Single-crystal growth, structure and thermal transport properties of the metallic antiferromagnet Zintl-phase β-EuIn2As2

Zintl-phase materials have attracted significant research interest owing to the interplay of magnetism and strong spin-orbit coupling, providing a prominent material platform for axion electrodynamics. Here, we report the single-crystal growth, structure, magnetic and electrical/thermal transport properties of the antiferromagnet layer Zintl-phase compound β-EuIn2As2. Importantly, the new layered structure of β-EuIn2As2, in rhombohedral (R3̄m) symmetry, contains triangular layers of Eu2+ ions. The in-plane resistivity ρ(H, T) measurements reveal metal behavior with an antiferromagnetic (AFM) transition (TN ∼ 23.5 K), which is consistent with the heat capacity Cp(H, T) and magnetic susceptibility χ(H, T) measurements. Negative MR was observed in the temperature range from 2 K to 20 K with a maximum MR ratio of 0.06. Unique 4f7J = S = 7/2 Eu2+ spins were supposed magnetically order along the c-axis. The Seebeck coefficient shows a maximum thermopower |Smax| of about 40 μV K-1. The kink around 23 K in the Seebeck coefficient originates from the effect of the antiferromagnetic phase on the electron band structure, while the pronounced thermal conductivity peak at around 10 K is attributed to the phonon-phonon Umklapp scattering. The results suggest that the Eu2+ spin arrangement plays an important role in the magnetic, electrical, and thermal transport properties in β-EuIn2As2, which might be helpful for future potential technical applications.

[The application of 3D bioprinting in ophthalmology]

On the basis of 3D printing technology, 3D bioprinting has emerged with great development potential and good prospects in the field of medicine and tissue engineering. With this technique, different types of cells and biomaterials can be precisely incorporated into 3D anatomical structures, achieving tissue substitutes with superior structures or functions. In recent years, great progress has been made in the application of 3D bioprinting in ophthalmology. This article reviews not only the differences between 3D printing and 3D bioprinting, but also the development, types, characteristics, application, and prospects of 3D bioprinting in the production of eye tissue engineering materials.

[A preliminary study on the prevention of hemorrhage after laparoscopic pancreaticoduodenectomy by wrapping gastroduodenal artery stump in the left external liver lobe and the left caudate lobe]

Objective: To investigate the safety and efficacy of embedding the stump of gastroduodenal artery between the left lateral lobe of the liver and the left caudate lobe to prevent bleeding after laparoscopic pancreaticoduodenectomy. Methods: The clinical data of 41 patients who underwent laparoscopic pancreaticoduodenectomy at the second Hospital of Hebei Medical University from October 2021 to April 2022 were analyzed retrospectively.There were 27 males and 14 females, aged (63.0±9.2)years (range: 48 to 78 years), and the body mass index was (24.1±3.2)kg/m² (range: 15.4 to 31.6 kg/m²). After routine laparoscopic pancreaticoduodenectomy, the stump of gastroduodenal artery was embedded between the left lateral lobe and the left caudate lobe of the liver, and the hepatic parenchyma of the left lateral lobe and the left caudate lobe were sutured with absorbable sutures.The occurrence and recovery of postoperative complications (pancreatic fistula, biliary fistula, postoperative abdominal bleeding, abdominal infection, liver abscess) were observed. Results: All the operations of 41 patients were completed successfully.The operation time was (277.5±52.0) minutes (range: 192 to 360 minutes). The entrapment time of gastroduodenal artery stump was (3.1±0.6) minutes (range: 2.3 to 4.2 minutes), and the intraoperative blood loss (M(IQR)) was 300 (200) ml (range: 50 to 800 ml).The results of ultrasound examination of hepatic artery on the first day after operation showed that the blood flows of hepatic artery were unobstructed.Postoperative pancreatic fistula occurred in 3 cases, including grade B pancreatic fistula in 2 cases (1 case with abdominal infection) and biochemical leakage in 1 case. Three patients with pancreatic fistula were discharged successfully after continuous abdominal drainage. There was no biliary fistula, abdominal bleeding, abdominal infection, liver abscess or postoperative liver dysfunction. Conclusion: The encasement of the gastroduodenal artery stump by the left outer and left caudate lobes of the liver may be an effective way to prevent bleeding from the rupture of the gastroduodenal artery stump after laparoscopic pancreatoduodenectomy, which is easy and safe to perform.

Stover return and nitrogen application affect soil organic carbon and nitrogen in a double-season maize field

Cultivation techniques have an important influence on grain yield of maize. This experiment investigated the effect of stover return (SR) and different nitrogen (N) application rate on soil organic carbon (SOC) composition, soil nutrient and maize yield. Different nitrogen application rate 100 (N100), 150 (N150), 200 (N200), 250 (N250) or 300 (N300) kg ha^-1 applied to the maize field with stover return and without stover return traditional planting (TP) method. Nitrogen application rate and stover return affected the SOC, labile organic carbon (LOC), microbial biomass (MBC), NO₃ ^- -N, NH₄ ⁺ -N and maize yield. Soil N, soil carbon content and maize yield of SR were all higher than TP. The SOC content of SR and TP were 9.67 and 9.19 g kg^-1 , respectively. Nitrogen application was significantly and positively correlated with soil MBC, LOC, SOC, NO₃ ^- -N, NH₄ ⁺ -N and yield. The maximum values of SOC composition, soil nutrients and maize yield were reached at SR with 250 kg ha^-1 . Stover return with application of N 250 kg ha^-1 significantly increased the growth attribute and maize yield in subtropical region compared with traditional planting.

