Pyruvate kinase activators: targeting red cell metabolism in sickle cell disease

Hemoglobin S (HbS) polymerization, red blood cell (RBC) sickling, chronic anemia, and vaso-occlusion are core to sickle cell disease (SCD) pathophysiology. Pyruvate kinase (PK) activators are a novel class of drugs that target RBC metabolism by reducing the buildup of the glycolytic intermediate 2,3-diphosphoglycerate (2,3-DPG) and increasing production of adenosine triphosphate (ATP). Lower 2,3-DPG level is associated with an increase in oxygen affinity and reduction in HbS polymerization, while increased RBC ATP may improve RBC membrane integrity and survival. There are currently 3 PK activators in clinical development for SCD: mitapivat (AG-348), etavopivat (FT-4202), and the second-generation molecule AG-946. Preclinical and clinical data from these 3 molecules demonstrate the ability of PK activators to lower 2,3-DPG levels and increase ATP levels in animal models and patients with SCD, as well as influence a number of potential pathways in SCD, including hemoglobin oxygen affinity, RBC sickling, RBC deformability, RBC hydration, inflammation, oxidative stress, hypercoagulability, and adhesion. Furthermore, early-phase clinical trials of mitapivat and etavopivat have demonstrated the safety and tolerability of PK activators in patients with SCD, and phase 2/3 trials for both drugs are ongoing. Additional considerations for this novel therapeutic approach include the balance between increasing hemoglobin oxygen affinity and tissue oxygen delivery, the cost and accessibility of these drugs, and the potential of multimodal therapy with existing and novel therapies targeting different disease mechanisms in SCD.

Fatty acid nitroalkenes - Multi-target agents for the treatment of sickle cell disease

Sickle cell disease (SCD) is a hereditary hematological disease with high morbidity and mortality rates worldwide. Despite being monogenic, SCD patients display a plethora of disease-associated complications including anemia, oxidative stress, sterile inflammation, vaso-occlusive crisis-related pain, and vasculopathy, all of which contribute to multiorgan dysfunction and failure. Over the past decade, numerous small molecule drugs, biologics, and gene-based interventions have been evaluated; however, only four disease-modifying drug therapies are presently FDA approved. Barriers regarding effectiveness, accessibility, affordability, tolerance, and compliance of the current polypharmacy-based disease-management approaches are challenging. As such, there is an unmet pharmacological need for safer, more efficacious, and logistically accessible treatment options for SCD patients. Herein, we evaluate the potential of small molecule nitroalkenes such as nitro-fatty acid (NO2-FA) as a therapy for SCD. These agents are electrophilic and exert anti-inflammatory and tissue repair effects through an ability to transiently post-translationally bind to and modify transcription factors, pro-inflammatory enzymes and cell signaling mediators. Preclinical and clinical studies affirm safety of the drug class and a murine model of SCD reveals protection against inflammation, fibrosis, and vascular dysfunction. Despite protective cardiac, renal, pulmonary, and central nervous system effects of nitroalkenes, they have not previously been considered as therapy for SCD. We highlight the pathways targeted by this drug class, which can potentially prevent the end-organ damage associated with SCD and contrast their prospective therapeutic benefits for SCD as opposed to current polypharmacy approaches.

[Clinicopathological and gene mutation characteristics of uterine carcinosarcoma]

To explore the clinicopathological characteristics, immunophenotype, diagnosis and differential diagnosis of uterine carcinosarcoma (UCS), and to explore the gene mutation characteristics and tumor mutation burden (TMB) of UCS. The clinical imaging, pathomorphological data and immunohistochemical expression of 4 cases of UCS, which were archived in the Department of Pathology of the Second Affiliated Hospital of Soochow University from January 2021 to May 2022 were retrospectively analyzed. All exon groups of 4 cases of UCS were sequenced. All the 4 patients were female, aged 47-81 years. The maximum diameter of the tumor was 4.0-13.0 cm, and the boundary was unclear. Microscopically, the tumor was composed of malignant epithelium and sarcoma. Immunohistochemistry showed that the epithelial components of 4 patients expressed broad-spectrum cytokeratin (AE1/E3), the sarcoma components expressed Vimentin, PAX8, ER, PR were expressed to varying degrees, and Ki-67 positive index was high (60%-90%). There were 3 p53 missense mutations, 1 nonsense mutation, 4 MLH1, PMS2, MSH2, MSH6 were positive and PD-L1 was negative. The sequencing results of the whole exon group of 4 UCS patients showed that TP53, BCL9L, BRD4, CLTCLI, PSMD1I, PLEC genes showed a high mutation ratio, which was 3/4, 2/4, 2/4, 2/4, 2/4, 2/4, respectively. TMB analysis showed that the TMB of 4 cases of UCS was<5 mut/Mb. UCS is a rare and highly malignant endometrial tumor. The sequencing results of the whole exon group suggested that TP53, BCL9L, BRD4 and other genes had high mutation rates, suggesting that the occurrence and development of UCS may be closely related to Wnt signaling pathway. Molecular typing indicated that 3 cases of UCS were of high copy number type/p53 mutation type, and 1 case had POLD1 mutation. Microsatellite stability, low PD-L1 expression and TMB results suggested that UCS patients have no obvious advantage in immunotherapy.

Diagnostic Test Accuracy of Lung Ultrasound for Acute Chest Syndrome in Sickle Cell Disease: A Systematic Review and Meta-analysis

BACKGROUND

Acute chest syndrome (ACS) is a leading cause of death in patients with sickle cell disease. Lung ultrasound (LUS) is emerging as a point-of-care method to diagnose ACS, allowing for more rapid diagnosis in the ED setting and sparing patients from ionizing radiation exposure.

RESEARCH QUESTION

What is the diagnostic accuracy of LUS for ACS diagnosis, using the current reference standard of chest radiography?

STUDY DESIGN AND METHODS

Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed for this systematic review and meta-analysis. Embase, MEDLINE, Web of Science, and Google Scholar were used to compile all relevant studies. Two reviewers screened the studies for inclusion in this review. Cases of discrepancy were resolved by a third reviewer. Meta-analyses were conducted using both metadta and midas STATA software packages to retrieve summary receiver operating characteristic curves, sensitivities, and specificities. Three reviewers scored the studies with QUADAS-2 for risk of bias assessment.

RESULTS

From a total of 713 unique studies retrieved, six studies were included in the final quantitative synthesis. Of these, five studies were in pediatric EDs. Two studies were conference abstracts and not published manuscripts. Data were available for 625 possible ACS cases (97% of cases in patients aged ≤ 21 years) and 95 confirmed ACS diagnoses (pretest probability of 15.2%). The summary sensitivity was 0.92 (95% CI, 0.68-0.98) and the summary specificity was 0.89 (95% CI, 0.69-0.97) with an area under the curve of the summary receiver operating characteristic curve of 0.96 (95% CI, 0.94-0.97).

INTERPRETATION

LUS has excellent sensitivity and very good specificity for ACS diagnosis and may serve as an initial point-of-care test to facilitate rapid treatment of ACS and spare pediatric patients from ionizing radiation; however, further research is warranted to improve the generalizability to the adult sickle cell disease population.

Release of hepatic xanthine oxidase (XO) to the circulation is protective in intravascular hemolytic crisis

Xanthine oxidase (XO) catalyzes the catabolism of hypoxanthine to xanthine and xanthine to uric acid, generating oxidants as a byproduct. Importantly, XO activity is elevated in numerous hemolytic conditions including sickle cell disease (SCD); however, the role of XO in this context has not been elucidated. Whereas long-standing dogma suggests elevated levels of XO in the vascular compartment contribute to vascular pathology via increased oxidant production, herein, we demonstrate, for the first time, that XO has an unexpected protective role during hemolysis. Using an established hemolysis model, we found that intravascular hemin challenge (40 μmol/kg) resulted in a significant increase in hemolysis and an immense (20-fold) elevation in plasma XO activity in Townes sickle cell phenotype (SS) sickle mice compared to controls. Repeating the hemin challenge model in hepatocyte-specific XO knockout mice transplanted with SS bone marrow confirmed the liver as the source of enhanced circulating XO as these mice demonstrated 100% lethality compared to 40% survival in controls. In addition, studies in murine hepatocytes (AML12) revealed hemin mediates upregulation and release of XO to the medium in a toll like receptor 4 (TLR4)-dependent manner. Furthermore, we demonstrate that XO degrades oxyhemoglobin and releases free hemin and iron in a hydrogen peroxide-dependent manner. Additional biochemical studies revealed purified XO binds free hemin to diminish the potential for deleterious hemin-related redox reactions as well as prevents platelet aggregation. In the aggregate, data herein reveals that intravascular hemin challenge induces XO release by hepatocytes through hemin-TLR4 signaling, resulting in an immense elevation of circulating XO. This increased XO activity in the vascular compartment mediates protection from intravascular hemin crisis by binding and potentially degrading hemin at the apical surface of the endothelium where XO is known to be bound and sequestered by endothelial glycosaminoglycans (GAGs).

