7.15, P=0.006) and perioperative vascular complications (HR=4.73, 95%CI 2.03-11.06, P<0.001) were independent risk factors for the survival of kidney graft. Postoperative infection (HR=14.23, 95%CI 3.45-58.72, P<0.001) was an independent risk factor for the postoperative mortality of recipients. Conclusions: Pediatric kidney transplantation shows a good short-and mid-term prognosis. Postoperative acute rejection and perioperative vascular complications are the risk factors for the survival of kidney graft, and postoperative infection is the risk factor affecting the survival of recipient.

Analysis of the pan-Asian subgroup of patients in the NALA Trial: a randomized phase III NALA Trial comparing neratinib+capecitabine (N+C) vs lapatinib+capecitabine (L+C) in patients with HER2+metastatic breast cancer (mBC) previously treated with two or more HER2-directed regimens

PURPOSE

Neratinib, an irreversible pan-HER tyrosine kinase inhibitor, has demonstrated systemic efficacy and intracranial activity in various stages of HER2+breast cancer. NALA was a phase III randomized trial that assessed the efficacy and safety of neratinib+capecitabine (N+C) against lapatinib+capecitabine (L+C) in HER2+ metastatic breast cancer (mBC) patients who had received ≥ 2 HER2-directed regimens. Descriptive analysis results of the Asian subgroup in the NALA study are reported herein.

METHODS

621 centrally assessed HER2+ mBC patients were enrolled, 202 of whom were Asian. Those with stable, asymptomatic brain metastases (BM) were eligible for study entry. Patients were randomized 1:1 to N (240 mg qd) + C (750 mg/m² bid, day 1-14) with loperamide prophylaxis or to L (1250 mg qd) + C (1000 mg/m² bid, day 1-14) in 21-day cycles. Co-primary endpoints were centrally assessed progression-free survival (PFS) and overall survival (OS). Secondary endpoints included time to intervention for central nervous system (CNS) disease, objective response rate, duration of response (DoR), clinical benefit rate, and safety.

RESULTS

104 and 98 Asian patients were randomly assigned to receive N+C or L+C, respectively. Median PFS of N+C and L+C was 7.0 and 5.4 months (P = 0.0011), respectively. Overall cumulative incidence of intervention for CNS disease was lower with N+C (27.9 versus 33.8%; P = 0.039). Both median OS (23.8 versus 18.7 months; P = 0.185) and DoR (11.1 versus 4.2 months; P < 0.0001) were extended with N+C, compared to L+C. The incidences of grade 3/4 treatment emergent adverse events (TEAEs) and TEAEs leading to treatment discontinuation were mostly comparable between the two arms. Diarrhea and palmar-plantar erythrodysesthesia were the most frequent TEAEs in both arms, similar to the overall population in incidence and severity.

CONCLUSION

Consistent with the efficacy profile observed in the overall study population, Asian patients with HER2+ mBC, who had received ≥ 2 HER2-directed regimens, may also benefit from N+C. No new safety signals were noted.

CLINICAL TRIAL REGISTRATION

NCT01808573.

[Study on mental health status of pregnant women and its influencing factors in the third trimester]

Objective: To understand the mental health status of pregnant women in the third trimester of pregnancy, and explore the influencing factors. Methods: The general demographic information and pregnancy information of 575 pregnant women in the Chinese Pregnant Women Cohort Study were collected. The mental health status of pregnant women in the third trimester was investigated by using Edinburgh Postpartum Depression Scale, Self-Rating Anxiety Scale and University of California at Los Angeles. Multivariate unconditional logistic regression was used to analyze the influencing factors for mental health of pregnant women. Results: In the third trimester of pregnancy, the incidence of depression was 16.52%, the incidence of anxiety was 11.13%, and the incidence of feeling loneliness was 26.26%. Logistic regression analysis showed that compared with those with education level of junior high school below, those with education level of college or bachelor's degree (OR=0.418, 95%CI: 0.184-0.950) and master's degree or above (OR=0.116, 95%CI: 0.027-0.503) were less likely to feel loneliness. Pregnant women with higher annual family income (10 000 RMB yuan) were less likely to suffer from depression (≥20 vs. <10: OR=0.527, 95%CI: 0.279-0.998), anxiety (10-20 vs. <10: OR=0.363, 95%CI: 0.180-0.731; ≥20 vs. <10: OR=0.271, 95%CI: 0.132-0.554) and feeling loneliness (≥20 vs. <10: OR=0.477, 95%CI: 0.276-0.826). Conclusions: The education level and family income have impacts on the mental health status of pregnant women in the third trimester. Medical staff should give targeted psychological advice to pregnant women to improve their mental health status.

[Effects of changes in physical activities on depressive symptoms during pregnancy: a cohort study]

Objective: To investigate the effect of changes in physical activities on depressive symptoms in the second trimester of pregnancy. Methods: Data from the Chinese Pregnant Women Cohort Study, from July 25, 2017 to November 26, 2018, were used. Women who had effectively completed the survey of physical activity and depressive symptoms in the first and second trimesters of pregnancy, were recruited. Both International Physical Activity Questionnaire-short and Edinburgh Postnatal Depression Scale were used, respectively. Pregnant women who had completed two surveys were included in our study and were divided into two groups according to the depressive symptoms, measured at the baseline. Among the pregnant women without depressive symptoms at the baseline, logistic regression was used to analyze the effects of changes in physical activity on the prevention of depressive symptoms. Effect on the reduction of depressive symptoms was analyzed, using the same method. Results: The prevalence rates of depressive symptoms were 23.83% and 20.57% in the baseline and second trimester, respectively. After adjusting for age, education level, occupation, family annual income and pre-pregnancy BMI, data from the logistic regression showed that women without depressive symptoms and with increased and adequate physical activities in the baseline, were with lower risks to develop depressive symptoms in the second trimester (OR=0.479, 95%CI: 0.335-0.684;OR=0.566, 95%CI: 0.394-0.815). Among women with depressive symptoms in the baseline survey, association between physical activity and depressive symptoms was not statistically significant (P>0.05). Conclusions: Increased and adequate physical activities showed preventive effects on depressive symptoms during pregnancy, but the remission effect was not obvious in women with depressive symptoms. Pregnant women should be encouraged to increase their physical activities while screening programs should also be carried out to reduce the depressive symptoms during pregnancy.

