Complex pathways to cooperation emergent from asymmetry in heterogeneous populations

Cooperation within asymmetric populations has garnered significant attention in evolutionary games. This paper explores cooperation evolution in populations with weak and strong players, using a game model where players choose between cooperation and defection. Asymmetry stems from different benefits for strong and weak cooperators, with their benefit ratio indicating the degree of asymmetry. Varied rankings of parameters including the asymmetry degree, cooperation costs, and benefits brought by weak players give rise to scenarios including the prisoner's dilemma (PDG) for both player types, the snowdrift game (SDG), and mixed PDG-SDG interactions. Our results indicate that in an infinite well-mixed population, defection remains the dominant strategy when strong players engage in the prisoner's dilemma game. However, if strong players play snowdrift games, global cooperation increases with the proportion of strong players. In this scenario, strong cooperators can prevail over strong defectors when the proportion of strong players is low, but the prevalence of cooperation among strong players decreases as their proportion increases. In contrast, within a square lattice, the optimum global cooperation emerges at intermediate proportions of strong players with moderate degrees of asymmetry. Additionally, weak players protect cooperative clusters from exploitation by strong defectors. This study highlights the complex dynamics of cooperation in asymmetric interactions, contributing to the theory of cooperation in asymmetric games.

Facilitating cooperation in human-agent hybrid populations through autonomous agents

Cooperative AI has shown its effectiveness in solving the conundrum of cooperation. Understanding how cooperation emerges in human-agent hybrid populations is a topic of significant interest, particularly in the realm of evolutionary game theory. In this article, we scrutinize how cooperative and defective Autonomous Agents (AAs) influence human cooperation in social dilemma games with a one-shot setting. Focusing on well-mixed populations, we find that cooperative AAs have a limited impact in the prisoner's dilemma games but facilitate cooperation in the stag hunt games. Surprisingly, defective AAs can promote complete dominance of cooperation in the snowdrift games. As the proportion of AAs increases, both cooperative and defective AAs have the potential to cause human cooperation to disappear. We then extend our investigation to consider the pairwise comparison rule and complex networks, elucidating that imitation strength and population structure are critical for the emergence of human cooperation in human-agent hybrid populations.

Molecular mechanisms revealed by network pharmacology of Xuebijing on the treatment of acute respiratory distress syndrome caused by novel coronavirus infection

OBJECTIVE

The study aims to predict the target and molecular mechanism of Xuebijing injection in the treatment of novel coronavirus-induced acute respiratory distress syndrome (ARDS), based on network pharmacology.

MATERIALS AND METHODS

Chinese and English studies were searched to obtain the main active components of Xuebijing injection. ETCM, TCMSP and Targetnet online databases were adopted used to predict Xuebijing therapeutic targets. GeneCards, CTD and OMIM databases were researched used to research for the novel coronavirus Disease-2019 (COVID-19) and ARDS-related targets. Integrate analysis was carried out to obtain the targets of Xuebijing injection in the treatment of ARDS caused by novel coronavirus. STRING was adopted to analyze the interaction of common target proteins. GO and KEGG enrichment analyses were carried out using Bioconductor bioinformatics software package based on R software. Network visualization was performed with Cytoscape software.

RESULTS

A total of 30 main active components in Xuebijing injection were collected in this study, which can act on 615 targets. The core components of Xuebijing injection in treating the coronavirus-induced ARDS are Ferulic acid, Ethyl ferulate, Albiflorin, Caffeic acid, Rosmarinic acid, Naringenin, Quercetin. Xuebijing injection has 56 target points for the treatment of ARDS caused by the novel coronavirus, among which AKT1, TNF, CASP3 and STAT3 are the core ones. The main molecular mechanisms of Xuebijing injection in treating the coronavirus-induced ARDs include PI3K-Akt, TNF, STAT3, NF-κB and apoptosis-related pathways.

CONCLUSIONS

Xuebijing mainly treats ARDS caused by the novel coronavirus through anti-inflammation, anti-apoptosis, and regulation of immunity since it has the characteristics of multi-component, multi-target and multi-pathway.

[Study of the association between polymorphism of persistent obesity, human leptin gene/leptin receptor gene and molecular subtypes of breast cancer]