Characteristics of atmospheric ice nucleating particles over East Antarctica retrieved from the surface snow

The concentration of ice nucleating particles (INPs) in the atmosphere is critical for understanding cloud microphysics and predicting the climate system. In this study, we collected surface snow samples along a traverse route from the coastal to the inland of East Antarctica to analyze INP concentration and identify its spatial variations using a droplet freezing device. The overall concentration of INPs was found to be considerably low along the route, averaging at 0.8 ± 0.8 × 10⁵ L^-1 in water and 4.2 ± 4.8 × 10^-3 L^-1 in air at -20 °C. Although coastal areas had higher levels of sea salt species compared to inland regions, the concentration of INPs remained consistent along the route suggesting less important origination of INPs from the around ocean. Additionally, the heating experiment revealed the important contribution of proteinaceous INPs indicating the presence of biological INPs (bio-INPs). The fraction of bio-INPs was 0.52 on average at -20 °C and ranged from 0.1 to 0.7 from -30 °C to -15 °C. Finally, we parameterize the atmospheric INP concentrations as a function of freezing temperature which can be useful for modeling INP concentrations in this region.

[Revision rate of periprosthetic joint infection post total hip or knee arthroplasty of 34 hospitals in China between 2015 and 2017: a multi-center survey]

Objective: To investigate the rate of periprosthetic joint infection (PJI) revision surgeries and clinical information of hip-/knee- PJI cases nationwide from 2015 to 2017 in China. Methods: An epidemiological investigation. A self-designed questionnaire and convenience sampling were used to survey 41 regional joint replacement centers nationwide from November 2018 to December 2019 in China. The PJI was diagnosed according to the Musculoskeletal Infection Association criteria. Data of PJI patients were obtained by searching the inpatient database of each hospital. Questionnaire entries were extracted from the clinical records by specialist. Then the differences in rate of PJI revision surgery between hip- and knee- PJI revision cases were calculated and compared. Results: Total of 36 hospitals (87.8%) nationwide reported data on 99 791 hip and knee arthroplasties performed from 2015 to 2017, with 946 revisions due to PJI (0.96%). The overall hip-PJI revision rate was 0.99% (481/48 574), and it was 0.97% (135/13 963), 0.97% (153/15 730) and 1.07% (193/17 881) in of 2015, 2016, 2017, respectively. The overall knee-PJI revision rate was 0.91% (465/51 271), and it was 0.90% (131/14 650), 0.88% (155/17 693) and 0.94% (179/18 982) in 2015, 2016, 2017, respectively. Heilongjiang (2.2%, 40/1 805), Fujian (2.2%, 45/2 017), Jiangsu (2.1%, 85/3 899), Gansu (2.1%, 29/1 377), Chongqing (1.8%, 64/3 523) reported relatively high revision rates. Conclusions: The overall PJI revision rate in 34 hospitals nationwide from 2015 to 2017 is 0.96%. The hip-PJI revision rate is slightly higher than that in the knee-PJI. There are differences in revision rates among hospitals in different regions.

Efficacy and safety of pembrolizumab in metastatic urothelial carcinoma: results from KEYNOTE-045 and KEYNOTE-052 after up to 5 years of follow-up

BACKGROUND

Immune checkpoint inhibitors are a standard therapy in metastatic urothelial carcinoma (UC). Long-term follow-up is necessary to confirm durability of response and identify further safety concerns.

PATIENTS AND METHODS

In KEYNOTE-045, patients with metastatic UC that progressed on platinum-containing chemotherapy were randomly assigned 1:1 to receive pembrolizumab or investigator's choice of paclitaxel, docetaxel, or vinflunine. Primary endpoints were progression-free survival per RECIST version 1.1 by blinded independent central review (BICR) and overall survival. In KEYNOTE-052, cisplatin-ineligible patients with metastatic UC received first-line pembrolizumab. The primary endpoint was objective response rate per RECIST version 1.1 by BICR.

RESULTS

A total of 542 patients (pembrolizumab, n = 270; chemotherapy, n = 272) were randomly assigned in KEYNOTE-045. The median follow-up was 62.9 months (range 58.6-70.9 months; data cut-off 1 October 2020). At 48 months, overall survival rates were 16.7% for pembrolizumab and 10.1% for chemotherapy; progression-free survival rates were 9.5% and 2.7%, respectively. The median duration of response (DOR) was 29.7 months (range 1.6+ to 60.5+ months) for pembrolizumab and 4.4 months (range 1.4+ to 63.1+ months) for chemotherapy; 36-month DOR rates were 44.4% and 28.3%, respectively. A total of 370 patients were enrolled in KEYNOTE-052. The median follow-up was 56.3 months (range 51.2-65.3 months; data cut-off 26 September 2020). The confirmed objective response rate was 28.9% (95% confidence interval 24.3-33.8), and the median DOR was 33.4 months (range 1.4+ to 60.7+ months); the 36-month DOR rate was 44.8%. Most treatment-related adverse events for pembrolizumab in either study were grade 1 or 2 and manageable, which is consistent with prior reports.

CONCLUSION

With ∼5 years of follow-up, pembrolizumab monotherapy continued to demonstrate durable efficacy with no new safety signals in patients with platinum-resistant metastatic UC and as first-line therapy in cisplatin-ineligible patients.

CLINICAL TRIAL REGISTRY AND ID

With ClinicalTrials.gov NCT02256436 (KEYNOTE-045); https://clinicaltrials.gov/ct2/show/NCT02256436 and NCT02335424 (KEYNOTE-052); https://clinicaltrials.gov/ct2/show/NCT02335424.

A phase 1 dose escalation study of the pyruvate kinase activator mitapivat (AG-348) in sickle cell disease

Polymerization of deoxygenated hemoglobin S underlies the pathophysiology of sickle cell disease (SCD). In activating red blood cell pyruvate kinase and glycolysis, mitapivat (AG-348) increases adenosine triphosphate (ATP) levels and decreases the 2,3-diphosphoglycerate (2,3-DPG) concentration, an upstream precursor in glycolysis. Both changes have therapeutic potential for patients with SCD. Here, we evaluated the safety and tolerability of multiple ascending doses of mitapivat in adults with SCD with no recent blood transfusions or changes in hydroxyurea or l-glutamine therapy. Seventeen subjects were enrolled; 1 subject was withdrawn shortly after starting the study. Sixteen subjects completed 3 ascending dose levels of mitapivat (5, 20, and 50 mg, twice daily [BID]) for 2 weeks each; following a protocol amendment, the dose was escalated to 100 mg BID in 9 subjects. Mitapivat was well tolerated at all dose levels, with the most common treatment-emergent adverse events (AEs) being insomnia, headache, and hypertension. Six serious AEs (SAEs) included 4 vaso-occlusive crises (VOCs), non-VOC-related shoulder pain, and a preexisting pulmonary embolism. Two VOCs occurred during drug taper and were possibly drug related; no other SAEs were drug related. Mean hemoglobin increase at the 50 mg BID dose level was 1.2 g/dL, with 9 of 16 (56.3%) patients achieving a hemoglobin response of a ≥1 g/dL increase compared with baseline. Mean reductions in hemolytic markers and dose-dependent decreases in 2,3-DPG and increases in ATP were also observed. This study provides proof of concept that mitapivat has disease-modifying potential in patients with SCD. This trial was registered at www.clinicaltrials.gov as #NCT04000165.

