[Updates of colonoscopy surveillance guidelines after screening and polypectomy, and related research progress]

With the widespread application of colorectal cancer screening, the surveillance and management of the increasing number of screened population has become a pivotal aspect in preventing and controlling colorectal cancer. In recent years, researches have been conducted on the risk of colorectal cancer incidence and mortality in the population after screening. At the same time, various organizations in Europe and the United States have continuously updated colonoscopy surveillance after screening and polypectomy based on the latest research evidence. In this review, we summarized the current progress of studies on colorectal cancer risk in post-screening colorectal cancer populations and the key points of relevant guideline updates, in order to provide a reference for conducting relevant studies and formulating surveillance guidelines or consensus in China.

Design, synthesis and evaluation of 2-pyrimidinylindole derivatives as anti-obesity agents by regulating lipid metabolism

Obesity, a global pandemic posing a growing threat to human health, necessitates the development of effective and safe anti-obesity agents. Our previous studies highlighted the lipid-lowering effects of indolylquinazoline Bouchardatine and its derivatives. In this study, we employed scaffold hopping and simplification strategies to design and synthesize two new series derivatives by modifying the D ring. Extensive discussions have been conducted regarding the structure-activity relationship between lipid-lowering activity and the new compounds. These discussions have resulted in the discovery of 2-pyrimidinylindole derivatives as a promising scaffold for anti-obesity treatment. The new 2-pyrimidinylindole derivatives exhibited comparable lipid-lowering activity to the previously reported indolylquinazoline derivatives, including SYSU-3d and R17, with reduced toxicity. The most potent compound, 5a, demonstrated a larger therapeutic index, improved aqueous solubility and oral bioavailability compared to the previous lead compounds. In vivo evaluation indicated that 5a effectively reduced lipid accumulation in adipose tissue, improved glucose tolerance, and mitigated insulin resistance and liver function damage caused by a high-fat and high-cholesterol diet. Mechanism studies indicated that 5a may regulate lipid metabolism through the modulation of the PPARγ signaling pathway. Overall, our study has identified a highly active compound 5a, and provided the basis for further development of 2-pyrimidinylindole as a promising scaffold for obesity treatment.

Design and Synthesis of Bouchardatine Derivatives as a Novel AMP-Activated Protein Kinase Activator for the Treatment of Colorectal Cancer

Metabolic reprogramming is a crucial hallmark of tumorigenesis. Modulating the reprogrammed energy metabolism is an attractive anticancer therapeutic strategy. We previously found a natural product, bouchardatine, modulated aerobic metabolism and inhibited proliferation in the colorectal cancer cell (CRC). Herein, we designed and synthesized a new series of bouchardatine derivatives to discover more potential modulators. We applied the dual-parametric high-content screening (HCS) to evaluate their AMP-activated protein kinase (AMPK) modulation and CRC proliferation inhibition effect simultaneously. And we found their antiproliferation activities were highly correlated to AMPK activation. Among them, 18a was identified with nanomole-level antiproliferation activities against several CRCs. Interestingly, the evaluation found that 18a selectively upregulated oxidative phosphorylation (OXPHOS) and inhibited proliferation by modulating energy metabolism. Additionally, this compound effectively inhibited the RKO xenograft growth along with AMPK activation. In conclusion, our study identified 18a as a promising candidate for CRC treatment and suggested a novel anti-CRC strategy by AMPK activating and OXPHOS upregulating.

[Remodeling midwifery by introducing sterilization in childbirth in the period of Republic of China]

In the period of the Republic of China, the maternal and infant mortality rates were high, most of which were caused by puerperal fever and neonatal tetanus. In this sense, Chinese traditional midwives were often regarded as "dirty". After western obstetrics was introduced into China in the late Qing Dynasty and the early period of the Republic of China,the occurrence of postpartum infection was effectively reduced with childbirth disinfection. To improve the health status of women and infants, the government of the Republic of China put in place measures to develop midwifery. The training of the traditional midwives was included in midwifery education. The delivery basket was used to help promote the new method of delivery and popularise the concept of sterilization of delivery. Thus, midwifery was remodeled and the remodeled midwives played an important role in family midwifery education.