Thermal Dynamics of Charge Density Wave Pinning in ZrTe_{3}

Impurity pinning has long been discussed to have a profound effect on the dynamics of an incommensurate charge density wave (CDW), which would otherwise slide through the lattice without resistance. Here, we visualize the impurity pinning evolution of the CDW in ZrTe_{3} using the variable temperature scanning tunneling microscopy. At low temperatures, we observe a quasi-1D incommensurate CDW modulation moderately correlated to the impurity positions, indicating a weak impurity pinning. As we raise the sample temperature, the CDW modulation gets progressively weakened and distorted, while the correlation with the impurities becomes stronger. Above the CDW transition temperature, short-range modulations persist with the phase almost all pinned by impurities. The evolution from weak to strong impurity pinning through the CDW transition can be understood as a result of losing phase rigidity.

Urinary microRNAs miR-15b and miR-30a as novel noninvasive biomarkers for gentamicin-induced acute kidney injury

MicroRNAs serve as potential biomarkers in various pathological models, and are stable and detectable in biofluids. We investigated the urinary microRNA expression profile in a gentamicin-induced acute kidney injury canine model using RNA sequencing. A total of 234 differentially expressed microRNAs were screened after 12 consecutive days of gentamicin administration (P < 0.05). Six candidate microRNAs (miR-15b, -15b-3p, -16, -30a, -30a-3p, and -30c-2-3p) were selected according to a set criterion, and validated by real-time quantitative PCR. The diagnostic values of these six candidate microRNAs were better than the traditional serum biomarkers (all P < 0.05). Further, using receiver operating characteristic curve analysis, we found that miR-15b and -15b-3p were superior to urinary kidney injury molecule-1 (both P < 0.05). Moreover, miR-15b and -30a levels in the urine samples significantly correlated with their respective levels in the kidney tissue samples (r=0.512 and 0.505, respectively, both P < 0.05). Our data concluded that miR-15b and -30a may be promising biomarkers for renal toxicity.

[Clinical characteristics of recurrent appendicitis]

Objective: To analyze clinical characteristics of recurrent appendicitis. Methods: A retrospective cohort study was carried out. Clinical data of patients who underwent appendectomy due to acute appendicitis confirmed by pathology in the Affiliated Hospital of Qingdao University from January 2011 to December 2015 were analyzed retrospectively. Exclusion criteria: (1) age of less than 18 years;(2) chronic appendicitis; (3) periappendiceal abscess; (4) appendiceal mucocele or mucinous neoplasms; (5) appendiceal neuroendocrine tumors or cancers; (6) appendicitis during pregnancy; (7) concurrent AIDS, hematological disease, autoimmune disease, inflammatory bowel disease or advanced cancer; (8) other simultaneous surgery. A total of 373 patients were enrolled the study. These patients were divided into the recurrent group (133 cases) and the first episode group (240 cases) according to the previous history of antibiotic therapy for acute appendicitis. The prevalence of recurrent appendicitis was calculated, and the clinical characteristics were analyzed, including gender, age, comorbidities and preoperative CT images. Results: Of 373 patients, 209 were male and 164 were female, with a median age of 42 (18 to 88) years. Median recurrent time of the recurrent group was 4 (1 to 60) months. Compared to the first episode group, the recurrent group had higher proportion of age <50 years [71.4% (95/133) vs. 57.5% (138/240), χ(2)=7.081, P=0.008], higher proportion of concurrent diabetes [13.5% (18/133) vs. 5.4% (13/240), χ(2)=7.399, P=0.007], shorter onset time [(41.7±13.6) hours vs. (59.4±56.2) hours, t=-3.286, P=0.001], lower proportion of abdominal tension and rebound pain [57.9% (77/133) vs. 66.7% (160/240), χ(2)=5.065, P=0.024], lower score of modified Alvarado score [(5.6±1.9) point vs. (6.1±1.9) point, t=-2.417, P=0.016], lower WBC count [(10.5±4.6) ×10(9)/L vs. (11.5±4.5)×10(9)/L, t=-1.190, P=0.047], higher percentage of lymphocyte [(19.4±14.7)% vs. (16.1±13.3)%, t=2.069, P=0.039]. In the recurrent group, ratio of length of removed appendix ≥7 cm was higher as compared with the first episode group [44.4% (59/133) vs. 32.9% (79/240), χ(2)=4.808, P=0.028], while the ratio of complicated appendicitis was significantly lower [8.3% (11/133) vs. 22.9% (55/240), χ(2)=10.823, P=0.001]. CT images were available in 129 patients, intraluminal appendicoliths was found in 19 of 50 patients (38%) in the recurrent group, while in 16 of 79 patients (20.3%) in the first episode group, and there was statistically significant difference between the two groups (χ(2)=4.880, P=0.027). Conclusions: Clinical characteristics of recurrent acute appendicitis include age less than 50 years, concurrent diabetes, short onset time, less abdominal tension or rebound pain, low modified Alvarado score, low WBC count, high percentage of lymphocyte, appendix length longer than 7 cm, non-complicated appendicitis and intraluminal appendicoliths.

[Retrospective investigation of spontaneous bloody tears: a report of 27 cases]