Frequent loss of CD10 expression in follicular lymphoma with leukaemic presentation

INTRODUCTION

Follicular lymphoma (FL) is usually a nodal lymphoma expressing CD10, rarely with leukaemic presentation (FL-LP).

MATERIALS AND METHODS

We searched for FL-LP in our institution from 2000 to 2018 and characterised the neoplastic cells by flow cytometry, immunohistochemistry and fluorescence in situ hybridization. Thirteen (6.1%) of 212 FL cases were FL-LP, all de novo neoplasms. The leukaemic cells were small in 12 cases and large in one. All had concurrent FL, mostly (92%; 12/13) low-grade. The single case with large leukaemic cells had a concurrent primary splenic low-grade FL and a double-hit large B-cell lymphoma in the marrow.

RESULTS

CD10 was expressed in the leukaemic cells in 38% (5/13) cases by flow cytometry and in 77% (10/13) cases in tumours (p= 0.0471). IGH/BCL2 reciprocal translocation was identified in 85% (11/13) cases. Most patients were treated with chemotherapy. In a median follow-up time of 36 months, nine patients were in complete remission. The 2- and 5-year survival rates were at 100% and 83%, respectively. In this study, we characterised a series of de novo FL-LP in Taiwan. All patients had concurrent nodal and/or tissue tumours, which might suggest that these patients seek medical help too late.

CONCLUSION

The lower CD10 expression rate by flow cytometry than by immunohistochemistry might be due to different epitopes for these assays. Alternatively, loss of CD10 expression might play a role in the pathogenesis of leukaemic change. The clinical course of FL-LP could be aggressive, but a significant proportion of the patients obtained complete remission with chemotherapy.

[Factors associated with sleep quality during first and second trimester in Chinese pregnant woman]

Objective: To investigate sleep quality in pregnant women during their first and second trimester and to identify risk factors. Methods: Data was from the Chinese Pregnant Women Cohort Study. A total of 3 618 pregnant women were included, with the exclusion 346 women who had missing information. Sociodemographic, health-related behavior, depression and sleep quality information were collected and analyzed. Logistic regression analysis were used to explore the influencing factors of sleep quality in pregnant women. Results: Among the 3 618 pregnant woman 28.2% had poor sleep quality in their first trimester and 28.7% in the second trimester. 15.2% pregnant women had progressively worse sleep and 13.0% had persistently poor sleep had pregnant women were generally suffered from poor sleep quality, difficulty falling asleep, sleep disorders and daily fatigue. Regular diet (OR=0.75, 95%CI: 0.62-0.92) and work (OR=0.84,95%CI: 0.71-0.99) in the first trimester were protective factors of sleep quality in pregnant women. Age ≥30 year old (OR=1.19, 95%CI: 1.03-1.37), passive smoking (OR=1.18, 95%CI: 1.02-1.36) and depression (OR=2.25, 95%CI: 1.95-2.61) in the first trimester were risk factors. Conclusions: The rate of poor sleep quality are high among Chinese pregnant woman during their first and second trimester. The risk factors of sleep quality are multiple. Regular diet and work, reduction of tobacco exposure, alleviation of depression symptom may help improve sleep quality among pregnant women.

[Effect and mechanism of cardiac adipose triglyceride lipase overexpression on burn-induced cardiac injury]

Objective: To explore the effect and potential mechanism of cardiac adipose triglyceride lipase (ATGL) overexpression on burn-induced cardiac injury. Methods: Eight-week-old C57BL/6J mice with cardiac ATGL overexpression driven by the myosin heavy chain (MHC) promoter (MHC-ATGL burn group) and wild-type (wild-type burn group) mice were randomly chose to the following experiments with burn injury after 24 h (n=8/group), MHC-ATGL mice and wild-type mice with corresponded age and sex were included as control. Cardiac ATGL protein expression, serum levels of cardiac troponin T and cardiac kinase-MB (CK-MB), cardiac free fatty acid and reactive oxygen species were detected. The wild-type and MHC-ATGL burn groups were not only compared with their corresponded control groups, but also compared between each other. Results: The hair color and development were shown little difference between each group. ATGL protein expression is elevated in wild-type burn group (1.00±0.68 vs 3.09±0.93, P=0.023) and decreased in MHC-ATGL burn group (17.84±2.41 vs 10.36±2.22, P<0.001), while ATGL protein expression is still increased in MHC-ATGL burn group compared with wild-type burn group (P<0.001). Serum levels of cardiac troponin T and CK-MB were both elevated in wild-type burn group and MHC-ATGL burn group [(0.456±0.131) vs (0.076±0.019) μg/L and (0.219±0.089) vs (0.060±0.019) μg/L, (1 421±162) vs (221±67) U/L and (761±142) vs (221±41) U/L] (all P<0.001), while serum levels of cardiac troponin T and CK-MB was still decreased in MHC-ATGL burn group compared with wild-type burn group (P<0.001). In addition, cardiac free fatty acid was increased in wild-type burn group and little difference was found in MHC-ATGL burn group [(2.54±0.51) vs (0.46±0.27) mmol/L, P<0.001, and (0.81±0.38) vs (0.59±0.25) mmol/L, P=0.251], while cardiac free fatty acid was significant reduction in MHC-ATGL burn group compared with wild-type burn group (P<0.001). Levels of cardiac reactive oxygen species was both elevated in wild-type burn group and MHC-ATGL burn group [(1.89±0.23) vs (1.00±0.18) and (1.38±0.17) vs (0.95±0.13)] (both P<0.001), while levels of cardiac reactive oxygen was reduction in MHC-ATGL burn group compared with wild-type burn group (P<0.001). Conclusion: Cardiac ATGL overexpression may protect against burn-induced cardiac injury through reducing free fatty acid and reactive oxygen species production.