[Comparative study of decompression of unilateral biportal endoscopic compared to laminectomy with fusion and internal fixation in the treatment of severe lumbar spinal stenosis]

Objective: To compare the clinical efficacy of unilateral biportal endoscopy unilateral laminotomy for bilateral decompression (UBE-ULBD) to posterior lumbar interbody fusion (PLIF) in the treatment of severe lumbar spinal stenosis (SLSS). Methods: The clinical data of 64 patients with SLSS treated with PLIF and UBE-ULBD in Dalian Central Hospital Affiliated to Dalian Medical University from April 2018 to April 2021 were collected and divided into UBE group and PLIF group according to the different surgical procedures. There were 30 cases in the UBE group, including 12 males and 18 females, aged (69.8±6.8) years. There were 34 patients in the PLIF group, including 15 males and 19 females, aged (69.3±6.3) years. The operation time, intraoperative blood loss, surgical complications, the volume of drainage, transfusion, post-operative bed rest time, postoperative hospital stay, surgical costs of both groups were recorded and analyzed. The visual analogue scales (VAS) of back/leg pain (pre-operation and 1 d, 1 month, 6 month, 12 month post-operation) and Oswestry disability index (ODI) (pre-operation and 1 month, 6 month, 12 month post-operation) were used to determine the outcome. And the dural sac cross-sectional area (DSCA) and Schizas grade of both groups preoperatively and 6 month postoperatively were recorded. Results: The operation time in the UBE group was (69.2±8.0) min, it was lower than that in the PLIF group (139.0±15.3) min (P<0.05). The intraoperative blood loss and drainage in the UBE group were (19.5±5.6) ml and (15.0±10.8) ml, which were both lower than those in the PILF group [(212.4±34.1) ml and (169.6±43.8) ml] (both P<0.05). The postoperative bed rest time and hospital stay in the UBE group were (1.8±0.7) days and (3.0±0.9) days, which were both shorter than those in the PLIF group [(4.5±1.4) days and (7.1±1.7) days] (both P<0.05). The surgical cost was also lower in the UBE group than that in the PLIF group [RMB,(18.4±1.0) thousands yuan vs (33.9±2.4) thousands yuan, P<0.05]. In addition, no patient received blood transfusion in the UBE group. Dural sac tear occurred in 2 cases in the UBE group and in 3 cases in PLIF group; nerve root injury and infection occurred in one case in the PLIF group, respectively. In the PLIF group, the VAS of back pain was not significantly improved 1 day after operation when compared with that before the operation, but it significantly improved 1 month, 6 months and 1 year after operation (all P<0.05). The VAS for back pain at 1 day after operation and ODI at 1 month after operation in the UBE group were significantly superior to those in the PLIF group (both P<0.05), while there was no significant difference between the two groups in the VAS for back pain at 1 month, 6 months and 1 year after operation and ODI at 6 months and 1 year after operation. Both groups got significant canal expansion after the surgery and the PLIF group showed larger canal expansion extent (all P<0.05). Both groups improved significantly after surgery in the Schizas grade, there were 25 cases in UBE group improved to grade A, 5 cases to grade B while 30 cases in PLIF group improved to grade A, 4 cases to grade B, but there was no significant difference between the two groups (P>0.05). Conclusion: ULBD-UBE could achieve full decompression of the whole spinal canal with limited structures damage in treating SLSS. Compared with PLIF, UBE-ULBD could get complete decompression as well as less iatrogenic damage, it may be an ideal alternative surgical technique for SLSS with less invasion.