Objective: To summarize clinical experience on the clinical feature, etiology and treatment of patients with spontaneous bloody tears as the initial symptom. Methods: Retrospective series of case studies. The clinical data and follow-up data of 27 cases of bloody tears as the first symptom in Lacrimal Center of Ophthalmology, the Third Medical Center of Chinese PLA General Hospital from June 2015 to December 2018 were reviewed. The clinical feature, specific cause, diagnosis, treatment and prognosis of these cases were evaluated. Results: A total of 27 cases were collected in this study. The patients were 10 males (37.0%) and 17 females (63.0%), including 21 adults (≥ 18 years old, 77.8%) and 6 minors (<18 years old, 22.2%). There were 22 monocular cases (81.5%) and 5 binocular cases (18.5%). Five cases (18.5%) were bleeding from the eye and other parts of the body, and 22 cases (81.5%) were bleeding only from the eye. There were 19 cases (70.4%) with hematic epiphora and secretions from the punctum, 3 cases (11.1%) with blood-stained tears, and 7 cases (25.9%) with blood-like tears. With regard to etiology, 6 cases (22.2%) were combined with systemic lesions, one of which was granulomatosis with polyangiitis and five of which (<18 years old) were idiopathic bloody tears. Twenty-one cases (77.8%) were local lesions, including 18 cases only involving the lacrimal system, 2 cases only involving the ocular surface, and 1 case involving both the lacrimal system and the ocular surface. Among the 21 cases with local lesions, 5 cases were induced by foreign body, 6 cases were induced by simple inflammation, and 10 cases were induced by tumor including 1 case with conjunctival benign tumor and 9 cases with tumor of the lacrimal system (5 with malignant tumor and 4 with benign tumor). Patients with idiopathic bloody tears received psychological and medical treatment, and interictal discharge was lengthened. One case of granulomatosis with polyangiitis was treated by trans-nasal endoscopic dacryocystorhinostomy. With the recurrence of granulomatosis and polyangiitis, bloody tears recurred after surgery. One patient with conjunctival hemangioma was untreated. Lesions in the lacrimal duct system were removed and dacryocystorhinostomy was performed. In this study, 2 patients (1 with small cell neuroendocrine carcinoma and 1 with adenoid cystic adenocarcinoma) died and the other had a good prognosis. Conclusions: Among the cases of bloody tears, adults and local lesions are more common. Most of the lesions are located in the lacrimal system and are tumors. The main treatment is to remove the lesions, and if necessary, to expand the resection and reconstruct the lacrimal duct. Idiopathic bloody tears occur in minors, who are gave psychotherapy and necessary medical treatment. (Chin J Ophthalmol, 2020, 56: 53-58).

Development of IGF signaling antibody arrays for the identification of hepatocellular carcinoma biomarkers

Purpose

Our objective was to develop a system to simultaneously and quantitatively measure the expression levels of the insulin-like growth factor (IGF) family proteins in numerous samples and to apply this approach to profile the IGF family proteins levels in cancer and adjacent tissues from patients with hepatocellular carcinoma (HCC).

Experimental Design

Antibodies against ten IGF family proteins (IGF-1, IGF-1R, IGF-2, IGF-2R, IGFBP-1, IGFBP-2, IGFBP-3, IGFBP-4, IGFBP-6, and Insulin) were immobilized on the surface of a glass slide in an array format to create an IGF signaling antibody array. Tissue lysates prepared from patient's liver cancer tissues and adjacent tissues were then applied to the arrays. The proteins captured by antibodies on the arrays were then incubated with a cocktail of biotinylated detection antibodies and visualized with a fluorescence detection system. By comparison with standard protein amount, the exact protein concentrations in the samples can be determined. The expression levels of the ten IGF family proteins in 25 pairs of HCC and adjacent tissues were quantitatively measured using this novel antibody array technology. The differential expression levels between cancer tissues and adjacent tissues were statistically analyzed.

Results

A novel IGF signaling antibody array was developed which allows the researcher to simultaneously detect ten proteins involved in IGF signal pathway with high sensitivity and specificity. Using this approach, we found that the levels of IGF-2R and IGFBP-2 in HCC tissues were higher than those in adjacent tissues.

Conclusion

Our IGF signaling antibody array which can detect the expression of ten IGF family members with high sensitivity and specificity will undoubtedly prove a powerful tool for drug and biomarker discovery.

Development of IGF-1R signaling antibody arrays for the identification of hepatocellular carcinoma biomarkers (161.9)

A novel IGF-1R signaling antibody array was created through immobilizing the antibodies against ten IGF family proteins (IGF-1, IGF-1R, IGF-2, IGF-2R, IGFBP-1, IGFBP-2, IGFBP-3, IGFBP-4, IGFBP-6, and Insulin) on the surface of glass slide in array format. Tissue lysates prepared from patient’s liver cancer tissues and adjacent tissues were then applied to the arrays. The proteins captured by antibodies on the arrays were then incubated with a cocktail of biotinylated detection antibodies and visualized through fluorescence detection system. By comparison with standard protein amount, the exact protein concentrations in the samples can be determined. Using this novel antibody array technology, the expression levels of the ten IGF family proteins in 25 pairs of hepatocellular carcinoma (HCC) and adjacent tissues were quantitatively measured. The different expressions between cancer tissues and adjacent tissues were then statistically analyzed. Using this approach, we found that the levels of IGF-2R and IGFBP-2 in HCC tissues were higher than those in adjacent tissues.

Role of tissue factor in hepatocellular carcinoma genesis, invasion and metastasis

BACKGROUND

Numerous studies indicate that tissue factor (TF), namely tissue thromboplastin, has a close relationship with malignant tumor genesis and progress. It contributes to blood coagulation as well as the regulation of cellular differentiation, the formation of blood vessels, and also tumor recurrence and metastasis. The present study aimed to detect TF expression in hepatocellular carcinoma (HCC) patients and to elucidate its association with prognosis and clinical features of the disease.

METHODS

The plasma TF levels of 50 HCC patients and 30 controls were assayed by ELISA. The expressions of TF mRNA and protein in HCC tissues, adjacent tissues and normal tissues were detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting. The acquired data were analyzed with related clinic-pathological documents. The patients were followed up for five years, and the relationship between TF and prognosis was analyzed.