Identification of optimal thalassemia screening strategies for migrant populations in Thailand using a qualitative approach

Background

Thalassemia is a common inherited hemoglobin disorder in Southeast Asia. Severe thalassemia can lead to significant morbidity for patients and economic strain for under-resourced health systems. Thailand’s thalassemia prevention and control program has successfully utilized prenatal screening and diagnosis to reduce the incidence of severe thalassemia in Thai populations, but migrant populations are excluded despite having high thalassemia prevalence. We sought to identify key barriers to and facilitators of thalassemia screening and to develop tailored recommendations for providing migrants with access to thalassemia prevention and control.

Methods

We conducted 28 in-depth interviews and 4 focus group discussions (FGDs) in Chonburi, Thailand with Myanmar and Cambodian migrants, Thai healthcare providers, Thai parents of children affected by thalassemia, and migrant agents.

Results

Participant narratives revealed that migrants’ lack of knowledge about the prevalence, manifestations, severity, and inherited nature of thalassemia led to misconceptions, fear, or indifference toward thalassemia and screening. Negative perceptions of pregnancy termination were based in religious beliefs but compounded by other sociocultural factors, presenting a key obstacle to migrant uptake of prenatal screening. Additionally, structural barriers included legal status, competing work demands, lack of health insurance, and language barriers. Participants recommended delivering public thalassemia education in migrants’ native languages, implementing carrier screening, and offering thalassemia screening in convenient settings.

Conclusions

An effective thalassemia prevention and control program should offer migrants targeted thalassemia education and outreach, universal coverage for thalassemia screening and prenatal care, and options for carrier screening, providing a comprehensive strategy for reducing the incidence of severe thalassemia in Thailand and establishing an inclusive model for regional thalassemia prevention and control.

Feasibility of and barriers to thalassemia screening in migrant populations: a cross-sectional study of Myanmar and Cambodian migrants in Thailand

Background

Thalassemia, an inherited hemoglobin disorder, has become a global public health problem due to population migration. Evidence-based strategies for thalassemia prevention in migrants are lacking. We characterized barriers to thalassemia screening and the burden of thalassemia in migrant workers in Thailand.

Methods

Multilingual demographic and KAP surveys were completed by 197 Thai, 119 Myanmar, and 176 Cambodian adults residing in Thailand. Thalassemia awareness, socio-demographic predictors, and knowledge and attitude scores were compared between migrant and Thai subjects. Comprehensive thalassemia testing was performed for migrants.

Results

Migrants had extremely poor thalassemia awareness (4.1%) compared to Thai subjects (79.6%) and had lower thalassemia knowledge scores but similar attitude scores. Surveys identified differing sociodemographic factors predicting awareness in Thai and migrant subjects, as well as key misconceptions likely to hinder thalassemia screening uptake. Nearly all migrants consented to thalassemia testing. We identified abnormal hemoglobin profiles in 52.7% of migrants and a higher projected rate of severe thalassemia births in migrants.

Conclusions

The high burden of thalassemia and tremendous knowledge gap in migrants needs urgent attention. Thalassemia screening was feasible and acceptable in our migrant population. Sociocultural and structural barriers merit further attention when designing thalassemia screening and prevention policies for migrants in Thailand and globally.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-11059-2.

Whole genome sequence-based haplotypes reveal a single origin of the 1393 bp HBB deletion

BACKGROUND

Mutations of HBB give rise to two prevalent haemoglobin disorders-sickle cell disease (SCD) and β-thalassaemia. While SCD is caused by a single base substitution, nearly 300 mutations that downregulate expression of HBB have been described. The vast majority of β-thalassaemia alleles are point mutations or small insertion/deletions within the HBB gene; deletions causing β-thalassaemia are very rare. We have identified three individuals with haemoglobin Sβ0-thalassaemia in which the β0-thalassaemia mutation is caused by a large deletion.

OBJECTIVE

To use whole genome sequence data to determine whether these deletions arose from a single origin.

METHODS

We used two approaches to confirm unrelatedness: pairwise comparison of SNPs and identity by descent analysis. Eagle, V.2.4, was used to generate phased haplotypes for the 683 individuals. The Neighbor-Net method implemented in SplitsTree V.4.13.1 was used to construct the network of haplotypes.

RESULTS

All three deletions involved 1393 bp, encompassing the β-promoter, exons 1 and 2, and part of intron 2, with identical breakpoints. The cases were confirmed to be unrelated. Haplotypes based on 29 SNPs in the HBB cluster showed that the three individuals harboured different βS haplotypes. In contrast, the haplotype harbouring the 1393 bp deletion was the same in all three individuals.

CONCLUSION

We suggest that all the reported cases of the 1393 bp HBB deletion, including the three cases here, are likely to be of the same ancestral origin.

Paper-based microchip electrophoresis for point-of-care hemoglobin testing

Nearly 7% of the world's population live with a hemoglobin variant. Hemoglobins S, C, and E are the most common and significant hemoglobin variants worldwide. Sickle cell disease, caused by hemoglobin S, is highly prevalent in sub-Saharan Africa and in tribal populations of Central India. Hemoglobin C is common in West Africa, and hemoglobin E is common in Southeast Asia. Screening for significant hemoglobin disorders is not currently feasible in many low-income countries with the high disease burden. Lack of early diagnosis leads to preventable high morbidity and mortality in children born with hemoglobin variants in low-resource settings. Here, we describe HemeChip, the first miniaturized, paper-based, microchip electrophoresis platform for identifying the most common hemoglobin variants easily and affordably at the point-of-care in low-resource settings. HemeChip test works with a drop of blood. HemeChip system guides the user step-by-step through the test procedure with animated on-screen instructions. Hemoglobin identification and quantification is automatically performed, and hemoglobin types and percentages are displayed in an easily understandable, objective way. We show the feasibility and high accuracy of HemeChip via testing 768 subjects by clinical sites in the United States, Central India, sub-Saharan Africa, and Southeast Asia. Validation studies include hemoglobin E testing in Bangkok, Thailand, and hemoglobin S testing in Chhattisgarh, India, and in Kano, Nigeria, where the sickle cell disease burden is the highest in the world. Tests were performed by local users, including healthcare workers and clinical laboratory personnel. Study design, methods, and results are presented according to the Standards for Reporting Diagnostic Accuracy (STARD). HemeChip correctly identified all subjects with hemoglobin S, C, and E variants with 100% sensitivity, and displayed an overall diagnostic accuracy of 98.4% in comparison to reference standard methods. HemeChip is a versatile, mass-producible microchip electrophoresis platform that addresses a major unmet need of decentralized hemoglobin analysis in resource-limited settings.

[Effects of preoperative percutaneous transhepatic biliary drainage on surgical treatment of type Ⅲ and Ⅳ hilar cholangiocarcinoma]