[Interpretation of updated guidelines for colorectal cancer screening in average-risk individuals in the United States]

In recent years, due to changes in the epidemiology of colorectal cancer in the United States, the update of evidence-based medical evidence for screening, and the emergence of various new screening methods, various organizations in the United States, such as American College of Gastroenterology、Preventive Services Task Force, have updated guidelines for colorectal cancer screening in average-risk individuals. These guidelines have different recommendation levels in terms of starting and ending age, screening methods and frequency for colorectal cancer screening. A comprehensive understanding of the key points of these guideline updates and the similarities and differences recommended by different guidelines has important reference value for the colorectal cancer screening in China.

Matrine counteracts obesity in mice via inducing adipose thermogenesis by activating HSF1/PGC-1α axis

Promoting energy expenditure is known to curb obesity and can be exploited for its treatment. Our previous study has demonstrated that activation of HSF1/PGC-1α axis efficiently induced mitochondrial biogenesis and adaptive oxidation and thus ameliorating lipid accumulation, however, whether it can be a therapeutic approach for metabolic disorders treatment needs explored. Here, a high-efficient and specific HSF1/PGC-1α activator screening system was established and the natural clinical liver-protecting agent matrine was identified as a robust HSF1/PGC-1α activator. Matrine treatment efficiently induced mitogenesis and thermogenic program in primary mouse adipose stem cell derived adipocytes by enriching HSF1 to the promoter of Pgc-1α. Deficiency of PGC-1α in adipocytes diminished the browning induction ability of matrine. Oral administration of matrine to the obese mice induced by high fat and high cholesterol diet increased energy expenditure and corrected the degeneration of thermogenesis in brown adipose tissue (BAT). Also, matrine treatment markedly induced the transformation of brown-like adipocytes in subcutaneous white adipose tissue (sWAT) via a mechanism of HSF1/PGC-1α, thereby attenuating obesity and myriads of metabolic disorders. This led to an improvement in adaptive thermogenesis to cold stimuli. These findings are of great significance in understanding the regulation mechanisms of the HSF1/PGC-1α axis in thermogenesis and providing a novel therapeutic approach for obesity treatment. Matrine may have potential therapeutic implications for the treatment of obesity in clinics.

Palladium oxidative addition complex-enabled synthesis of amino-substituted indolyl-4(3H)-quinazolinones and their antitumor activity evaluation

The indolyl-4(3H)-quinazolinone core is an important structural motif in functional molecules. However, few methods exist for its direct modification, which limits its potential application. Reported herein is a palladium-mediated amination of halogen-containing indolyl-4(3H)-quinazolinones with a variety of primary and secondary amines via the corresponding palladium oxidative addition complexes. The protocol allows the facile synthesis of indolyl-4(3H)-quinazolinone derivatives with amino groups at all the positions of the benzene ring in moderate to good yields with mild reaction conditions and good functional group tolerance. Furthermore, the antitumor activity of these products was evaluated.

A novel HSF1 activator ameliorates nonalcoholic steatohepatitis by stimulating mitochondrial adaptive oxidation

BACKGROUND AND PURPOSE

Nonalcoholic steatohepatitis (NASH) is the more severe form of metabolic associated fatty liver disease (MAFLD), and no pharmacologic treatment approved as yet. Identification of novel therapeutic targets and their agents are critical to overcome the current inadequacy of drug treatment for NASH.

EXPERIMENTAL APPROACH

The correlation between heat shock factor 1 (HSF1) levels and the development of NASH and the target genes of HSF1 in hepatocyte were revealed by chromatin-immunoprecipitation sequencing. The effects and mechanisms of SYSU-3d in alleviating NASH were examined in relevant cell models and mouse models (the Ob/Ob mice, high-fat and high-cholesterol diet, the methionine-choline deficient diet fed mice). The drug-like properties of SYSU-3d in vivo were evaluated.