RESULTS

The plasma TF levels were significantly increased in HCC compared to the controls (P < 0.05), presenting a close relationship with differentiation level, tumor size and hepatocirrhosis occurrence (P < 0.05). There were remarkably higher values in cases of lymphatic metastasis, extrahepatic metastasis and portal tumor thrombus (PTT) (P < 0.05) compared to non-metastasis or non-tumor thrombus, but no significant difference with different focus number or envelope (P > 0.05). The positive rates and the relative expression of TF mRNA in HCC tissue were 63.0% (17/27) and 0.567 ± 0.268, respectively, significantly higher than that in adjacent tissues or normal tissues (P < 0.05). In the patients with positive results, the relative expression intensity varied significantly with different tumor size and index of local invasion and metastasis (P < 0.05). The positive rates and the relative expression intensities of TF protein in HCC tissue were 74.1% (20/27) and 4.093 ± 1.256, respectively, significantly higher than those in adjacent tissue or normal tissue (P < 0.05). In the patients with positive results, the relative expression intensity showed significant difference in different tumor size, differentiation level, and index of local invasion and metastasis (P < 0.05).

CONCLUSIONS

The TF levels were significantly higher in plasma and tissues of HCC patients, presenting a close relationship with the index of invasion and metastasis. It indicated that TF might be related to differentiation and metastasis of HCC.

[Effect of siRNA silenced human tissue factor gene on hepatocellular carcinoma cell invasion and metastasis]

OBJECTIVE

To study the effect of tissue factor (TF) on human hepatocellular carcinoma cells when their inner TF gene was knocked down by RNA interference.

METHODS

The eukaryotic expression vector bearing siRNA sequence that targeted at TF gene was transfected into human hepatocellular carcinoma cell line HepG2. RT-PCR and Western blot were used to detect the changes of TF gene expression. Transwell invasion assay invitro were used to show the invasive ability of HepG2 cells with transfected pGPU6/GFP/Neo-TFsiRNA.

RESULTS

RT-PCR and Western blot analysis showed that HepG2 cells with pGPU6/GFP/Neo-TFsiRNA transfected decreased the endogenous TF gene expression. Correspondingly the mean invading cells was 14 ± 10 for pGPU6/GFP/Neo-TFsiRNA transfection and 128 ± 18 for the NCsiRNA transfection, respectively by the Transwell invasion test in vitro (P < 0.05). The results indicated that the invasive ability of the HepG2 cells with pGPU6/GFP/Neo-TFsiRNA transfected decreased obviously.

CONCLUSIONS

TF is involved in the progression of hepatocellular carcinoma and inhibiting the expression of TF can decrease the invasion and metastasis ability of tumor cell in vitro.

Platelet-targeted microbubbles inhibit re-occlusion after thrombolysis with transcutaneous ultrasound and microbubbles

Microbubbles (MBs) can augment the acoustic cavitation' (US), thereby facilitating the thrombolysis of external ultrasound. But we observed re-thrombosis after successful thrombolysis by MBs and transcutaneous ultrasound in an endothelium injury model. This study was designed to explore whether platelet-targeted MBs can prevent the reformation of thrombi. Arterial injury was induced in canine femoral arteries with balloon, and the arteries were completely thrombotically occluded. The arteries were treated with intra-arterial MBs or platelet-targeted MBs (TMB) and transcutaneous low frequency ultrasound (LFUS) to achieve complete thrombolysis. The arterial flow was monitored with angiogram for 4h following treatment. Results showed that both MBs and TMBs produced successful dissolution of clots in the presence of ultrasound. The re-occlusion began to occur 1h after thrombolysis in MB/LFUS treatment, and 7 of 8 arteries were re-occluded within 3h. Most of the arteries (7 of 8) in the TMB/LFUS group remained patent for 4h following treatment. The flow tended to decrease after thrombolysis in MB/LFUS treatment. These results indicated that platelet-targeted microbubbles were beneficial in preventing re-thrombosis in vivo and microbubbles served as good carrier of thrombolytic and anticoagulation drugs.

Water and phosphorus content affect PAH dissipation in spiked soil planted with mycorrhizal alfalfa and tall fescue

Polycyclic aromatic hydrocarbon (PAH) dissipation efficiency can be increased in the plant rhizosphere, but may be affected by various environmental factors. We investigated the effects of the watering regime and phosphorus concentration on PAH dissipation in the rhizosphere of mycorrhizal plants in a pot experiment. Two plant species, alfalfa (Medicago sativa) and tall fescue (Festuca arundinacea), were co-cultured and inoculated with an arbuscular mycorrhizal (AM) fungus (Glomus intraradices) in PAH (phenanthrene (PHE)=500 mg kg(-1), pyrene (PYR)=500 mg kg(-1), dibenzo(a,h)anthracene (DBA)=65 mg kg(-1)) spiked agricultural soil for 6 weeks. Treatments with different phosphorus concentrations and watering regimes were compared. The PHE dissipation reached 90% in all treatments and was not affected by the treatments. The major finding was the significant positive impact of mycorrhizal plants on the dissipation of high molecular weight PAH (DBA) in high-water low-phosphorus treatment. Such an effect was not observed in high-water high-phosphorus and low-water low-phosphorus treatments, where AM colonization was very low. A positive linear relationship was detected between PYR dissipation and the percentage of Gram-positive PAH-ring hydroxylating dioxygenase genes in high-water high-phosphorus treatments, but not in the other two treatments with lower phosphorus concentrations and water contents. Such results indicated that the phosphorus and water regime were important parameters for the dissipation of HMW-PAH.

Influence of guanidine on proteinase K resistance in vitro and infectivity of scrapie prion protein PrP(Sc)

As the scrapie prion protein PrP(Sc) is rich in beta-sheets it aggregates into prion rods, which show infectivity and proteinase K (PK) resistance. Consequently, dissociation of prion rods and breakdown of beta-sheets in PrP(Sc) by denaturation results in loss of both infectivity and PK-sensitivity. In this study, the effects of guanidine (Gdn), which solubilizes and denatures proteins by breaking down their higher structure, on the solubility, the PK-resistance in vitro and the infectivity of PrP(Sc) of scrapie strain 263K was examined. The infectivity was assayed by intracerebral inoculation into hamsters. Brain tissues of scrapie-infected hamsters were used for preparation of homogenates and crude extracts of PrP(Sc). A treatment of PrP(Sc) with Gdn enhanced its PK-sensitivity in a dose-dependent manner. The PK-resistance in vitro of PrP(Sc) denatured with lower concentrations of Gdn (<2.5 mol/l) could partially resume by renaturation. Gdn markedly reduced or, at higher concentrations, even destroyed the infectivity of PrP(Sc). On the other hand, the infectivity of PrP(Sc) inactivated by denaturation could be partially restored by renaturation. These results confirmed our assumption that all the alternations in the PK-resistance and the infectivity of PrP(Sc) caused by Gdn resulted from changes in its higher structure. However, it should be emphasized that a complete loss of PK-resistance of PrP(Sc) may not necessarily mean its full non-infectivity.