[Effects of sodium butyrate on intestinal barrier of severe scald mice and the related mechanism]

Objective: To investigate the effects of sodium butyrate on intestinal barrier of the severe scald mice and the related mechanism. Methods: Eighteen C57BL/6 female mice, aged eight to twelve weeks, were divided into sham scald group, pure scald group, and scald+ sodium butyrate group according to random number table, with 6 mice in each group. Back of each mouse in pure scald group and scald+ sodium butyrate group were immersed into 90 ℃ water for 9 s, causing full-thickness scald of 30% total body surface area, while back of each mouse in sham scald group were immersed into 37 ℃ water for 9 s, causing sham injury. All of the mice in 3 groups were intraperitoneally injected with 1 mL sterile lactated Ringer's solution immediately after injury. Besides, mice in scald+ sodium butyrate group were intraperitoneally injected with 300 mg/kg sodium butyrate at 30 min before injury and immediately after injury, while mice in sham scald group and pure scald group were intraperitoneally injected with the same volume of sterile phosphate buffer solution. At post injury hour (PIH) 24, portal vein of mice in 3 groups was harvested, intestinal permeability was measured by fluorescin isothiocyanate-dextran fluorescence probe tracing method, then lileal tissue of mice in 3 groups was harvested, protein expressions of zonula occludens l (ZO-1), occludin, claudin-1, claudin-2, nucleotide-binding oligomerization domain-containing protein-like receptor family pyrin domain containing 3 (NLRP3), interleukin-1β (IL-1β), and IL-18 were detected by Western blotting, and distribution of ZO-1 in intestinal mucosa was observed by indirect immunofluorescence. Data were processed with one-way analysis of variance, least-significant difference test, and Bonferroni correction. Results: (1) At PIH 24, the intestinal permeability of mice in sham scald group, pure scald group, and scald+ sodium butyrate group was 0.88±0.19, 2.62±0.48, 1.23±0.16, respectively. Compared with that in sham scald group, the intestinal permeability of mice in pure scald group was significantly elevated (P<0.01), while the intestinal permeability of mice in scald+ sodium butyrate group showed no obvious change (P>0.05). Compared with that in pure scald group, the intestinal permeability of mice in scald+ sodium butyrate group was significantly decreased (P<0.01). (2) At PIH 24, compared with those in sham scald group, the protein expressions of ZO-1, occludin, and claudin-1 of mice in pure scald group and scald+ sodium butyrate group were significantly decreased (P<0.05), while the protein expression of claudin-2 was significantly increased (P<0.05). At PIH 24, compared with those of pure scald group, the protein expressions of ZO-1 and occludin of mice in scald+ sodium butyrate group were significantly elevated (P<0.05), while the protein expression of claudin-2 was significantly decreased (P<0.05), the protein expression of claudin-1 showed no significant difference (P>0.05). (3) At PIH 24, compared with those in sham scald group, the protein expressions of NLRP3, IL-1β, and IL-18 of mice in pure scald group and scald+ sodium butyrate group were significantly increased (P<0.05). Compared with those of pure scald group, the protein expressions of NLRP3, IL-1β, and IL-18 of mice in scald+ sodium butyrate group were significantly decreased (P<0.05). (4) At PIH 24, ZO-1 in intestinal mucosa of mice in sham scald group was distributed smoothly, continuously and homogeneously along the membrane. ZO-1 in intestinal mucosa of mice in pure scald group was distributed unsmoothly with breaks. The distribution of ZO-1 in intestinal mucosa of mice in scald+ sodium butyrate group was ameliorated compared with that in pure scald group. Conclusions: Sodium butyrate can inhibit the activation of NLRP3 inflammasome and decrease the production of IL-1β and IL-18 in intestinal mucosa of severe scald mice, which protects the intestinal barrier function by alleviating the alteration of tight junction protein expression and localization.

[Risk factors for preterm birth, low birth weight and small for gestational age: a prospective cohort study]

Objective: To study the relationship between exposure factors in early pregnancy and preterm birth (PB), low birth weight (LBW) and small for gestational age (SGA) of neonates. Methods: A total of 3 172 pregnant women who were enrolled in the project of Chinese Pregnant Women Cohort Study-Peking Union Medical College (CPWCS-PUMC) from July 25, 2017 to July 24, 2018 and delivered before December 31, 2018 were selected as subjects in this study. The relationship between exposure factors in early pregnancy and adverse outcomes of neonatal delivery was analyzed by using binary logistic regression analysis. Results: The incidence rates of PB, LBW and SGA were 4.76%, 3.53% and 5.74%, respectively. In terms of PB, the analysis results showed that the gestational weight gain (GWG) and living in northern China were protective factors, while premature rupture of membranes, gestational hypertension, dental examination or treatment within 1-3 years and family with 3-4 members were risk factors. In the respect of LBW, GWG and daily consumption of milk and dairy products were the protective factors, while premature rupture of membranes, gestational hypertension, sedentary working time more than 6 hours, dental examination or treatment within 1-3 years and passive smoking were risk factors. For SGA, baby girl, passive smoking, peanut oil consumption and unsalted taste were risk factors, while folic acid supplementation was protective factor. Conclusion: The risk factors for PB, LBW and SGA were multifactorial, and relevant specific measures should be taken to reduce the occurrence of adverse neonatal outcomes.