KEY RESULTS

HSF1 is progressively reduced with mitochondrial dysfunction in NASH pathogenesis and activation of this transcription factor by its newly-identified activator SYSU-3d efficiently ameliorated all manifestations of NASH in mice. When activated, the phosphorylated HSF1 (Ser326) translocated to nucleus and bound to the promoter of peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) to induce mitochondrial biogenesis, thus increasing mitochondrial adaptive oxidation and inhibiting oxidative stress. The deletion of HSF1 and PGC-1α or recovery of HSF1 in HSF1-deficiency cells revealed the HSF1/PGC-1α metabolic axis mainly responsible for the anti-NASH effects of SYSU-3d independent of adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK).

CONCLUSION AND IMPLICATIONS

Activation of HSF1 is a practicable therapeutic approach for NASH treatment via the HSF1/PGC-1α/mitochondrial axis, and SYSU-3d would take into consideration as a potential candidate for the treatment of NASH.

Direct acceleration of collimated monoenergetic sub-femtosecond electron bunches driven by a radially polarized laser pulse

High-quality ultrashort electron beams have diverse applications in a variety of areas, such as 4D electron diffraction and microscopy, relativistic electron mirrors and ultrashort radiation sources. Direct laser acceleration (DLA) mechanism can produce electron beams with a large amount of charge (several to hundreds of nC), but the generated electron beams usually have large divergence and wide energy spread. Here, we propose a novel DLA scheme to generate high-quality ultrashort electron beams by irradiating a radially polarized laser pulse on a nanofiber. Since electrons are continuously squeezed transversely by the inward radial electric field force, the divergence angle gradually decreases as electrons transport stably with the laser pulse. The well-collimated electron bunches are effectively accelerated by the circularly-symmetric longitudinal electric field and the relative energy spread also gradually decreases. It is demonstrated by three-dimensional (3D) simulations that collimated monoenergetic electron bunches with 0.75° center divergence angle and 14% energy spread can be generated. An analytical model of electron acceleration is presented which interprets well by the 3D simulation results.

The antibacterial effect and physical performance of pit and fissure sealants based on an antibacterial core-shell nanocomposite

The application of pit and fissure sealants is a well-established method to prevent and treat early childhood caries. Resin-based sealants with antibacterial properties provide additional benefits for caries prevention in a cariogenic oral environment. The objective of this study was to evaluate the effect of an antibacterial core-shell AgBr/cationic polymer nanocomposite (AgBr/BHPVP) on the properties of a resin-based pit and fissure sealant. A commercialized pit and fissure sealant without fluoride, Concise (3M, ESPE, USA), was used as the parent material and negative control. Experimental antibacterial sealants were formulated by the addition of AgBr/BHPVP nanoparticles at mass fractions of 0.5, 1.0, and 1.5 wt% to the parent material. A fluoride-releasing sealant, Clinpro (3M, ESPE), was used as the positive control. Bacterial colony-forming unit (CFU) counts, metabolic activity tests, field emission-scanning electron microscopy (FE-SEM), and confocal laser scanning microscopy (CLSM) observations were used to evaluate the antibacterial properties of AgBr/BHPVP-modified sealants against Streptococcus mutans before and after five months of aging. The Vickers microhardness, degree of conversion, and microleakage level of the sealants were also investigated. According to the results of CFU counts and metabolic tests, sealants containing AgBr/BHPVP showed better contact-killing bactericidal activity against S. mutans than the two commercial sealants, irrespective of aging conditions (both P < 0.05). The AgBr/BHPVP-modified sealants also showed a significant inhibitory effect on the planktonic S. mutans around the cured sealant surfaces. In addition, the Vickers microhardness, degree of conversion, and microleakage level of the parent material were not damaged by modification with AgBr/BHPVP (P > 0.05). AgBr/BHPVP-modified pit and fissure sealant with a dual bactericidal mechanism is a promising option for the prevention of pit and fissure caries.