Objective: To investigate the effects of preoperative percutaneous transhepatic biliary drainage on surgical treatment of type Ⅲ and Ⅳ hilar cholangiocarcinoma. Methods: Clinical data of 72 patients with hilar cholangiocarcinoma of the Bismuth-Corlette type Ⅲ and Ⅳ treated at Department of General Surgery,First Affiliated Hospital of Bengbu Medical College from January 2010 to December 2017 were analyzed retrospectively.Patients were divided into two groups based on whether PTBD was performed:a drained group and an undrained group.In the drained group,there were 31 patients,20 males and 11 females,aged (59.9±9.7)years (range: 39-73 years).Among them,14 patients underwent hepatectomy with half or more than half of the liver removed (extended hepatectomy)and 17 patients underwent non-anatomical hepatectomy in the hilar region (limited hepatectomy).In the undrained group,there were 41 patients, 26 males and 15 females, aged (60.8±7.8)years(range: 45-75 years).Among them, 17 patients underwent hepatectomy with half or more than half of the liver removed (extended hepatectomy)and 24 patients underwent non-anatomical hepatectomy in the hilar region (limited hepatectomy).Percutaneous transhepatic biliary drainage(PTBD)was used in the drained group.Under the guidance of ultrasound,one or more hepatobiliary ducts could be sufficiently drained,which had good effect and was not restricted by the obstruction location of hilar cholangiocarcinoma.The analysis of the measurement data was performed using t test,and the analysis of the count data was performed using χ(2) test,and the survival curve was plotted using Kaplan-meier method. Results: In total, 72 jaundiced patients with hilar cholangiocarcinoma underwent surgical treatment: 31 had PTBD prior to operation while 41 did not had PTBD.There were significant differences in ALT((93.2±21.4)U/L vs.(207.4±65.1)U/L),AST((87.6±18.1)U/L vs.(188.9±56.6)U/L)and total bilirubin((68.8±12.6)μmol/L vs.(227.5±87.7)μmol/L)between the patients after treatment and those before treatment(t=10.958, P=0.000; t=10.845, P=0.000; t=10.386, P=0.000).Compared with those in the undrained group, the operation time was shorter, the amount of intraoperative bleeding and the incidence of complications were lower in the drained group(t=-2.840, P=0.006; t=-3.698, P=0.000; χ(2)=4.108, P=0.043).There were no perioperative death cases in drained group and 2 perioperative death cases in undrained group.There was no significant difference in R0 resection rate between the two groups(χ(2)=0.778,P=0.378).The 1-,3-,5-year survival rate of patients in the drained group and the undrained group was 72.7%,34.2%, 13.7% and 72.8%, 31.5%, 11.8%, respectively.The difference was not statistically significant(all P>0.05). Conclusions: The preoperative percutaneous transhepatic biliary drainage in patients with hilar cholangiocarcinoma of Bismuth-Corlette type Ⅲ and Ⅳ could effectively shorten operative time, reduce amount of intraoperative bleeding and incidence of postoperative complications,but have no significant effect on the R0 resection rate and survival rate.

Clinical and metabolomic risk factors associated with rapid renal function decline in sickle cell disease

Sickle cell disease (SCD) nephropathy and lower estimated glomerular filtration rate (eGFR) are risk factors for early mortality. Furthermore, rate of eGFR decline predicts progression to end-stage renal disease in many clinical settings. However, factors predicting renal function decline in SCD are poorly documented. Using clinical, laboratory, genetic, and metabolomic data, we evaluated predictors of renal function decline in a longitudinal cohort of 288 adults (mean age 33.0 years). In 193 subjects with 5-year follow-up data, mean rate of eGFR decline was 2.35 mL/min/1.73 m² /year, nearly twice that of African American adults overall. Hyperfiltration was prevalent at baseline (61.1%), and 36.8% of subjects experienced rapid eGFR decline (≥3 mL/min/1.73 m² /year). Severe Hb genotype; proteinuria; higher platelet and reticulocyte counts, and systolic BP; and lower Hb level and BMI were associated with rapid decline. A risk scoring system was created using these 7 variables and was highly predictive of rapid eGFR decline, with odds of rapid decline increasing 1.635-fold for every point increment (P < 0.0001). Rapid eGFR decline was also associated with higher organ system severity score and peak creatinine. Additionally, two metabolites (asymmetric dimethylarginine and quinolinic acid) were associated with rapid decline. Further investigation into longitudinal SCD nephropathy (SCDN) trajectory, early markers of SCDN, and tools for risk stratification should inform interventional studies targeted to slowing GFR decline and improving SCD outcomes.

[Biomechanical study of different kinds of internal fixation for the typeⅠ Hangman fracture, type Ⅱ odontoid fracture and the C(2/3) disc injury: a finite-element analysis]

Objectives: To analyze the biomechanical stability of four kinds of internal fixation for the type Ⅰ Hangman fracture, type Ⅱ odontoid fracture and the C(2/3) disc injury by finite element (FE) analysis. Methods: Thin-section spiral computed tomography (0.5 mm) was performed on C(1) to C(3) region of cervical vertebra in healthy male volunteers.A three-dimensional hexahedral FE model of upper cervical spine was established by software (Mimics, GEOMAGICS, Pro/E and Ansys). Then the weakening of the strength of grid was performed to simulate the FE model of the type Ⅰ Hangman fracture, type Ⅱ odontoid fracture and the C(2/3) disc injury (FE/Fracture), the four internal fixation models: anterior cervical plate+ odontoid screw+ cage (FE/ACP+ OS+ cage), affixing rods from pedicle screws in C(2) to lateral mass screws in C(3)+ odontoid screw + cage (FE/C(2)PS+ C(3)LMS+ OS+ cage), affixing rods from pedicle screws in C(1) to pedicle screws in C(2) and lateral mass screws in C(3) (FE/C(1)PS+ C(2)PS+ C(3)LMS), anterior odontoid screw plate fixation system (FE/AOSP) were simulated on the FE/Fracture model.Flexion, extension, lateral bending and axial rotation were imposed on the FE/Intact, FE/Fracture and the four fixation models respectively. Results: The intact model of upper cervical spine (C(1)-C(3)) was established successfully, consisting of 259 641 nodes and 403 674 units.There was no significant difference among the FE/ACP+ OS+ cage, the FE/ C(2)PS+ C(3)LMS+ OS+ cage and the FE/AOSP of ROMC(1/2).During flexion, extension, left axial rotation and right axial rotation of ROMC(2)-C(3), the FE/AOSP decreased 70.7%, 74.4%, 38.9%, 41.1% respectively compared with the FE/C(1)PS+ C(2)PS+ C(3)LMS.The ROMC(2)-C(3) during flexion, extension, left lateral bending, right lateral bending, left axial rotation and right axial rotation in the FE/AOSP decreased for 82.2%, 82.8%, 73.2%, 64.8%, 72.2%, 81.5% respectively when compared with those in FE/ACP+ OS+ cage.The ROMC(2)-C(3) during flexion, extension, left lateral bending, right lateral bending, left axial rotation and right axial rotation in the FE/AOSP decreased 88.2%, 81.2%, 47.6%, 41.2%, 38.9%, 39.0% respectively when compared with those in FE/C(2)PS+ C(3)LMS+ OS+ cage.The stress concentrated on the connection between plate and screw in the FE/ACP+ OS+ cage, the FE/C(2)PS+ C(3)LMS+ OS+ cage and the FE/C(1)PS+ C(2)PS+ C(3)LMS, while it distributed evenly in the FE/AOSP. Conclusion: Anterior odontoid screw plate fixation system can be used to treat the type Ⅰ Hangman fracture, type Ⅱ odontoid fracture, and the C(2/3) disc injury and can reserve the function of atlanto-axial joint.

Effect of rosuvastatin on high glucose-induced endoplasmic reticulum stress in human umbilical vein endothelial cells

It is well established that endothelial injury plays an essential role in atherosclerotic plaque formation. Accumulating evidence has shown that high glucose levels may detrimentally affect cultured endothelial cells through endoplasmic reticulum (ER) stress. In this study, we investigated the effect of rosuvastatin on high glucose-induced ER stress in human umbilical vein endothelial cells (HUVECs). HUVECs treated with 30 mM glucose were used to simulate high-glucose conditions, and rosuvastatin concentrations ranging from 0.1 to 10 nM were used. Cell viability was analyzed by thiazolyl blue tetrazolium bromide assay, and apoptosis rate was measured using flow cytometry. Expression of GRP78, IRE1α, XBP1s, and CHOP was quantified using western blot and real-time polymerase chain reaction. Compared to cells treated with high glucose alone, cell viability increased and apoptosis rate decreased significantly in the rosuvastatin + high-glucose groups. Furthermore, GRP78, IRE1α, XBP1s, and CHOP expression was downregulated as a result of rosuvastatin administration. These results suggest that rosuvastatin may protect HUVECs from injury induced by high glucose levels, through alleviation of ER stress.