Applied anatomy of the V-shaped fibular osteomyocutaneous flap in reconstruction of the hindfoot

To establish the applied anatomy of the V-shaped fibular osteomyocutaneous flap pedicled on the peroneal vessels, cadaver dissections were made in 60 lower limbs and 40 calcanei were examined to sum up the features of calcaneal biomechanics on the stability of the foot and the blood supply of the fibular osteomyocutaneous flap. There were four anastomoses and large communicating branches between the lower segment of the peroneal artery and the anterior and posterior tibial arteries. The flap was well supplied by a retrograde circulation through these anastomoses. A suitable length of pedicle was 20 cm. In the sagittal section of the calcaneus passing through the center of the articular surface for the cuboid bone, the arrangement of the trabeculae formed a triangular zone. The V-shaped flap corresponds nicely with the calculated lines of stress evoked by the weight of the body. The procedure may provide a new method for hindfoot reconstruction. This flap meets the criteria outlined for composite tissue reconstruction of defects of the extremities and biomechanics of the hindfoot, especially for calcaneal and cuboid defects.

A molecular switch for specific stimulation of the BKCa channel by cGMP and cAMP kinase

The cGMP and the cAMP pathways control smooth muscle tone by regulation of BK(Ca) (BK) channel activity. BK channels show considerable diversity and plasticity in their regulation by cyclic nucleotide-dependent protein kinases. The underlying molecular mechanisms are unclear but may involve expression of splice variants of the BK channel alpha subunit. Three isoforms, BK(A), BK(B), and BK(C), which were cloned from tracheal smooth muscle, differed only in their C terminus. When expressed in HEK293 cells, cGMP kinase (cGK) but not cAMP kinase (cAK) stimulated the activity of BK(A) and BK(B) by shifting the voltage dependence of the channel to more negative potentials. In contrast, BK(C) was exclusively stimulated by cAK. BK(C) lacks a C-terminal tandem phosphorylation motif for protein kinase C (PKC) with Ser(1151) and Ser(1154). Mutation of this motif in BK(A) switched channel regulation from cGK to cAK. Furthermore, inhibition of PKC in excised patches from cells expressing BK(A) abolished the stimulatory effect of cGK but allowed channel stimulation by cAK. cAK and cGK phosphorylated the channel at different sites. Thus, phosphorylation/dephosphorylation by PKC determines whether the BK channel is stimulated by cGK or cAK. The molecular mechanisms may be relevant for smooth muscle relaxation by cAMP and cGMP.

Effects of doxorubicinol on excitation--contraction coupling in guinea pig ventricular myocytes

The cardiotoxicity of the anticancer drug doxorubicin may be related to its main metabolite doxorubicinol. In this study, the acute effects of doxorubicinol on excitation-contraction coupling in isolated guinea pig ventricular myocytes were investigated and compared with doxorubicin using the whole-cell patch-clamp-, fura-2 fluorescence- and cell-edge tracking techniques. Both drugs were applied intracellularly by diffusion from the patch electrode for 15--20 min. Doxorubicin (100 microM) prolonged the action potential duration (APD) by 31% and enhanced cell shortening by 26%. Contrary to doxorubicin, doxorubicinol (10 microM) shortened APD by 25% and decreased cell shortening by 31%. APD shortening by doxorubicinol was due to an increase of the delayed rectifier K(+) current. Neither the inward rectifier K(+) current nor the L-type Ca(2+) current was influenced by doxorubicinol. The decline in cell shortening induced by doxorubicinol was not exclusively due to APD shortening because doxorubicinol reduced the peak Ca(2+) transient by 23% in cells clamped with an action potential of constant duration. Despite opposite effects on APD and contractility, both doxorubicin and doxorubicinol produced a considerable delay in the activation and inactivation of contraction and Ca(2+) transient, compatible with an impaired function of the sarcoplasmic reticulum. It is suggested that doxorubicinol-induced APD shortening may amplify the detrimental effects of both doxorubicin and doxorubicinol on sarcoplasmic reticulum Ca(2+) load and hence on contractile function. The accumulation of doxorubicinol in the cardiac myocytes may play an important role in the time-dependent development of doxorubicin-induced ventricular dysfunction.

BK(Ca) channel activation by membrane-associated cGMP kinase may contribute to uterine quiescence in pregnancy

We investigated the influence of pregnancy on large-conductance calcium-activated potassium channel (BK(Ca)) activity (NP(o)) and on channel expression in membranes of isolated human myometrial smooth muscle cells. NP(o) in inside-out patches was higher in pregnant myometria (PM) compared with nonpregnant myometria (NPM), and the half-maximal activation potential was shifted by 39 mV to more negative potentials. This effect was not due to an enhanced BK(Ca) channel expression. In the presence of cAMP kinase (PKA) or cGMP kinase (PKG), NP(o) increased in patches from PM but decreased in those from NPM. Western blot analysis and use of a specific PKG inhibitor (1 microM KT-5823) verified the existence of a partially active membrane-associated PKG. Inhibition of PKA by 100 nM PKI, the inhibitory peptide of PKA, had no effect on NP(o). 8-p-Chlorophenylthio-cGMP (8-pCPT-cGMP) hyperpolarized cells from PM. This effect was abolished by iberiotoxin, a specific blocker of BK(Ca) channels. It is concluded that an endogenous, membrane-bound PKG in myometrial cells specifically enhances BK(Ca) channel activity during pregnancy and thus may contribute to uterine quiescence during pregnancy.