[Effect of postoperative hypoalbuminemia and supplement of human serum albumin on the development of poor wound healing following lumbar internal fixation surgery]

Objective: To analyze the association between postoperative hypoalbuminemia and poor wound healing, and to evaluate whether postoperative supplementation of human serum albumin can improve postoperative wound healing after lumbar internal fixation surgery. Methods: From January 2014 to December 2018, 602 patients who underwent lumbar internal fixation surgery in the Department of Orthopedics, Zhujiang Hostiptal of Southern Medical University were identified. There were 250 males (41.5%) and 352 females (58.5%), with an average age of (60±12) years. All patients' clinical records were reviewed, including demographics data, comorbidity data, preoperative serum laboratory values, intraoperative factor, postoperative serum laboratory values and wound healing, and the incidence rate of poor wound healing was calculated. The statistical analyses were performed with R software and Empower(R) to analyze the factors related to poor wound healing. Multiple logistic regression models were performed with adjustment for the potential confounders to evaluate the effect of postoperative hypoalbuminemia and supplementation of human serum albumin on the development of poor wound healing. Results: Poor wound healing occurred in 51(8.47%) patients. After adjusting for the confounding factors, multiple regression analysis showed that there was no correlation between postoperative albumin levels and poor wound healing(OR=1.00, 95%CI: 0.91-1.10, P=1.000). Compared with patients with postoperative normal albumin level, postoperative hypoalbuminemia would increase the risk of poor wound healing by 13% (OR=1.13, 95%CI: 0.47-2.70, P=0.787). There was no correlation between supplementation of human serum albumin and poor wound healing in patients with normal albumin levels or postoperative hypoalbuminemia (P>0.05). Conclusions: There is no correlation between postoperative hypoalbuminemia and poor wound healing after lumbar internal fixation surgery. Postoperative supplementation of human serum albumin can't improve wound healing.

[Investigation and analysis of 7 cases of acute lung injury caused by a welding operation]

Objective: Throughing the investigation and analysis of seven cases of acute lung injury caused by a welding operation, the hazards and production pathways of harmful gases such as phosgene and nitrogen oxides are understood, which will serve as a reference for preventing similar events in the future. Methods: Throughing the accident scene environment investigation and clinical case analysis, combined with the laboratory test results, carried on the comprehensive analysis. Results: The accident caused a total of 7 people to suffer from acute lung injury to varying degrees. Three of them were sent to the ICU ward for treatment due to acute respiratory failure. After active treatment, 7 people were discharged from the hospital with obvious relief. Conclusion: Welding is also a kind of profession that causes the high incidence of acute lung injury accidents. It is necessary to strengthen the knowledge training and protection awareness education of welding workers to avoid the occurrence of acute harmful gas poisoning accidents.

Bouchardatine analogue alleviates non-alcoholic hepatic fatty liver disease/non-alcoholic steatohepatitis in high-fat fed mice by inhibiting ATP synthase activity

BACKGROUND AND PURPOSE

Non-alcoholic hepatic fatty liver disease (NAFLD) is a manifestation of the metabolic syndrome in the liver and non-alcoholic steatohepatitis (NASH) represents its advanced stage. R17 derived from bouchardatine, shows benefits in the metabolic syndrome, but has not been tested in the liver. The present study examined the pharmacological effects of R17 in a model of NAFLD/NASH and its mode of action.

EXPERIMENTAL APPROACH

The effects of R17 were examined in mice fed a high-fat (HF) diet to induce the pathological characteristics of NAFLD/NASH and in cultures of HuH7 cells. We used histological and immunohistochemical techniques along with western blotting and siRNA. Generation of ROS and apoptosis were measured.