P1569The Impact of Multidisciplinary Cardio-Oncology Program on the Cardiovascular Outcomes in Breast Cancer Patients

Background

Chemo- and target therapies may induce myocardial dysfunction and lead to poor prognoses. Early detection of minor myocardial dysfunction is important for the prevention of subsequent cardiotoxicity. Cardio-oncology is a multidisciplinary field focusing on managing and preventing cardiovascular complications in cancer patients. However, whether Cardio-oncology program truly makes difference in cardiovascular outcomes remains unknown. Herein, we are sharing our experiences in our Medical Center.

Methods

Since 2014 till 2017, we recruited 154 patients with newly diagnosed breast cancer preparing for Epirubicin therapy. Echocardiography, biomarkers, six minute walking distance and cardiovascular adverse events including new onset of hypertension, stroke, myocardial infarction (MI) and mortality were recorded at baseline, three months, six months and one year. Any functional decline was reported to oncologists for the consideration of changing regimens. Otherwise, cardiologists would be consulted for cardiovascular educations and therapies. The echocardiographic and clinical records of 450 breast patients receiving Epirubicin therapy during 2010 to 2013 were also collected as comparison.

Results

Compared with the ratio of 20% patients receiving echocardiography prior to 2014, the ratio increased to 100% since Cardio-Oncology program started. Also, the drop of left ventricular ejection fraction (LVEF) from 25% attenuated to 5%. Before Cardio-Oncology Program, there were 1.7% of new onset hypertension, 0.8% of MI, 0.8% of stroke and 16.8% of mortality. Conversely, after the program, there were only 0.6% of new onset hypertension while no other cardiovascular complications were reported. Furthermore, compared with previous reports of the effectiveness of Cardio-Oncology Program, our result also displayed a superior impact on the cardiovascular outcomes.

Conclusions

Collectively, through a comprehensive monitoring and an early intervention of myocardial dysfunction post chemotherapies, Cardio-Oncology Program truly decreased the cardiovascular complications in breast cancer patients.

Acknowledgement/Funding

Chi-Mei Medical Center

[Effects of short chain fatty acid on barrier disruption of human intestinal epithelial cell induced by endotoxin/lipopolysaccharide and the related mechanism]

Objective: To investigate the effects of short chain fatty acid (SCFA) on barrier disruption of human intestinal epithelial cell induced by endotoxin/lipopolysaccharide (LPS) and the related mechanism. Methods: The human intestinal epithelial cell line Caco-2 was used to reproduce monolayer-cells. Cells were divided into control group, LPS group, and SCFA+ LPS group according to the random number table. Cells in control group were only routinely cultured with DMEM medium. Cells in LPS group were cultured with DMEM medium and LPS with final mass concentration of 10 μg/mL. Cells in SCFA+ LPS group were cultured with DMEM medium, LPS and SCFA (consisting of 0.5 mmol/L acetate, 0.01 mmol/L propionate, and 0.01 mmol/L butyrate) with final mass concentration of 10 μg/mL. At post culture hour (PCH) 0, 1, 2, 6, 12, and 24, transepithelial electrical resistance (TER) of cells was determined with an ohmmeter, with sample number of 72. Another portion of cells were divided and treated as above, and then Western blotting was employed to detect the protein expressions of zonula occludens 1 (ZO-1), occludin, and claudin-1 at PCH 24, with sample number of 6. Another portion of cells were divided and treated as above and then immunofluorescence was used to observe cellular morphology and distribution of ZO-1. Data were processed with analysis of variance of factorial design, one-way analysis of variance, least-significant difference test, and Bonferroni correction. Results: (1) Compared with that in control group, TER of cells in LPS group was significantly reduced from PCH 1 to 24 (P<0.01), while TER of cells in SCFA+ LPS group showed no obvious change (P>0.05). TER of cells in SCFA+ LPS group was significantly higher than that in LPS group from PCH 1 to 24 (P<0.01). (2) Compared with the protein expressions of ZO-1, occludin, and claudin-1 of cells in control group (1.25±0.10, 1.17±0.04, and 1.24±0.20), those of cells in LPS group (0.74±0.23, 0.76±0.11, and 0.77±0.11) at PCH 24 were significantly decreased (P<0.05), while those of cells in SCFA+ LPS group (1.23±0.46, 1.05±0.09, and 1.01±0.13) showed no significant differences (P>0.05). Protein expressions of occludin and claudin-1 of cells in SCFA+ LPS group were significantly higher than those in LPS group at PCH 24 (P<0.05). Protein expression of ZO-1 of cells in SCFA+ LPS group was higher than that in LPS group at PCH 24 with no significant difference (P>0.05). (3) At PCH 24, cells in control group were compact in arrangement with pebble-like appearance, and ZO-1 was distributed smoothly and continuously along the cell membrane. In LPS group, cells were sparse in arrangement with change in appearance, and ZO-1 was distributed uncontinuously along the cell membrane with curls and breaks. In SCFA+ LPS group, the appearance of cells and distribution of ZO-1 were remarkably ameliorated compared with those in LPS group. Conclusions: SCFA can alleviate the barrier disruption of human intestinal epithelial cell induced by LPS through interdicting the abnormal distribution of ZO-1 and decrease of TER and tight junction proteins' expressions.