[Effect of heparinoid derived from porcine duodenum on the proliferation of cultured smooth muscle cells]

AIM

To study the antiproliferative effect of haparinoid derived from porcine duodenum (heparinoid) on cultured vascular smooth muscle cells.

METHODS

Cultured bovine aortic smooth muscle cells (BASMCs) of 5-10 passages were seeded into 24 and 72-well cluster culture plates and were synchronized by 48 h serum deprivation. Then, the cells were re-stimulated by serum repletion with or without heparinoid. The antiproliferative effect of heparinoid was evaluated by crystal violet staining and MTT assay 72 h after serum repletion. To study the drug action on cytomorphological changes, three kinds of cells [quiescent cells, cells treated with 10% fetal calf serum (FCS) with or without heparinoid] were observed by transmission electron microscopy. After synchronized and re-stimulated as above, BASMCs were treated with heparinoid 0.8 mg.mL-1 at selected points during serum repletion. The cells were harvested at specified times after serum repletion, then cellular DNA contents (to estimate the proportions of cells in different phases of the cell cycle) and the contents of alpha-actin, c-myc and c-fos proteins were measured by flow cytometry.

RESULTS

Heparinoid was shown to inhibit the proliferation of BASMCs induced by 10% FCS. The inhibitory effect was weakened when heparinoid was added 2 h after serum repletion, and there was no antiproliferative effect when heparinoid was added 12 h after serum repletion. Electron micrographs showed that cells treated with 10% FCS and heparinoid expressed a contractile phenotype, while cells treated with 10% FCS only expressed a synthetic phenotype. Flow cytometry study showed remarkable increase of alpha-actin, and decrease of c-myc and c-fos proteins in the cells treated with heparinoid.

CONCLUSION

Heparinoid was found to inhibit the proliferation of BASMCs. The antiproliferative effect occurred at the early phase of the cell cycle. It might be due to the drug's influence on cell phenotype modulation and the down regulation of c-myc and c-fos proto-oncogenes expression.

Polarity exchange at the interface of regulators of G protein signaling with G protein alpha-subunits

RGS proteins are GTPase-activating proteins (GAPs) for G protein alpha-subunits. This GAP activity is mediated by the interaction of conserved residues on regulator of G protein signaling (RGS) proteins and Galpha-subunits. We mutated the important contact sites Glu-89, Asn-90, and Asn-130 in RGS16 to lysine, aspartate, and alanine, respectively. The interaction of RGS16 and its mutants with Galpha(t) and Galpha(i1) was studied. The GAP activities of RGS16N90D and RGS16N130A were strongly attenuated. RGS16E89K increased GTP hydrolysis of Galpha(i1) by a similar extent, but with an about 100-fold reduced affinity compared with non-mutated RGS16. As Glu-89 in RGS16 is interacting with Lys-210 in Galpha(i1), this lysine was changed to glutamate for compensation. Galpha(i1)K210E was insensitive to RGS16 but interacted with RGS16E89K. In rat uterine smooth muscle cells, wild type RGS16 abolished G(i)-mediated alpha(2)-adrenoreceptor signaling, whereas RGS16E89K was without effect. Both Galpha(i1) and Galpha(i1)K210E mimicked the effect of alpha(2)-adrenoreceptor stimulation. Galpha(i1)K210E was sensitive to RGS16E89K and 10-fold more potent than Galpha(i1). Analogous mutants of Galpha(q) (Galpha(q)K215E) and RGS4 (RGS4E87K) were created and studied in COS-7 cells. The activity of wild type Galpha(q) was counteracted by wild type RGS4 but not by RGS4E87K. The activity of Galpha(q)K215E was inhibited by RGS4E87K, whereas non-mutated RGS4 was ineffective. We conclude that mutation of a conserved lysine residue to glutamate in Galpha(i) and Galpha(q) family members renders these proteins insensitive to wild type RGS proteins. Nevertheless, they are sensitive to glutamate to lysine mutants of RGS proteins. Such mutant pairs will be helpful tools in analyzing Galpha-RGS specificities in living cells.

Effects of mitoxantrone on excitation-contraction coupling in guinea pig ventricular myocytes

The mechanisms of the inotropic effect of mitoxantrone (MTO), a synthetic dihydroxyanthracenedione derivative with antineoplastic activity, was investigated in guinea pig ventricular myocytes using whole-cell patch-clamp methods combined with fura-2 fluorescence and cell-edge tracking techniques. In right ventricular papillary muscles, 30 microM MTO increased isometric force of contraction as well as action potential duration (APD) in a time-dependent manner. The force of contraction was increased approximately 3-fold within 4 h. This positive inotropic effect was accompanied by a prolongation of time to peak force and relaxation time. In current-clamped single myocytes treated with 30 microM MTO for 30 min, an increase of cell shortening by 77% and a prolongation of APD by 19% was observed. Peak amplitude of the intracellular Ca(2+) transients was also increased by 10%. The contribution of APD prolongation to the enhancement of cell shortening induced by MTO was assessed by clamping control myocytes with action potentials of various duration. Prolongation of APD(90) (ADP measured at 90% of repolarization) by 24% led to an increase of cell shortening by 13%. When the cells were clamped by an action potential with constant APD, MTO still caused an increase of cell shortening by 59% within 30 min. No increase of the peak intracellular Ca(2+) transients, however, was observed under this condition. We conclude that both the APD prolongation and a direct interaction with the contractile proteins contributed to the positive inotropic effect of MTO.