KEY RESULTS

Administration of R17 (20 mg·kg^-1 , i.p. every other day) for 5 weeks reversed HF-induced hepatic triglyceride content, inflammation (inflammatory cytokines and macrophage numbers), injury (hepatocyte ballooning and apoptosis, plasma levels of alanine aminotransferase and aspartate aminotransferase), and fibrogenesis (collagen deposition and mRNA expression of fibrosis markers). In cultured cells, R17 reduced cell steatosis from both lipogenesis and fatty acid influx. The attenuated inflammation and cell injury were associated with inhibition of both endoplasmic reticulum (ER) stress and oxidative stress. Notably, R17 activated the liver kinase B1-AMP-activated protein kinase (AMPK) pathway by inhibiting activity of ATP synthase, rather than direct stimulation of AMPK.

CONCLUSION AND IMPLICATIONS

R17 has therapeutic potential for NAFLD/NASH. Its mode of action involves the elimination of ER and oxidative stresses, possibly via activating the LKB1-AMPK axis by inhibiting the activity of ATP synthase.

Bouchardatine suppresses rectal cancer in mice by disrupting its metabolic pathways via activating the SIRT1-PGC-1α-UCP2 axis

Cancer metabolism is an attractive target of the therapeutic strategy for cancer. The present study identified bouchardatine (Bou) as a potent suppressor of rectal cancer growth by cycle-arresting independent of apoptosis. In cultured HCT-116 rectal cancer cells, Bou increased glucose uptake/oxidation and capacity of mitochondrial oxidation. These effects were associated with an upregulation of uncoupling protein 2 (UCP2) and the activation of its upstream Sirtuin 1 (SIRT1)/(Liver kinase B1) LKB1- (Adenosine monophosphate-activated protein kinase) AMPK axis. The pivotal role of UCP2 in the cancer-suppressing effect was demonstrated by overexpressing UCP2 in HCT-116 cells with similar metabolic effects to those produced by Bou. Interestingly, Bou activated peroxisome proliferators activated receptor γ coactivator 1α (PGC-1α) and recruited it to the promoter of UCP2 in HCT-116 cells along with deacetylation (thus activation) by SIRT1. The requirement of SIRT1 for the cancer-suppressing effect through the PGC-1α-UCP2 was confirmed by the reciprocal responses to Bou in HCT-116 with defected and overexpressed SIRT1. Whereas knockdown, mutation or pharmacological inhibition of SIRT1 all abolished Bou-induced deacetylation/activation of PGC-1α, the opposing effects were observed after overexpressing SIRT1. In mice, administration of Bou (50 mg/kg) also suppressed the growth of rectal cancer associated with increases the UCP2 expression and mitochondria capacity in the tumor. Collectively, our findings suggest that Bou has a therapeutic potential for the treatment of rectal cancer by disrupting the metabolic path of cancer cells via activating the PGC-1α-UCP2 axis with SIRT1 as its primary target.

Design, synthesis and biological evaluation of novel bouchardatine analogs as potential inhibitors of adipogenesis/lipogenesis in 3T3-L1 adipocytes

Inhibition of the differentiation of adipocytes and reduced lipid synthesis are efficacious approaches for treating obesity-related metabolic disorders. Bouchardatine (Bou) is a natural alkaloid that has been reported to moderately inhibit the differentiation of 3T3-L1 cells without inducing toxicity. To explore the importance of aldehyde group at 8a-position of Bou and optimize the activity, we synthesized 35 (31 novel) compounds by discarding or replacing aldehyde group with halogen and introducing different amine chains at 5-position of Bou. The lipid-lowering activity was evaluated using a cell-based screening system. The substitution of the group at the 8a-position of compounds was important for its lipid-lowering activity, and the SAR was discussed. The selective compound 6e showed a 93-fold increase in its lipid-lowering effect (EC₅₀ = 0.24 μM) compared with Bou (EC₅₀ ≈ 25 μM). Further mechanistic studies revealed that compound 6e activated AMP-activated protein kinase (AMPK) pathway and inhibited MCE activity to block cell proliferation and induce cell cycle arrest at the early stage of differentiation, thus decreasing the expression of adipogenic factors and fatty acid synthesis-related proteins.