Cloning of three genes involved in the flavonoid metabolic pathway and their expression during insect resistance in Pinus massoniana Lamb

Pinus massoniana Lamb. is an important timber and turpentine-producing tree species in China. Dendrolimus punctatus and Dasychira axutha are leaf-eating pests that have harmful effects on P. massoniana production. Few studies have focused on the molecular mechanisms underlying pest resistance in P. massoniana. Based on sequencing analysis of the transcriptomes of insect-resistant P. massoniana, three key genes involved in the flavonoid metabolic pathway were identified in the present study (PmF3H, PmF3'5'H, and PmC4H). Structural domain analysis showed that the PmF3H gene contains typical binding sites for the 2OG-Fe (II) oxygenase superfamily, while PmF3'5'H and PmC4H both contain the cytochrome P450 structural domain, which is specific for P450 enzymes. Phylogenetic analysis showed that each of the three P. massoniana genes, and the homologous genes in gymnosperms, clustered into a group. Expression of these three genes was highest in the stems, and was higher in the insect-resistant P. massoniana varieties than in the controls. The extent of the increased expression in the insect-resistant P. massoniana varieties indicated that these three genes are involved in defense mechanisms against pests in this species. In the insect-resistant varieties, rapid induction of PmF3H increased the levels of PmF3'5'H and PmC4H expression. The enhanced anti-pest capability of the insect-resistant varieties could be related to temperature and humidity. In addition, these results suggest that these three genes maycontribute to the change in flower color during female cone development.

[Study on correlation between retinal vessel morphology or ocular hemodynamic parameter and internal carotid artery stenosis]

Objective: To analyze the correlation between retinal vascular calibers, ocular blood flow parameters and internal carotid artery stenosis and to evaluate the effect of internal carotid artery stenosis on ocular blood vessels comprehensively. Methods: A retrospective case-control study. The clinical data of 141 patients who underwent head-and-neck computed tomography (CT) angiography examinations of the ICA were collected at Beijing Friendship Hospital, Capital Medical University from January 2014 to January 2016. According to diagnostic criteria, the patients were divided into four groups: the non-stenosis group, the mild stenosis group, the moderate stenosis group, and the severe stenosis andocclusion group. The retinal vascular caliber was measured in color fundus photograph by IVAN software. Color Doppler ultrasonography was used to measure the parameters of ocular blood flow, including the peak systolic velocity (PSV), end diastolic velocity (EDV), resistance index (RI) and pulsatility index (PI). The enumeration data were analyzed with chi-square test, the measurement data were analyzed with rank-sum test, and the correlation test was performed with spearman. Results: The gender ratio of the patients without stenosis, mild stenosis, moderate stenosis, severe stenosis and occlusion was 12/7, 31/19, 28/25, 12/7, χ² test was not statistically significant (χ²= 0.79, P=0.85); There was no statistically significant difference between the different groups (χ²= 0.15, P=0.68), the age of four groups were (64.1±8.3), (54.3±14.3), (68.9±11.8) and (59.1±8.0) y, respectively. In the no internal carotid artery stenosis group, the arteries diameter is (164.5±15.6) μm ,the vein diameter is (245.6±20.0) μm and the arteriovenous ratio is 0.7±0.1. There is no difference among the mild stenosis group, moderate stenosis group and the severe stenosis (χ²_{artery calibe}r=6.92, P_{artery calibe}r=0.08; χ²_{vein diamete}r=4.16, P_{vein diamete}r=0.25; χ²_{arteriolar-venular ratio}=1.38,P_{arteriolar-venular ratio}=0.71) . The PSV of central retinal artery in the above groups were (14.6±3.6), (34.4±13.2), (35.7±14.6), (42.3±19.0)cm/s respectively, the data were analyzed by rank-sum test and there was a significant difference (χ²=13.44, P< 0.01) ; The PSV of the posterior ciliary artery in the above groups (17.6±6.5), (15.0±4.6), (13.4±4.3) and (11.0±3.2)cm/s respectively, the data were analyzed by rank-sum test and there was a significant difference (χ²=22.71, P<0.01) , EDV were (5.90±2.2), (5.1±2.1), (4.3±1.5) and (4.3±4.8)cm/s respectively and there was a significant difference (χ²=20.36, P<0.01) .There was a correlation between retinal artery diameter, PSV and EDV of the central retinal artery, PSV and EDV of the posterior ciliary artery and the diameter of the internal carotid artery but without linear correlation. (r_{artery calibe}r=-0.23, P_{artery calibe}r=0.01; r_{PSV of central retinal artery}= -0.29, P_{PSV of central retinal artery}<0.01; r_{PSV of posteri or ciliary artery}=-0.34, P_{PSV of posterior ciliary artery}<0.01, r_{EDV of posterior ciliary artery}=-0.35, P_{EDV of posterior ciliary artery}<0.01). Conclusions: There was a correlation between retinal artery diameter, PSV and EDV of the central retinal artery, PSV and EDV of the posterior ciliary artery and the diameter of the internal carotid artery. PSV of the central retinal artery, PSV and EDV of the posterior ciliary artery changed significantly when the internal carotid artery stenosis existed. (Chin J Ophthalmol, 2016, 52: 905-910).