Variants in mitochondrial tRNA gene may not be associated with thyroid carcinoma

Thyroid cancer is a very common form of endocrine system malignancy. To date, the molecular mechanism underlying thyroid cancer remains poorly understood. Studies of oncocytic tumors have led to a hypothesis which proposes that defects in oxidative phosphorylation (OX- PHOS) may result in a compensatory increase in mitochondrial replication and gene expression. As a result, mitochondrial DNA (mtDNA) mutation analysis has become a useful tool to explore the molecular basis of this disease. Among these mutations, mitochondrial transfer RNAs (mttRNAs) are the hot spots for pathogenic mutations associated with thyroid cancer. However, due to its high mutation rate, the role of mt-tRNA variants in thyroid cancer is still controversial. To address this problem, in this study, we reassessed seven reported mt-tRNA variants: tRNA^Asp G7521A, tRNA^Arg T10411C and T10463C, tRNA^Leu(CUN) A12308G, tRNA^Ile G4292C and C4312T, and tRNA^Ala T5655C, in clinical manifestations of thyroid cancer. We first performed the phylogenetic conservation analysis for these variants; moreover, we used a bioinformatic tool to compare the minimum free energy (G) of mt-tRNA with and without mutations. Most strikingly, none of these variants caused the significant change of the G between the wild-type and the mutant form, suggesting that they may not play an important roles in thyroid cancer. In addition, we screened the frequency of the “pathogenic” A12308G alternation in 300 patients with thyroid cancer and 200 healthy controls. We found that there were five patients and three control subjects carrying this variant. It seemed that the A12308G variant may be a common polymorphism in the human population. Taken together, our study indicated that variants in mt-tRNA genes may not play active roles in patients with thyroid cancer.

Corrigendum Effects of probucol on cultured human umbilical vein endothelial cells injured by hypoxia/reoxygenation - Genet. Mol. Res. 15 (1): gmr.15016752

Published online: March 4, 2016 (DOI: 10.4238/gmr.15016752). Corrected after publication: June 3, 2016 (DOI: 10.4238/gmr.150267521). The information of authors' affiliations is as follows: Y. L. Chai(1,2), J.Z. Xu(1), Y.L. Zhang(1) and G.T. Sheng(2). (1)Department of Cardiovascular Medicine, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning, China. (2)No.1 Department of Cardiovascular Medicine, People's Hospital of Jiangxi Province, Nanchang, Jiangxi, China.

Effects of probucol on cultured human umbilical vein endothelial cells injured by hypoxia/reoxygenation

There is increasing evidence suggesting that endoplasmic reticulum stress (ERS) plays an important role in the initiation and development of atherosclerosis. This study was designed to examine the effect of probucol on cultured human umbilical vein endothelial cells (HUVECs) injured by hypoxia/reoxygenation (H/R) and the potential mechanisms involving ERS. Injured HUVECs induced by Na2S2O4 served as an H/R model in vitro. The concentration of probucol in this study ranged from 3 to 27 μM. Cell viability was analyzed using MTT and a lactate dehydrogenase (LDH) assay. The expression of GRP78, X-box-binding protein (XBP)-1, and CHOP (c/EBP-hemologous protein) were quantified using western blot. Compared to cells with H/R injury alone, the results showed that the cell viability increased significantly with probucol, while the LDH leakage rate was significantly lower as analyzed by the LDH assay. Furthermore, the expression levels of GRP78, XBP-1, and CHOP were significantly downregulated. These results indicated that probucol effectively protected HUVEC from injury induced by H/R and that the mechanism might be related to attenuation of ERS.

Mitochondrial ND3 G10398A mutation: a biomarker for breast cancer

Mitochondrial DNA mutations have been found to play important roles in carcinogenesis. The most common G10398A mutation, a non-conservative amino acid substitution from Thr to Ala, seems to be involved in the tumorigenesis of breast cancer. Results from studies concerning this mutation remain inconclusive. In the current study, we first took clinical and molecular datasets from case-control studies to determine the association between the G10398A mutation and breast cancer. We further used the Phylotree to determine the haplogroups of this mutation. The frequencies of this mutation in 500 unrelated healthy controls were also screened. We found that this mutation is very common in the human population, and may be a polymorph.

Influence of colorectal cancer tumor suppressor gene CHD5 methylation on its clinical and pathological characteristics

Recently, abnormal tumor suppressor gene (TSG) methylation has become a hotspot in the research on colorectal cancer (CRC). This study aimed to explore the influence of CHD5 methylation of CRC TSG on its clinical and pathological characteristics. A total of 40 operation samples as well as corresponding tissue specimens were collected from CRC patients treated in the First Affiliated Hospital of Zhengzhou University from January to December in 2014. CHD5 gene methylation in tissue specimens was detected with methylation specific polymerase chain reaction (MSP); moreover, messenger ribose nucleic acid (mRNA) expression of CHD5 in each tissue was tested using reverse transcription-polymerase chain reaction (RT-PCR), and Western blot was applied to detect the expression of CHD5 protein in those tissues and to analyze the correlation between mRNA and protein of cancer tissue CHD5 as well as the relationship between CHD5 methylation and protein expression. Results revealed that the expression rate of CHD5 methylation in 40 normal mucosal tissues, para-carcinoma tissues, adenoma tissues and CRC tissues was 12.5% (5/40), 22.5% (9/40), 47.5% (19/40) and 72.5% (33/40), respectively. The mRNA expression of CHD5 in the above tissues was 0.225±0.276, 0.169±0.231, 0.147±0.159 and 0.013±0.011 and the protein expression of CHD5 was 0.438±0.205, 0.398±0.180, 0.156±0.1 and 0.024±0.311, respectively. Methylation rate of CHD5 was 87% (20/23) in 23 cases of CHD5 protein loss expression and 52.9% (9/17) in 17 cases of CHD5 protein expression. Results of chi-squared test indicated that there was a significant difference in methylation rate (P less than 0.05), that is, the methylation rate of negatively expressed CHD5 protein was obviously higher than positively expressed protein. Thus, it can be concluded that the CHD5 methylation rate rises gradually in the evolution of CRC, which is related to the occurrence and development of CRC. Furthermore, CHD5 mRNA is positively correlated with protein expression and CHD5 gene methylation is associated with protein loss expression. Therefore, TSG CHD5 methylation of rectal cancer has a great effect in influencing its clinical and pathological features.

G6PD Deficiency in an HIV Clinic Setting in the Dominican Republic

Because human immunodeficiency virus (HIV)-infected patients receive prophylaxis with oxidative drugs, those with glucose-6-phosphate dehydrogenase (G6PD) deficiency may experience hemolysis. However, G6PD deficiency has not been studied in the Dominican Republic, where many individuals have African ancestry. Our objective was to determine the prevalence of G6PD deficiency in Dominican HIV-infected patients and to attempt to develop a cost-effective algorithm for identifying such individuals. To this end, histories, chart reviews, and G6PD testing were performed for 238 consecutive HIV-infected adult clinic patients. The overall prevalence of G6PD deficiency (8.8%) was similar in males (9.3%) and females (8.5%), and higher in Haitians (18%) than Dominicans (6.4%; P = 0.01). By logistic regression, three clinical variables predicted G6PD status: maternal country of birth (P = 0.01) and a history of hemolysis (P = 0.01) or severe anemia (P = 0.03). Using these criteria, an algorithm was developed, in which a patient subset was identified that would benefit most from G6PD screening, yielding a sensitivity of 94.7% and a specificity of 97.2%, increasing the pretest probability (8.8-15.1%), and halving the number of patients needing testing. This algorithm may provide a cost-effective strategy for improving care in resource-limited settings.

CTLA4 enhances the osteogenic differentiation of allogeneic human mesenchymal stem cells in a model of immune activation

Allogeneic mesenchymal stem cells (allo-MSCs) have recently garnered increasing interest for their broad clinical therapy applications. Despite this, many studies have shown that allo-MSCs are associated with a high rate of graft rejection unless immunosuppressive therapy is administered to control allo-immune responses. Cytotoxic T-lymphocyte-associated protein 4 (CTLA4) is a co-inhibitory molecule expressed on T cells that mediates the inhibition of T-cell function. Here, we investigated the osteogenic differentiation potency of allo-MSCs in an activated immune system that mimics the in vivo allo-MSC grafting microenvironment and explored the immunomodulatory role of the helper T cell receptor CTLA4 in this process. We found that MSC osteogenic differentiation was inhibited in the presence of the activated immune response and that overexpression of CTLA4 in allo-MSCs suppressed the immune response and promoted osteogenic differentiation. Our results support the application of CTLA4-overexpressing allo-MSCs in bone tissue engineering.