cDNA cloning and mRNA expression of a tandem-repeat galectin (PoGal2) from the pearl oyster, Pinctada fucata

Galectins can recognize and specifically bind to β-galactoside residues, playing crucial roles in innate immune responses of vertebrates and invertebrates. We cloned the cDNA of a tandem-repeat galectin from the pearl oyster Pinctada fucata (designated as PoGal2). PoGal2 cDNA is 1347 bp long and consists of a 5'-untranslated region (UTR) of 3 bp, a 3'-UTR of 297 bp with one cytokine RNA instability motif (ATTTA), and an open reading frame of 1047 bp, encoding a polypeptide of 349 amino acids, with an estimated molecular mass of 38.1 kDa and a theoretical isoelectric point of 8.5. PoGal2 contains two carbohydrate recognition domains (CRDs); both have the conserved carbohydrate-binding motifs H-NPR and WG-EE. PoGal2 shares 50.6 and 50.9% identity with those of abalone (Haliotis discus) and the Manila clam (Venerupis philippinarum), respectively. Phylogenetic analysis revealed that the tandem-repeat galectins formed two clades for the different species. Molluscan tandem-repeat galectins were clustered into a single clade, and nematode tandem-repeat galectins were clustered into another single clade. In both clades, CRD-N and CRD-C were divided into different groups. PoGal2 mRNA was constitutively expressed in all tissues analyzed, and the expression level of PoGal2 mRNA was found to be significantly up-regulated in digestive glands, gills and hemocytes after Vibrio alginolyticus stimulation/infection. Expression profile analysis showed that the expression level of PoGal2 mRNA was significantly up-regulated at 8, 12 and 24 h after V. alginolyticus infection. These results suggest that PoGal2 is a constitutive and inducible acute-phase protein involved in the innate immune response of pearl oysters.

Estimating surfactant surface coverage and decomposing its effect on drop deformation

A novel method is introduced to estimate surface coverage and the equation of state of insoluble surfactant on droplets, involving measurement of interfacial tension on a single parent drop and progressively subdivided generations of daughter drops. This has enabled quantitative decomposition of the dilution, tip-stretching, and Marangoni effects of surfactants on drop deformation. For a small viscosity ratio of 0.09, the Marangoni effect dominates, increasing first and then decreasing with surface coverage, the dilution effect is significant at high, and tip-stretching only at low surface coverage. For a viscosity ratio of 2.3, the dilution effect dominates, and neither Marangoni nor tip-stretching effects play an important role.

Expression of dominant-negative src-homology domain 2-containing protein tyrosine phosphatase-1 results in increased Syk tyrosine kinase activity and B cell activation

The Src-homology domain 2 (SH2)-containing cytoplasmic tyrosine phosphatase, SHP-1 (SH2-containing protein tyrosine phosphatase-1), interacts with several B cell surface and intracellular signal transduction molecules through its SH2 domains. Mice with the motheaten and viable motheaten mutations are deficient in SHP-1 and lack most mature B cells. To define the role of SHP-1 in mature B cells, we expressed phosphatase-inactive SHP-1 (C453S) in a mature B cell lymphoma line. SHP-1 (C453S) retains the ability to bind to both substrates and appropriate tyrosine-phosphorylated proteins and therefore can compete with the endogenous wild-type enzyme. We found that B cells expressing SHP-1 (C453S) demonstrated enhanced and prolonged tyrosine phosphorylation of proteins with molecular masses of 110, 70, and 55-60 kDa after stimulation with anti-mouse IgG. The tyrosine kinase Syk was hyperphosphorylated and hyperactive in B cells expressing SHP-1 (C453S). SHP-1 and Syk were coimmunoprecipitated from wild-type K46 cells, K46 SHP-1 (C453S) cells, and splenic B cells, and SHP-1 dephosphorylated Syk. Cells expressing SHP-1 (C453S) showed increased Ca2+ mobilization, extracellular signal-regulated kinase activation, and homotypic adhesion after B cell Ag receptor engagement. Thus, SHP-1 regulates multiple early and late events in B lymphocyte activation.