Development and characterization of SSR markers from Pinus massoniana and their transferability to P. elliottii, P. caribaea and P. yunnanensis

Pinus massoniana (Masson's pine) is a widespread tree species in central and southern China and northern Vietnam; it is valued for rosin and paper production. Despite the significant economic value of Masson's pine, little work has been done on its molecular genetics. We developed 318 SSR primers from genome sequences of P. massoniana, and we identified 10 polymorphic markers. The number of alleles in the population of P. massoniana that we examined ranged from two to four, and the Shannon diversity index ranged from 0.150 to 1.133. Cross-species transferability of the 318 SSRs was also analyzed in the slash pine (Pinus elliottii), the Caribbean pine (Pinus caribaea) and the Yunnan pine (Pinus yunnanensis); 15, 10, and 10 primer pairs generated polymorphic amplification, respectively. These sets of polymorphic SSR markers will be useful for population genetics studies of P. massoniana, for genetic identification of interspecific hybridization, and for phylogeographic studies of Pinus spp.

Full-term pregnant women have higher lumbar epidural pressure than non-pregnant women: a preliminary report

The objective of this study was to compare the lumbar epidural pressure of full-term pregnant women with that of non-pregnant women. The epidural pressure of 20 full-term pregnant women and 15 non-pregnant women was measured during epidural needle insertion in the lateral position (T0), and at 30-s intervals following insertion (T1-T3), after the patient was turned supine (T4-T6), and after local anaesthetic injection (T7-T9). Results showed that the average epidural pressures following epidural insertion in the lateral position (average of T1-T3), in the supine position (average of T4-T6), and after local anaesthetic injection (average of T7-T9) were all significantly higher in the pregnant women compared with those who were not pregnant (p= 0.0293, 0.0109 and 0.0309, respectively). Epidural pressures increased significantly after women were turned supine (p < 0.001). Average epidural pressures were positive for all time points, T0-T9. It was concluded that the epidural pressure in the pregnant women was higher than in those who were not pregnant, both in the lateral and the supine position.

Endogenously expressed truncated P2X7 receptor lacking the C-terminus is preferentially upregulated in epithelial cancer cells and fails to mediate ligand-induced pore formation and apoptosis

A truncated naturally occurring variant of the human purinergic receptor P2X7 (P2X7-R) was found in human cancer cervical cells. The novel protein consists of 258 amino acids, and compared to the wild-type P2X7-R it lacks the entire intracellular carboxy terminus, the second transmembrane domain, and the distal third of the extracellular loop. The truncated P2X7-R failed to form pores and mediate apoptosis, and it interacted with the wild-type P2X7-R in a manner suggesting auto-hetero-oligomerization. In contrast to cancer cells the novel truncated P2X7-R was expressed relatively little in normal cervical cells. These data raise the possibility that coexpression of the truncated form could block P2X7 mediated apoptosis and promote uncontrolled growth of cells.

Reversible inactivation of AT(2) angiotensin II receptor from cysteine-disulfide bond exchange

Dithiothreitol (DTT) treatment of angiotensin II (Ang II) type 2 (AT(2)) receptor potentiates ligand binding, but the underlying mechanism is not known. Two disulfide bonds proposed in the extracellular domain were examined in this report. Based on the analysis of ligand affinity of cysteine (Cys, C) to alanine (Ala, A) substitution mutants, we provide evidence that Cys(35)-Cys(290) and Cys(117)-Cys(195) disulfide bonds are formed in the wild-type AT(2) receptor. Disruption of the highly conserved Cys(117)-Cys(195) disulfide bond linking the second and third extracellular segments leads to inactivation of the receptor. The Cys(35)-Cys(290) bond is highly sensitive to DTT. Its breakage results in an increased binding affinity for both Ang II and the AT(2) receptor-specific antagonist PD123319. Surprisingly, in the single Cys mutants, C35A and C290A, a labile population of receptors is produced which can be re-folded to high-affinity state by DTT treatment. These results suggest that the free -SH group of Cys(35) or Cys(290) competes with the disulfide bond formation between Cys(117) and Cys(195). This Cys-disulfide bond exchange results in production of the inactive population of the mutant receptors through formation of a non-native disulfide bond.

[Protective effects of SMT on myocardial ultrastructure of ischemia reperfusion injury in heart of rat]

AIM

To Investigate the myocardial ultrastructure effects of SMT on the ischemia reperfusion injury (IRI) in the rat heart.

METHODS

Eighteen Spraqua-Dawley rats were randomly divided into three groups: ischemia reperfusion group (IR), subjected to 60 min of o-cclusion and 20 min of reperfusion of the anterior descending branch of left coronary artery; IR + SMT group (SMT), given the selective iNOS inhibitor S-methylisothiourea sulfate (SMT, 5 mg/kg, i.v.) before reperfusion; control group (C), didn't occlude coronary artery after exposing heart and observed 80 min. Electrocardiogram (ECG) was recorded. Nitrite and nitrate content were measured in myocardium and blood serum. The changes of myocardial ultrastructure were observed with electron microscope.

RESULTS

Ischemia reperfusion induced ST segment elevation and T waves inversion or tallness in ECG, damaged myocardial ultrastructure, increased nitrite and nitrate content in myocardium and blood serum after IR compared with before IR(P < 0.01). Administration of SMT improved the changes of ECG and the injury of myocardial ultrastructure. Nitrite and nitrate content of myocardium were lower than IR group (P < 0.05). The change of nitrite and nitrate level of blood serum in SMT group was nearly in C group.

CONCLUSION

SMT can prevent myocardium injury from reperfusion following ischemia.