Pregnancy switches adrenergic signal transduction in rat and human uterine myocytes as probed by BKCa channel activity

1. We used large conductance Ca2+-activated K+ (BKCa) channel activity as a probe to characterize the inhibitory/stimulatory G protein (Gi/Gs) signalling pathways in intact cells from pregnant (PM) and non-pregnant (NPM) myometrium. 2. Isoprenaline (10 microM) enhanced the outward current (Iout) in PM cells and inhibited Iout in NPM cells. Additional application of the alpha2-adrenoceptor (alpha2-AR) agonist clonidine (10 microM) further enhanced the isoprenaline-modulated Iout in PM cells but partially antagonized Iout in NPM cells. Clonidine alone did not affect Iout. The specific cAMP kinase (PKA) inhibitor H-89 (1 microM) abolished the effects of isoprenaline and clonidine. The specific BKCa channel blocker iberiotoxin (0.1 microM) inhibited Iout by approximately 80 %; the residual current was insensitive to isoprenaline. 3. Inhibition of Gi activity by either pertussis toxin or the GTPase activating protein RGS16 abolished inhibitory as well as stimulatory effects of clonidine on Iout. 4. Transducin-alpha, a scavenger of Gi betagamma dimers, converted the stimulatory action of clonidine on Iout into an inhibitory effect. Free transducin-betagamma enhanced both the stimulatory and the inhibitory effects of isoprenaline on Iout. 5. The results demonstrate that BKCa channel activity is a sensitive probe to follow adenylyl cyclase-cAMP-PKA signalling in myometrial smooth muscle cells. Both Gialpha-mediated inhibition and Gibetagamma-mediated stimulation can occur in the same cell, irrespective of pregnancy. It is speculated that the coupling between alpha2-AR and Gi proteins is more efficient during pregnancy and that Gibetagamma at high levels simply override the inhibitory action of Gi alpha.

[Relation between myocardial cAMP and renin-angiotensin system activation after acute pressure overload]

In order to investigate the relationship between cAMP and myocardial renin-angiotensin system activation after acute pressure overload, an animal model of acute pressure overload was established by constriction of abdominal aorta. It was found that angiotensin converting enzyme (ACE) mRNA and protein expression were increased markedly, ACE activity and angiotensin II content were also elevated significantly in rat heart 1 h after acute pressure overload, and the increases were kept at high level. Meanwhile the myocardial cAMP concentration was increased significantly at 0.5 h, reached the peak at day 5, and returned to normal at day 30 after operation. Then cardiomyocytes were cultured to observe whether ACE gene expression can be induced by cAMP. The results showed that elevation of cAMP content in cultured cardiomyocytes stimulated by isoproterenol (ISO, 0.01 micromol/L) increased ACE mRNA and protein expression, and also increased ACE activity and Ang II content in cultural medium. These results suggest that cAMP plays a role in the mechanism of activation of myocardial renin-angiotensin system induced by pressure overload.

User acceptability of a female condom (Reality) in Shanghai

Thirty married couples evaluated the Reality female condom on questionnaires about its acceptability for 300 acts of coitus (10 per couple). An analysis of the summary questionnaires showed: 90% of couples considered the female condom an acceptable method and 87% felt it was a good contraceptive device; the majority of couples (87%) found it easy to use; and 80% of females and 73% of males reported that, in comparison with the male condom, the effect on sexual pleasure was either improved or no different. A little more than half of the couples (55%) preferred it to male condoms. To look at the learning curve effect, an additional analysis was completed by pooling the first 5 applications of each user and comparing the results with the pooled results of the second 5 uses. All the findings suggest that a certain proportion of couples of childbearing age will choose the Reality female condom for contraception if it enters into the Chinese market. As a new contraceptive barrier device, the female condom may require a certain amount of education and awareness before it will be fully recognized as an important option to help prevent pregnancy as well as sexually transmitted infections.

Regulation of stably expressed and native BK channels from human myometrium by cGMP- and cAMP-dependent protein kinase

The cloned BK channel alpha subunit from human myometrium was stably expressed in Chinese hamster ovary cells, either alone (CHOalpha cells) or in combination with the auxiliary beta subunit (CHOalpha+beta cells). We studied basic channel properties and the effects of cGMP- and cAMP-dependent protein kinases on the BK channel activity. Coexpression of alpha and beta subunits enhanced the Ca2+ and voltage sensitivity of the BK channel, and decreased the inhibitory potency of iberiotoxin. Blocking and stimulating effects on BK channel activity by charybdotoxin and nitric oxide, respectively, were independent of the beta subunit. The cGMP kinase Ialpha and cAMP kinase failed to affect BK channel activity in CHOalpha and CHOalpha+beta cells at different [Ca2+]i and voltages. In contrast, BK channels in freshly isolated myometrial cells from postmenopausal women responded to cAMP kinase and cGMP kinase with a fourfold and twofold decrease in their open probability (NPo), respectively. These effects could be reversed by alkaline phosphatase and remained unaffected by the phosphatase inhibitor okadaic acid (100 nM). In 28% of myometrial cells, however, cAMP and cGMP kinases increased NPo 2-fold and 3.5-fold, respectively. This stimulation was enhanced rather than reversed by alkaline phosphatase and was abolished by 100 nM okadaic acid. The results suggest that in stably transfected CHO cells the expressed BK channel is not regulated by cAMP kinase and cGMP kinase. However, in native myometrial cells stimulatory and inhibitory regulation of BK channels by cAMP kinase and cGMP kinase was observed, suggesting that channel regulation by the protein kinases requires factors that are not provided by CHO cells. Alternatively, failure of regulation may have been due to the primary structure of the myometrial BK channel protein used in this study.