Some aspects of achieving an ultimate accuracy during insertion device magnetic measurements by a Hall probe

An extensive test of a new Senis 2-axis Hall probe was done at the Advanced Photon Source using the Undulator A device and calibration system. This new probe has clear advantages compared with previously used Bell and Sentron Hall probes: very stable zero offset (less than the noise of 0.026 G) and compensated planar Hall effect. It can be used with proper calibration even for first and second field integral measurements. A comparison with reference measurements by long stretched coil shows that the difference in the first field integral measurement results for a 2.4-m-long Undulator A device is between 17 G cm for the best of four Hall probes used for the test and 51 G cm for the worst of them for all gap ranges from 10.5 mm to 150 mm.

Effect of MWCNTs on Gastric Emptying in Mice

After making model of gastric functional disorder (FD), part of model mice were injected intravenously (i.v.) with oxide multi-walled carbon nanotubes (oMWCNTs) to investigate effect of carbon nanotubes on gastric emptying. The results showed that NO content in stomach, compared with model group, was decreased significantly and close to normal level post-injection with oMWCNTs (500 and 800 μg/mouse). In contrast to FD or normal groups, the content of acetylcholine (Ach) in stomach was increased obviously in injection group with 500 or 800 μg/mouse of oMWCNTs. The kinetic curve of emptying was fitted to calculate gastric motility factor k; the results showed that the k of injection group was much higher than FD and normal. In other words, the gastric motility of FD mice was enhanced via injection with oMWCNTs. In certain dosage, oMWCNTs could improve gastric emptying and motility.

Immunological study of allogeneic mesenchymal stem cells during bone formation

Autologous mesenchymal stem cells (MSCs) are limited in their clinical application because tissue-engineered bone cannot be pre-fabricated. Allogeneic MSCs are readily available but carry the risk of transplant rejection. It is not yet clear whether allogeneic MSCs can induce a rejection response during bone formation. In this study, two strains of genetically unmatched mini-pigs were used as experimental animals to study the immunological changes in MSCs in vitro and in vivo when generating bone. Mini-pig MSCs showed low immunogenicity during osteogenesis both in vitro and in vivo, indicating that allogeneic MSCs had little or no immunogenicity in osteosis. In conclusion, allogeneic MSCs are an important source of seed cells for the tissue engineering of bone. This favours the clinical application of pre-constructed tissue-engineered bone.

Optical rectification in an area with a diameter comparable to or smaller than the center wavelength of terahertz radiation

We report the measurement of optically rectified terahertz (THz) wave power relative to the optical excitation area. Rectified THz wave power reaches its maximum when radius r of the optical excitation area is comparable to the center wavelength of the rectified THz radiation. When r is smaller than the center wavelength of the rectified THz radiation, an r(2) relationship is demonstrated. A model based on optical rectification and Bethe's diffraction theory is used to describe this relationship.

Quantitative analysis of agonist-dependent parathyroid hormone receptor trafficking in whole cells using a functional green fluorescent protein conjugate

Many G-protein coupled receptors (GPCRs) undergo ligand-dependent internalization upon activation. The parathyroid hormone (PTH) receptor undergoes endocytosis following prolonged exposure to ligand although the ultimate fate of the receptor following internalization is largely unknown. To investigate compartmentalization of the PTH receptor, we have established a stable cell line expressing a PTH receptor-green fluorescent protein (PTHR-GFP) conjugate and an algorithm to quantify PTH receptor internalization. HEK 293 cells expressing the PTHR-GFP were compared with cells expressing the wild-type PTH receptor in whole-cell binding and functional assays. 125I-PTH binding studies revealed similar Bmax and kD values in cells expressing either the PTHR-GFP or the wild-type PTH receptor. PTH-induced cAMP accumulation was similar in both cell lines suggesting that addition of the GFP to the cytoplasmic tail of the PTH receptor does not alter the ligand binding or G-protein coupling properties of the receptor. Using confocal fluorescence microscopy, we demonstrated that PTH treatment of cells expressing the PTHR-GFP conjugate produced a time-dependent redistribution of the receptor to the endosomal compartment which was blocked by pretreatment with PTH antagonist peptides. Treatment with hypertonic sucrose prevented PTH-induced receptor internalization, suggesting that the PTH receptor internalizes via a clathrin-dependent mechanism. Moreover, co-localization with internalized transferrin showed that PTHR-GFP trafficking utilized the endocytic recycling compartment. Experiments using cycloheximide to inhibit protein synthesis demonstrated that recycling of the PTHR-GFP back to the plasma membrane was complete within 1-2 h of ligand removal and was partially blocked by pretreatment with cytochalasin D, but not nocodazole. We also demonstrated that the PTH receptor, upon recycling to the plasma membrane, is capable of undergoing a second round of internalization, a finding consistent with a role for receptor recycling in functional resensitization.

A study on pathogenicity of hepatitis G virus

AIM: To study the pathogenicity of hepatitis G virus (HGV) and observe the genesis and pathological process of hepatitis G.

METHODS: HGV-RNA in serum was detected by RT-PCR assay. The immunohistochemical assays of liver tissue were performed with HGV monocoloned antibody (McAb) expressed from the region of HGV NS5 nucleic acid sequence. The clinical and pathological data of 52 patients with hepatitis G were discussed. In animal experiment, the Chinese Rhesus monkeys were infected with the serum of a patient with HGV infection. And the dynamic changes in serology and liver histology of animals were observed.

RESULTS: One hundred and fifty-four patients with HGV-RNA positive were selected from 1552 patients with various kinds of hepatitis. Of 154 patients with HGV infection, 52 were infected with HGV only, which accounted for 33.8% (52/154) and 102 with positive HGV-RNA were super-infected with other hepatitis viruses, which accounted for 66.2% (102/154). The clinical and pathological observation showed that the acute and chronic hepatitis could be induced by HGV. The slight abnormality of transaminases ALT and AST in serum of monkeys lasted nearly 12 months and histological results showed a series of pathological changes.

CONCLUSION: HGV is a hepatotropic virus and has pathogenicty.

Quantification of G-Protein Coupled Receptor Internatilization Using G-Protein Coupled Receptor-Green Fluorescent Protein Conjugates with the ArrayScantrade mark High-Content Screening System

Many G-protein coupled receptors (GPCRs) undergo ligand-dependent homologous desensitization and internalization. Desensitization, defined as a decrease in the responsiveness to ligand, is accompanied by receptor aggregation on the cell surface and internalization via clathrin-coated pits to an intracellular endosomal compartment. In this study, we have taken advantage of the trafficking properties of GPCRs to develop a useful screening method for the identification of receptor mimetics. A series of studies were undertaken to evaluate the expression, functionality, and ligand-dependent trafficking of GPCR-green fluorescent protein (GFP) fusion conjugates stably transfected into HEK 293 cells. These GPCR-GFP expressing cells were then utilized in the validation of the ArrayScantrade mark (Cellomicstrade mark, Pittsburgh, PA), a microtiter plate imaging system that permits cellular and subcellular quantitation of fluorescence in whole cells. These studies demonstrated our ability to measure the internalization of a parathyroid hormone (PTH) receptor-GFP conjugate after ligand treatment by spatially resolving internalized receptors. Internalization was time- and dose-dependent and appeared to be selective for PTH. Similar results were obtained for a beta(2)-adrenergic receptor (beta(2) AR)-GFP conjugate stably expressed in HEK 293 cells. The internalized GFP-labeled receptors were visualized as numerous punctate ³spots² within the cell interior. An algorithm has been developed that identifies and collects information about these spots, allowing quantification of the internalization process. Variables such as the receptor-GFP expression level, plating density, cell number per field, number of fields scanned per well, spot size, and spot intensity were evaluated during the development of this assay. The method represents a valuable tool to screen for receptor mimetics and antagonists of receptor internalization in whole cells rapidly.