[Effects on fiber regeneration following facial nerve transection treated with NOS antagonist]

OBJECTIVE

To elucidate the role of nitric oxide synthase antagonist, N-Nitro-L-Arginine Methyl Ester (L-NAME) in the regeneration of facial nerve following facial nerve transection.

METHOD

The facial nerves of 40 guinea pigs were exposed and a segment of the nerve at 3 mm length were excided. The two ends of the transected nerve were sutured and enveloped in a silicone tubule to form a regeneration chamber. L-NAME and saline were respectively injected into the regeneration chambers just after transection. The experiments were observed quantificational by the means of axon and myelin staining under light microscope.

RESULT

The findings in the work indicate that inhibition of NOS with L-NAME substantially better myelinated facial nerve regeneration than that associated with administration of saline.

CONCLUSION

L-NAME improve the regeneration of myelinated fibers. The mechanism seems to be related to the blockade of NO's neurotoxicity.

Role of transmembrane helix IV in G-protein specificity of the angiotensin II type 1 receptor

G-protein activation by G-protein coupled receptors (GPCRs) is accomplished through proper interaction with the cytoplasmic loops rather than through sequence-specific interactions. However, the mechanism by which a specific G-protein is selected by a GPCR is not known. In the current model of GPCR activation, agonist binding modulates helix-helix interactions, which is necessary for fully determining G-protein specificity and stimulation of GDP/GTP exchange. In this study, we report that a single-residue deletion in transmembrane helix IV leads the angiotensin II type 1 (AT(1)) receptor chimera CR17 to retain GTP-sensitive high affinity for the agonist angiotensin II but results in complete inactivation of intracellular inositol phosphate production. The agonist dissociation profile of CR17 in the presence of guanosine 5'-3-O-(thio)triphosphate suggests that the activation-induced conformational changes of the chimeric receptor itself remain intact. Insertion of an alanine at position 149 (CR17triangle down149A) in this chimera rescued the inactive phenotype, restoring intracellular inositol phosphate production by the chimera. This finding suggests that in the wild-type AT(1) receptor the orientation of transmembrane helix IV-residues following Cys(149) is a key determinant for effectively distinguishing among various structurally similar G-proteins. The results emphasize that the contacts within the membrane-embedded portion of transmembrane helix IV in the AT(1) receptor is important for specific G-protein selection.

Role of aromaticity of agonist switches of angiotensin II in the activation of the AT1 receptor

We have shown previously that the octapeptide angiotensin II (Ang II) activates the AT1 receptor through an induced-fit mechanism (Noda, K., Feng, Y. H., Liu, X. P., Saad, Y., Husain, A., and Karnik, S. S. (1996) Biochemistry 35, 16435-16442). In this activation process, interactions between Tyr4 and Phe8 of Ang II with Asn111 and His256 of the AT1 receptor, respectively, are essential for agonism. Here we show that aromaticity, primarily, and size, secondarily, of the Tyr4 side chain are important in activating the receptor. Activation analysis of AT1 receptor position 111 mutants by various Ang II position 4 analogues suggests that an amino-aromatic bonding interaction operates between the residue Asn111 of the AT1 receptor and Tyr4 of Ang II. Degree and potency of AT1 receptor activation by Ang II can be recreated by a reciprocal exchange of aromatic and amide groups between positions 4 and 111 of Ang II and the AT1 receptor, respectively. In several other bonding combinations, set up between Ang II position 4 analogues and receptor mutants, the gain of affinity is not accompanied by gain of function. Activation analysis of position 256 receptor mutants by Ang II position 8 analogues suggests that aromaticity of Phe8 and His256 side chains is crucial for receptor activation; however, a stacked rather than an amino-aromatic interaction appears to operate at this switch locus. Interaction between these residues, unlike the Tyr4:Asn111 interaction, plays an insignificant role in ligand docking.

The active state of the AT1 angiotensin receptor is generated by angiotensin II induction

In the current model of receptor activation, the given hormone is not involved in the conversion of the inactive receptor (R) to the fully active state (R*). Rather, it preferentially selects the activated receptor conformation, thereby shifting the equilibrium toward R*. The hormone angiotensin II (Ang II) contains two residues, Tyr4 and Phe8, that are essential for agonism. We show that the conserved Asn111 in transmembrane helix III of the AT1 angiotensin receptor directly interacts with the Tyr4 side chain. A decrease in the size of the Asn111 side chain induces an intermediate activated receptor conformation (R'). The Ang II analogue [Sar1,Ile4,Ile8]Ang II fully activates the N111G mutant, indicating that either the transition from R' to R* or the stabilization of the R* state requires binding by Ang II but not its Tyr4 and Phe8 side chains. In contrast, [Sar1,Ile4,Ile8]Ang II binds to but does not activate the wild-type AT1 receptor (R), suggesting that in the wild-type receptor spontaneous occurrence of R' and R* states is rare. Thus, Ang II through interactions involving Tyr4 and Phe8 induces a transition from R to R' and through unspecified interactions induces transition from R' to R* states rather than stabilizing the spontaneously generated R* state by "conformational, selection".