Inhibitory effects of berberine on ATP-sensitive K+ channels in cardiac myocytes

The effects of berberine on cardiac action potentials were measured in isolated guinea-pig papillary muscles exposed to hypoxia and cromakalim using the standard microelectrode technique. In addition, the patch clamp technique was used to determine the effects of berberine on cromakalim-induced outward currents in isolated ventricular myocytes and on ATP-sensitive K+ (KATP) channels in inside-out membrane patches. Berberine, at 3 microM significantly inhibited, while at 100 microM completely blocked the shortening of action potential duration and effective refractory period induced by hypoxia or cromakalim (100 microM). Under the whole-cell voltage clamp conditions, berberine (3-100 microM) attenuated or even abolished the cromakalim-elicited outward K+ currents. Berberine (3-100 microM) inhibited KATP channel activity in a concentration-dependent fashion in inside-out membrane patches exposed to 0.1 mM ATP. This inhibition appeared to be mainly due to a decrease in the open channel probability without affecting unitary conductance or the time constants for open and closed channel times. Glibenclamide (10 microM) partially blocked the hypoxia-evoked but fully reversed the cromakalim-evoked abbreviation of action potential duration and effective refractory period. Both the whole-cell outward K+ currents induced by cromakalim and the opening of single KATP channels induced by the low intracellular ATP concentration were also completely abolished by 10 microM glibenclamide. We conclude that berberine is a blocker of the cardiac KATP channel. The reported beneficial effect of berberine on ischemia-induced arrhythmias is likely attributed to its inhibition of KATP channel activation and subsequent shortening of action potential duration and effective refractory period during ischemia.

Protein phosphatase 2A is essential for the activation of Ca2+-activated K+ currents by cGMP-dependent protein kinase in tracheal smooth muscle and Chinese hamster ovary cells

The regulation of Ca2+-activated K+ channels (KCa channels) by cGMP-dependent protein kinase (cGMP kinase) and its molecular mechanism were investigated in Chinese hamster ovary (CHO) and tracheal smooth muscle cells. In CHO wild-type cells (CHO-WT cells) and in CHO cells stably transfected with cGMP kinase Ialpha (CHO-cGK cells), KCa channels with intermediate conductance (approximately 50 picosiemens) were identified. Due to the basal activity of cGMP kinase, Ca2+-activated K+ currents had a higher sensitivity toward the cytosolic Ca2+ concentration in CHO-cGK cells than in CHO-WT cells. Dialysis of the active fragment of cGMP kinase (300 n) into CHO-WT cells or of cGMP into CHO-cGK cells increased the Ca2+-activated K+ current, while the catalytic subunit of cAMP-dependent protein kinase (cAMP kinase) was without effect. In cell-attached patches obtained from freshly isolated bovine tracheal smooth muscle cells, the open state probability (NPo) of maxi-KCa channels (conductance of approximately 260 picosiemens) was enhanced by 300 microM 8-(4-chlorophenylthio)-cGMP, a specific and potent activator of cGMP kinase. In contrast, 1 microM isoprenaline, 20 microM forskolin, and 3 mM 8-bromo-cAMP failed to enhance KCa channel activity. In excised inside-out patches, only the active fragment of cGMP kinase (but not that of cAMP kinase) increased NPo when applied to the cytosolic side of the patch. The enhancement of NPo by cGMP kinase was inhibited in CHO cells as well as in tracheal smooth muscle cells by the cGMP kinase inhibitor KT 5823 (1 microM) and the protein phosphatase (PP) inhibitors microcystin (5 microM) and okadaic acid (10 nM). The catalytic subunit of PP2A (but not that of PP1) mimicked the effect of cGMP kinase on NPo in excised inside-out patches. The results show that cGMP kinase regulates two different KCa channels in two unrelated cell types by the same indirect mechanism, which requires the activity of PP2A. The regulation of the KCa channel is specific for cGMP kinase and is not mimicked by cAMP kinase.

[Effect of Japanese Ganoderma Lucidum on production of interleukin-2 from murine splenocytes]

The purpose of this study was to determine the effect of Ganoderma lucidum (GL) planted in Japan on the production of Interleukin-2 (IL-2) from murine splenocytes. It was observed that hydrocortisone (HC) 0.025-1 microgram /ml could significantly antagonize the inhibitory activity of HC and CSA to increase the production of IL-2 in vitro, P < 0.01. When the splenocytes pretreated with GL alone or in combination with HC, it was shown that pretreatment alone had no significant effect on IL-2 production, but preincubating splenocytes with HC and GL resulted in a significant increase of IL-2 production when compared with that of HC group, P < 0.01. In vivo, GL 300 mg/kg could increase the production of IL-2 when oral taken GL alone or in combination of HC.

[A comparative study on cholagogic effect of Artemisia]

The result suggests that the cholagogic effect of A. anethoides, A. haichowenesis and A. capillaris are not different significantly (P > 0.05), but the duration of action caused by anethoides and haichowenesis is longer than that caused capillaris. The cholagogic effect of A. capillaris collected in seedling, flower budding (beginning of autumn) and preflower periods were also investigated separately, and the preflower collection was found more cholagogic.

[Experimental study of the effect on the liver of cortisol after diverting the adrenal venous circulation into the portal circulation]

In order to evaluate the operation of the adrenal autotransplantation into omentum with arterio-venous anastomosis, the right adrenal of fifteen dogs was preliminarily removed and then the left adrenal vein was diverted into the portal circulation by micro surgical technique. Before and after the diversion, the serum cortisol taken from portal vein, hepatic vein, inferior vena cava and peripheral vein was analysed by radioimmunoassay. The dog's adrenal cortex, pituitary were removed for light and electron-microscopic examination. The experimental results demonstrate that the cortisol inactivation effect of the liver was not statistically different before and after the procedure (P greater than 0.05). Thus, we believe that the omentum which has obvious absorbability and revascularity is a reasonable site for adrenal transplantation. And we also found the adrenal cortex left appear slight hypotrophy and pituitary hypertrophy after the diversion. The cause however, requires further research.