Rat homolog of sulfonylurea receptor 2B determines glibenclamide sensitivity of ROMK2 in Xenopus laevis oocyte

Recent studies showed that coexpression of Kir6.1 or Kir6.2 with the sulfonylurea receptor (SUR1, SUR2A, or SUR2B) reconstituted an inwardly rectifying, ATP-sensitive K(+) channel that was inhibited by glibenclamide (2, 15-17). Here we report the isolation of a rat homolog of mouse SUR2B (denoted rSUR2B) from a rat kidney cDNA library. The rSUR2B sequence contains a 4,635-bp open reading frame that encodes a 1,545-amino acid polypeptide, showing 67% shared identity with SUR1 (a pancreatic beta-cell isoform) and 98% with both SUR2A (a brain isoform) and SUR2B (a vascular smooth muscle isoform). Consistent with the predicted structures of other members of the ATP-binding cassette (ABC) superfamily, the sequence of rSUR2B contains 17 putative membrane-spanning segments. Also, predicted Walker A and B consensus binding motifs, present in other ABC members, are conserved in the rSUR2B sequence. RT-PCR revealed that rSUR2B is widely expressed in various rat tissues including brain, colon, heart, kidney, liver, skeletal muscle, and spleen. The intrarenal distribution of the rSUR2B transcript was investigated using RT-PCR and Southern blot of microdissected tubules. The rSUR2B transcript was detected in proximal tubule, cortical thick ascending limb, distal collecting tubule, cortical collecting duct, and outer medullary collecting duct, but not medullary thick ascending limb. This distal distribution overlaps with that of ROMK. Coexpression of rSUR2B with ROMK2 cRNA (in 1:10 ratio) in Xenopus laevis oocytes resulted in whole cell Ba(2+)-sensitive K(+) currents that were inhibited by glibenclamide (50% inhibition with 0.2 mM glibenclamide). In contrast, rSUR2B did not confer significant glibenclamide sensitivity to oocytes coinjected with ROMK1 or ROMK3. The interaction between ROMK2 and rSUR2B was further studied by coimmunoprecipitation of in vitro translated rSUR2B and ROMK2. In agreement with the functional data, the rSUR2B protein was coimmunoprecipitated with ROMK2 in the ROMK2-rSUR2B cotranslated samples. Our data demonstrate that ROMK2, but not ROMK1 and ROMK3, can interact with rSUR2B to confer a sulfonylurea-sensitive K(+) channel, implicating SUR proteins in forming and regulating renal ATP-sensitive K(+) channels. The ROMK isoform specificity of glibenclamide effects suggests that the NH(2) terminus of the ROMK protein mediates rSUR2B-ROMK2 interactions.

[Regulation on growth and accumulation of total alkaloid in Leonurus artemisia (Lour.)S.Y. Hu by various microfertilizers]

OBJECTIVE

To trace the effects of various microfertilizers on the growth and accumulation of total alkaloid in Leonurus artemisia.

METHOD

The total alkaloid was determined by spectrophotometry.

RESULT

Microfertilizers of different concentrations could facilitate the growth of L. artemisia in various degrees and Mn-fertilizer of standard concentration and Cu-fertilizer of excessive concentration could help raise the output of the plant markedly by up to 43.6% and 55.2% respectively. Microfertilizers of different concentrations could improve the content of total alkaloid in L. artemisia: Mn-fertilizer of standard concentration and B-fertilizer of excessive concentration could enhance the contents of total alkaloid up to 2.15% and 2.09% respectively. Mn-fertilizer and Cu-fertilizer of standard concentration have been proved very useful in improving the resistibility and ability of the plant to survive summer safely, and Fe-fertilizer of standard concentration could bring the plant an obvious increase of output after surviving summer.

CONCLUSION

Application of Mn-fertilizer of standard concentration is very important for cultivating L. artemisia of excellent quality and high output.

Partially active channels produced by PKA site mutation of the cloned renal K+ channel, ROMK2 (kir1.2)

The activity of the cloned renal K+ channel (ROMK2) is dependent on a balance between phosphorylation and dephosphorylation. There are only three protein kinase A (PKA) sites on ROMK2, with the phosphorylated residues being serine-25 (S25), serine-200 (S200), and serine-294 (S294) (Z.-C. Xu, Y. Yang, and S. C. Hebert. J. Biol. Chem. 271: 9313-9319, 1996). We previously mutated these sites from serine to alanine to study the contribution of each site to overall channel function. Here we have studied each of these single PKA site mutants using the single-channel configuration of the patch-clamp technique. Both COOH-terminal mutations at sites S200A and S294A showed a decreased open channel probability (Po), whereas the NH2-terminal mutation at site S25A showed no change in Po compared with wild-type ROMK2. The decrease in Po for the S200A and S294A mutants was caused by the additional presence of a long closed state. In contrast, the occurrence of the S25A channel was approximately 66% less, suggesting fewer active channels at the membrane. The S200A and S294A channels had different kinetics compared with wild-type ROMK2 channels, showing an increased occurrence of sublevels. Similar kinetics were observed when wild-type ROMK2 was excised and exposed to dephosphorylating conditions, indicating that these effects are specifically a property of the partially phosphorylated channel and not due to an unrelated effect of the mutation.

The A kinase anchoring protein is required for mediating the effect of protein kinase A on ROMK1 channels

In the present study, we have used the two-electrode voltage-clamp and patch-clamp techniques to study the effects of forskolin and cAMP on the ROMK1 channels, which are believed to be the native K+ secretory channels in the kidney. Addition of 1 microM forskolin or 100 microM 8-bromo-cAMP, within 10 min, has no significant effect on the current of ROMK1 channels expressed in Xenopus oocytes. In contrast, application of 1 microM forskolin, within 3 min, significantly increased whole-cell K+ current by 35%, when ROMK1 channels were coexpressed with the A kinase anchoring protein AKAP79, which was cloned from neuronal tissue. Two lines of evidence indicate that the effect of forskolin is mediated by a cAMP-dependent pathway: (i) Addition of 100 microM 8-bromo-cAMP mimics the effect of forskolin and (ii) the effect of forskolin and cAMP is not additive. That AKAP is required for the effect of cAMP is further supported by experiments in which addition of ATP (100 microM) and cAMP (100 microM) restored the activity of run-down ROMK1 channels in inside-out patches in oocytes that coexpressed ROMK1 and AKAP79 but not in those that expressed ROMK1 alone. Moreover, when we used RII, the regulatory subunit of type II protein kinase A, in an overlay assay, we identified a RII-binding protein in membranes obtained from the kidney cortex but not in membranes from oocytes. This suggests that the insensitivity of ROMK1 channels to forskolin and cAMP is due to the absence of AKAPs. We conclude that AKAP may be a critical component that mediates the effect of protein kinase A on the ROMK channels in the kidney.

Localization of the extracellular Ca2+/polyvalent cation-sensing protein in rat kidney

We previously identified transcripts encoding a G protein-coupled, extracellular calcium/polyvalent cation-sensing receptor, RaKCaR, in rat kidney (D. Riccardi, J. Park, W.-S. Lee, G. Gamba, E. M. Brown, and S. C. Hebert. Proc. Natl. Acad. Sci. USA 92:131-135, 1994), which was proposed to provide the mechanism for modulating a variety of renal functions in response to changes in extracellular Ca2+ (E. M. Brown. In: Handbook of Physiology. Bethesda, MD: Am. Physiol. Soc., 1992, sect. 8, vol. 2, chapt. 39, p. 1841-1916; and S. C. Hebert. Kidney Int. 50: 2129-2139, 1996). Here, we examine the cellular and regional distribution of receptor protein by immunofluorescence microscopy using a polyclonal antibody raised against a 22 amino acid region of the NH2 terminus of the receptor. The most intense fluorescence was seen at the basolateral border of cortical thick ascending limb cells. Basolateral staining for the receptor was also detected in medullary thick ascending limbs, in macula densa cells identified by costaining with antibody to brain nitric oxide synthase, NOS-B1, and in distal convoluted tubule cells distinguished by costaining for the apical thiazide-sensitive Na(+)-Cl- cotransporter. Apical anti-RaKCaR staining was detected at the base of the brush border of proximal tubules with decreasing intensity from S1 to S3 segments. In cortical collecting ducts, anti-RaKCaR staining was detected in some, but not all, type A intercalated cells identified by costaining with anti-H(+)-ATPase and anti-AE1 Cl-/HCO3- exchanger antibodies. The present study demonstrates that RaKCaR protein is expressed in many different nephron segments and that the polarity of receptor expression varies with cell type along the nephron. These results suggest potential roles for the extracellular Ca2+/ polyvalent cation-sensing receptor in responding to both circulating and urinary concentrations of divalent minerals and potentially other polyvalent cations (e.g., aminoglycoside antibiotics) to modulate nephron function.