[Effect of sodium suberogorgin on hemodynamics and myocardial ischemic-reperfused injury in isolated guinea pig working hearts]

AIM

To study the actions of sodium suberogorgin (Sub) on normal- and myocardial ischemic-reperfused-working hearts.

METHODS

The isolated guinea pig working hearts were perfused with edetic acid (0.2 mumol.L(-1))-Krebs-Henseleit solution by left pulmonary vein at 37 +/- 0.5 degrees C. The perfusing pressure of left atrium and the afterload of left ventricle were maintained at 1.0 and 7.2 kPa, respectively. During 50-min low-flow global ischemia, coronary flow was maintained at 4.7 +/- 0.2% of normal working hearts via retrograding perfusion. Reperfusion lasted 35 min following ischemia.

RESULTS

Before ischemia, the aortic pressure, left ventricular systolic pressure, the maximal rate of left ventricular pressure change (+ dp/dtmax and -dp/dtmax), cardiac output, stroke volume, left ventricular end-diastolic pressure, and heart rate of working hearts treated with Sub 10 mumol.L(-1) for 10 min were increased by 14%, 17%, 17%, 22%, 15%, 32%, -200%, and -11%, respectively. These parameters were reduced when Sub was increased to 50 mumol.L(-1). Reperfusion aggravated the myocardial damages induced by ischemia. Sub 10 mumol.L(-1) used before and during low-flow ischemia completely restored all above parameters except heart rate to the level of preischemia. When Sub was increased to 50 mumol.L(-1), only an attenuation of myocardial damage was observed.

CONCLUSION

Sub obviously improved the ischemic-reperfused injury in isolated working hearts.

[Excitant effect of sodium suberogorgin on isolated rabbit ileum]

Suberogorgin was isolated from Gorgoniae suberogorgia sp from South China Sea. The isolated rabbit ileum contracted in a concentration-dependent manner by suberogorgin-Na (Sub) 2.13 mumol.L-1 or higher. Sub 213 mumol.L-1 had no effect on the relaxation induced by norepinephrine and isoprenaline 10-100 mumol.L-1 on ileum. The stimulation of Sub on ileum was antagonized by atropine 56 mumol.L-1 or indometacin 0.35 mmol.L-1 and was partly blocked by indometacin 0.17 mmol.L-1, but was not affected by diphenhydramine 10 mumol.L-1. On the contracted ileum induced by neostigmine 1.7 mumol.L-1, acetylcholine 0.1 mumol.L-1 increased the tension but Sub 213 mumolL-1 did not. Sub obviously inhibited the acetylcholinesterase (AChE) from mouse brain hemogenates in vitro. Its pI50 (negative logarithm of molar concentration causing 50% inhibition of AChE) was 4.18, while the pI50 of neostigmine was 4.75. The results indicated that the ileum-excitant action of Sub was chiefly related to the inhibition of AChE.

Prevalence of serological hepatitis B markers in a working population in Hefei, China

Hepatitis B surface antigen and antibody (HBsAg and anti-HBs, respectively) prevalence was examined by means of solid-phase radioimmunoassay in 503 serum samples obtained from factory workers (230 men and 273 women) in Hefei, the capital city of Anhui Province, China, in 1985. The prevalence of HBsAg-positlve cases was 8% and that of anti-HBs-positive cases was 46%; the overall prevalence rate was 53% when the positivity in either of the two was considered to be indicative of hepatitis B virus (HBV) infection. There was no significant sex difference in the rate, whereas anti-HBs rate was slightly elevated in accordance with increased age. The review and evaluation of existing data in 14 articles led to a conclusion that the current HBV prevalence among Chinese populations will be in the range of 50% to 60%.