Suppression of oxidant production by diltiazem, nifedipine and verapamil in human neutrophils

1. Polymorphonuclear leucocytes are a major source of toxic oxidants in vivo, causing tissue injury in certain circumstances such as ischaemia and reperfusion. Calcium ions are a key mediator in the production of oxidants by these cells. The aim of this study was to examine the effects of the widely used calcium antagonists diltiazem, nifedipine and verapamil on the production of oxidants in neutrophils. 2. Human neutrophils were freshly prepared, suspended in different luminol media and mixed with varying amounts of each calcium antagonist. They were then stimulated with either serum-opsonized zymosan or phorbol 12-myristate 13-acetate. Oxidant production was determined by three methods, namely luminol-enhanced chemiluminescence, oxygen consumption and cytochemical staining. 3. Calcium antagonists inhibited oxidant production by neutrophils. IC50 values for diltiazem, nifedipine and verapamil in calcium-free medium were 0.32 mmol/l (SEM 0.02), 0.27 mmol/l (SEM 0.02) and 0.24 mmol/l (SEM 0.02) respectively under zymosan stimulation, and 0.33 mmol/l (SEM 0.02), 0.26 mmol/l (SEM 0.02) and 0.13 mmol/l (SEM 0.07) respectively under phorbol 12-myristate 13-acetate stimulation. These effects were independent of the presence of Ca2+ in the extracellular solution. Some inhibition was also observed when the calcium antagonists were added during the course of a respiratory burst. Oxygen uptake by the cells was reduced in the presence of each calcium antagonist. Phagocytosis by the stimulated neutrophils was not affected despite inhibition of oxidant production. 4. We conclude that calcium antagonists can suppress the capacity of neutrophils to produce oxidants. This result may provide a novel explanation for the observation that delayed treatment with calcium antagonists may attenuate post-ischaemic myocardial dysfunction.

In vitro oxidative damage to tissue-type plasminogen activator: a selective modification of the biological functions

OBJECTIVE

Tissue-type plasminogen activator (t-PA) is an important component of the blood fibrinolytic system responsible for thrombus dissolution. It is often required to function under oxidative stress, and exogenous t-PA is used clinically in the treatment of acute myocardial infarction (AMI). The aim of this study was to examine alterations in the residual activity of t-PA pre-treated with certain oxidants.

METHODS

Recombinant t-PA (rt-PA) and native t-PA (nt-PA) were pre-treated with freshly generated hypochlorous acid (HOCl) and chloramine T at varying concentrations. The amidolytic activity, the plasminogenolytic activity and the fibrin-binding affinity were then examined using chromogenic assays based on S-2288 and S-2251.

RESULTS

The amidolytic activity of t-PA was surprisingly found to be rather sensitive (IC50 1 and 12 mumol/1, respectively), and the plasminogenolytic activity rather resistant to pre-treatment with HOCl and chloramine T. The fibrin binding study of treated t-PA revealed substantial loss of binding to CNBr-digested fibrinogen (FDP-CNBr). The velocity of t-PA in reaction with plasminogen remained the same as non-treated t-PA. The possible mechanisms of this asymmetrical oxidative modification of the biological functions are also discussed.

CONCLUSIONS

(1) The catalytic activity of t-PA and the binding affinity for its large-molecule substrate plasminogen, rather than the small-molecule substrate S-2288, are highly resistant to oxidative damage; (2) the fibrin-binding affinity of t-PA can be selectively and asymmetrically damaged by exposure to these oxidants. Thus it is possible that the characteristic advantage of thrombus selectivity of t-PA in both spontaneous thrombolysis and thrombolytic therapy may be diluted in circumstances where toxic and reactive oxidants exist.

The docking of Arg2 of angiotensin II with Asp281 of AT1 receptor is essential for full agonism

The structural model of AT1 angiotensin receptor contains seven-transmembrane alpha-helices with three interhelical loops on either side of the membrane. The angiotensin II binding pocket within the receptor is not clearly defined. We showed earlier that Lys199 in transmembrane-helix-5 of the AT1 receptor binds the COOH-terminal alpha-carboxyl group of angiotensin II (Noda, K., Saad, Y., Kinoshita, A., Boyle, T. P., Graham, R. M., Husain, A., and Karnik, S. S. (1995) J. Biol. Chem. 270, 2284-2289). We now show that His183 and Asp281, both located in the extracellular domain of the AT1 receptor, are involved in binding the NH2-terminal Asp1 and Arg2 residues of angiotensin II, respectively. The Asp1/His183 interaction appears to be weak and is unlikely to be important for agonism. But the loss of Arg2/Asp281 interaction leads to partial agonism of the receptor. The action of non-peptide agonists is not affected by Asp281 mutations. These results suggest that several independent interactions between angiotensin II and AT1 receptor are necessary for full agonism. Since L-162,313 the non-peptide agonist of the AT1 receptor is a partial agonist that does not make contact with Asp281, we speculate that the degree of agonism may be increased if it is redesigned to make contacts with Asp281.

Persistent peripheral vasodilation and sympathetic activity in hypotension after maximal exercise

Hemodynamics (by aortic Doppler), autonomic factors (power spectrum analysis of heart rate and blood pressure variabilities and baroreceptor sensitivity), and plasma renin activity during the hypotension after maximal exercise were studied in 10 normal subjects on two separate days: a nonexercise (control) day (30 min of upright rest followed by 60 min of supine rest) and an exercise day (maximal upright bicycle exercise followed by 60 min supine) in random order. After exercise, diastolic pressure was reduced for the entire hour, cardiac output increased (+33.8%, P < 0.05), stroke volume was unchanged, and systemic vascular resistance fell (-28.6%, P < 0.01). Indexes of vagal activity were reduced for 60 min, whereas the sympathetic indexes were elevated. Baroreflex sensitivity was also reduced for the first 10 min after exercise. Renin activity increased threefold after exercise. The postexercise hypotension results from a persisting peripheral vasodilation despite an increase in renin activity: the persistent sympathetic activity and reduced vagal tone are probably reflex responses to this vasodilatation.