Localization of the ROMK protein on apical membranes of rat kidney nephron segments

The ATP-sensitive, inwardly rectifying K+ channel, ROMK, has been suggested to be the low-conductance ATP-sensitive K+ channel identified in apical membranes of mammalian renal thick ascending limb (TAL) and cortical collecting duct (CCD). Mutations in the human ROMK gene (KIR 1.2) have been identified in kindreds with neonatal Bartter's syndrome. In the present study, we generated polyclonal antibodies raised against both a COOH-terminal (amino acids 252-391) ROMK-maltose binding protein (MBP) fusion protein and an NH2-terminal (amino acids 34-49) ROMK peptide. Affinity-purified anti-ROMK COOH-terminal antibody detected the 45-kDa ROMK protein in kidney tissues and HEK-293 cells transfected with ROMK1 cDNA. The antibody also recognized 85- to 90-kDa proteins in kidney tissue; these higher molecular weight proteins were abolished by immunoabsorption with ROMK-MBP fusion protein and were also detected on Western blots using anti-ROMK NH2-terminal antibody. Immunofluoresence studies using anti-ROMK COOH-terminal antibody showed intense apical staining along the loop of Henle and distal nephron; staining with preimmune and immunoabsorbed serum was negative. When colocalized with distal nephron markers [the thiazide-sensitive cotransporter (rTSC1), the bumetanide-sensitive cotransporter (rBSC1), the vacuolar type H(+)-ATPase, and neuronal nitric oxide synthase (NOS I)], the ROMK protein was found primarily at the apical border of cells in the TAL, macula densa, distal convoluted tubule, and connecting tubule. Within the CCD, the ROMK protein was expressed in principal cells and was absent from intercalated cells. The tubule localization and polarity of ROMK staining are consistent with the distribution of ROMK mRNA and provide more support for ROMK being the low-conductance K+ secretory channel in the rat distal nephron.

Solitary waves in a single-mode fiber with two-photon absorption and bandwidth-limited optical gain

The exact soliton solutions of the nonlinear Schrödinger equation and the extended nonlinear Schrödinger equation with two-photon absorption and bandwidth-limited optical gain, respectively, are given. The results show that both picosecond and femtosecond soliton pulses can be propagated in a single-mode fiber with twophoton absorption and symmetric optical gain with the proper spectral profile.

A new method, distribution-analyzing latex immunoassay (DALIA), to measure specific immunoglobulin G against mite and wheat allergen in human sera

A distribution-analyzing latex immunoassay (DALIA), based on the agglutination of latex particles coupled with mite or wheat allergen, was developed to determine allergen-specific IgG in human sera. The immune complex between chemically coupled-allergen latex and specific IgG was agglutinated specifically and efficiently by employing an IgM-type monoclonal second antibody with strong amplification activity. The extent of agglutination was evaluated by determining the relative ratio of volumes (RV) of agglutinates to residual nonagglutinating particles with a particle counter. This method exhibited a high sensitivity (detection limit < or = 5 units/ml) in the determination of allergen-specific IgG, and no influence of inhibitory factors such as competitive antibodies (specific-IgA, -IgM) and nonspecific IgG (< or = 320 mg/ml) was observed. The concentrations of specific IgG against mite allergen in the sera of 130 allergy patients with atopic dermatitis and 52 normal subjects were 22.3 +/- 12.3 and 16.5 +/- 4.2 units/ml, respectively, and the concentrations of specific IgG against wheat allergen in the same two groups were 5.4 +/- 4.2 and 2.1 +/- 2.2 units/ml, respectively. The coefficients of variation of intra- and interassay ranged from 3.4% to 11.2% in both cases. The present method is an excellent homogeneous immunoassay which may be used as a routine assay that can measure 50 samples per hour without prior treatment.

Spectrophotometric assay of superoxide dismutase activity based on the activated autoxidation of a tetracyclic catechol

A new spectrophotometric assay of superoxide dismutase (SOD) activity is described. The assay is based on the SOD-mediated increase in the rate of autoxidation of 5,6,6a,11b-tetrahydro-3,9,10-trihydroxybenzo[c]fluorene (BXT-01050) in aqueous alkaline solution. This autoxidation yields a chromophore with a maximal absorbance wavelength of 525 nm. The optimized assay of SOD activity is performed at pH 8.8, 37 degrees C, in 50 mM air-saturated 2-amino-2-methyl-1,3- propanediol buffer containing 3 mM boric acid and 0.1 mM diethylenetriaminepentaacetic acid. The kinetic measurement of 525-nm absorbance is performed for 1 min upon addition of BXT-01050. BXT-01050 is stabilized in stock solution acidified at pH 1.5. The SOD activity is determined from the Vs/Vc ratio of the autoxidation rates measured in the presence (Vs) and in the absence (Vc) of sample. One SOD activity unit (U-525) has been defined as the activity that doubles the autoxidation background (Vs/Vc = 2). The equation that fits the standard curve is the same with all studied SODs. Another reagent, 1,4,6-trimethyl-2-vinylpyridinium trifluoromethanesulfonate, directly eliminates interference due to sample mercaptans such as glutathione by means of a very fast alkylation reaction. A fast and reproducible measurement of SOD activity requires only a single determination per sample. At pH 8.8, an optimal assay sensitivity is achieved without strongly affecting the activity of known SODs such as Cu/Zn-, Mn-, or Fe-SOD.

[A study of cyclic nucleotide acids in the serum in patients with myasthenia gravis]

The levels of cAMP and cGMP in serum of 100 patients with myasthenia gravis have been measured by 125I-RIA. The results showed that cAMP and cGMP were higher in the patients than in the controls significantly (P < 0.001). In 33 cases of these patients after using anticholinesterase drugs and prednisone, the levels of cAMP and cGMP reduced significantly. According to our study, we presumed that there would be cyclic nucleotide acid metabolic disturbances in patients with MG and cAMP might play a regulatory role in morbidity of MG.

[Long-term results of small cell lung cancer treated by surgical resection and multimodality therapy]

241 patients with small cell lung cancer (SCLC) were operated in our hospital from 1957 to 1985. The early postoperative mortality was 1.7%. The 5-yr survival rate was 23.2% (56/241). The 10-yr survival rate was 16.5% (15/91) (only 4 patients died during 5-yr to 10-yr after surgery but none of them died of SCLC). We analysed the 5-yr survival group. The 5-yr survival rate for stage I patients was 52.3% (23/44), stage II 34.1% (14/41), stage III 12.8% (19/149) [IIIa12.3% (17/138),IIIb 18.2% (2/11)]. Stage IV 0 (0/3). The P value: I vs IIIaP < 0.001, II vs IIIaP < 0.01. 125 patients received chemotherapy (CT) and/or radiotherapy (RT) postoperatively (group A) and the other 112 cases received surgical resection only (group B). 4 patients (3 IIIa, 1 IIIb) who died in early postoperative period were not counted. The 5-yr survival rate for group A and B was 40.8% (51/125) and 4.5% (5/112) respectively, P < 0.001; for group A and B stage I was 71.4% (20/28) and 18.8% (3/16), P < 0.01;for group A and B stage II was 54.5% (12/22) and 10.5% (2/19), P < 0.01; for group A and B stage IIIa was 25.4% (17/67) and 0 (0/71), P < 0.001. There were no differences in 5-yr survival rate on types of surgical resection and locations of the disease. The present results revealed that the total 5-yr survival rate for SCLC was 23.2%, among them for resection only was 4.5% and for resection plus multimodality therapy was 40.8%.(ABSTRACT TRUNCATED AT 250 WORDS)