Objectives: To explore the association between the polymorphism of persistent obesity and genetic variations in the LEP (human leptin gene, LEP) and LEPR (leptin receptor gene, LEPR) genes and different molecular subtypes of breast cancer. Methods: All 703 female patients of breast cancer diagnosed by histopathology in the Sichuan Cancer Hospital or the West China Hospital, excluding patients with metastatic breast cancer or mental disease, were selected as cases from April 2014 to May 2015. At the same time, 805 healthy women received physical examination in medical examination center of Sichuan People Hospital or Shuangliu maternal and child health care hospital, excluding those with therioma, breast disease, and mental disease, were enrolled in control group. A uniform questionnaire was used to collect general information including demographic characteristic, reproductive history height, weight, and so on. And the obesity status in recent 10 years was judged. Time of Flight Mass Spectrometer was used to determine the genotypes of LEP rs7799039, LEPR rs1137100 and LEPR rs1137101, while the multinomial logistic regression analysis was conducted to estimate the effect of risk factors related to breast cancer in different molecular subtypes; and then, the association between polymorphism of persistent obesity, the LEP, LEPR genes and breast cancer of different molecular subtypes was analyzed by binary logistic regression models. Results: The average age of controls was (48.98±8.83) years old, while the age of cases of TNBC, Luminal A, Luminal B, and HER-2+ were (51.43±11.33), (49.94±10.10), (49.73±9.38), (50.50±9.04) years old, respectively. The frequency of genotype LEP rs7799039, LEPR rs1137100 and LEPR rs1137101 in control group was separately 74.8%(1 157/1 546), 83.6%(1 339/1 602) and 88.4%(1 416/1 602); while 77.6% (1 074/1 384), 82.4% (1 155/1 402) and 87.9% (1 232/1 402) respectively in case group. Compared with non-persistent obesity subjects, the persistent obesity ones showed an increased risk in TNBC (OR=3.58, 95%CI: 1.90-6.72), Luminal A (OR=2.65, 95%CI: 1.35-5.21) and Luminal B (OR=1.90, 95%CI: 1.26-2.89) breast cancer. LEP rs7799039-AA was relevant with the upward risk of Luminal B independently (OR=1.30, 95%CI: 1.00-1.69). Besides, persistent obesity was found to have a combined effect on Luminal B (β=3.34, 95% CI: 1.00-11.12) with LEPR rs1137101-GG. Conclusion: Persistent obesity could increase the potential risk of TNBC, Luminal A and Luminal B breast cancer. Women who were suffered from persistent obesity with a genotype of LEPR rs1137101-GG were more susceptible to Luminal B breast cancer.

[Hypopharyngeal angiofibroma: a case report]

Swallowing obstruction, gradually increase, with a sore throat, no fever, no haemoptysis, no dyspnea, routine tests: blood routine, biochemical examination, blood coagulation routine, electrocardiogram, chest X-ray, did not show abnormalities.

Genome-wide identification, classification, and analysis of heat shock transcription factor family in Chinese cabbage (Brassica rapa pekinensis)

Chinese cabbage (Brassica rapa ssp. pekinensis) is one of the most important vegetable crops grown worldwide, and various methods exist for selection, propagation, and cultivation. The entire Chinese cabbage genome has been sequenced, and the heat shock transcription factor family (Hsfs) has been found to play a central role in plant growth and development and in the response to biotic and abiotic stress conditions, particularly in acquired thermotolerance. We analyzed heat tolerance mechanisms in Chinese cabbage. In this study, 30 Hsfs were identified from the Chinese cabbage genome database. The classification, phylogenetic reconstruction, chromosome distribution, conserved motifs, expression analysis, and interaction networks of the Hsfs were predicted and analyzed. Thirty BrHsfs were classified into 3 major classes (class A, B, and C) according to their structural characteristics and phylogenetic comparisons, and class A was further subdivided into 8 subclasses. Distribution mapping results showed that Hsf genes were located on 10 Chinese cabbage chromosomes. The expression profile indicated that Hsfs play differential roles in 5 organs in Chinese cabbage, and likely participate in the development of underground parts and regulation of reproductive growth. An orthologous gene interaction network was constructed, and included MBF1C, ROF1, TBP2, CDC2, and HSP70 5 genes, which are closely related to heat stress. Our results contribute to the understanding of the complexity of Hsfs in Chinese cabbage and provide a basis for further functional gene research.

Chemiluminescent Probes for Imaging H2S in Living Animals

Hydrogen sulphide (H2S) is an endogenous mediator of human health and disease, but precise measurement in living cells and animals remains a considerable challenge. We report the total chemical synthesis and characterization of three 1,2-dioxetane chemiluminescent reaction-based H2S probes, CHS-1, CHS-2, and CHS-3. Upon treatment with H2S at physiological pH, these probes display instantaneous light emission that is sustained for over an hour with high selectivity against other reactive sulphur, oxygen, and nitrogen species. Analysis of the phenol/phenolate equilibrium and atomic charges has provided a generally applicable predictive model to design improved chemiluminescent probes. The utility of these chemiluminescent reagents was demonstrated by applying CHS-3 to detect cellularly generated H2S using a multi-well plate reader and to image H2S in living mice using CCD camera technology.

Purification and Characterization of a 4-Hydroxybenzoate Decarboxylase from Chlamydophila pneumoniae AR39

Chlamydophila pneumoniae AR39 is an obligate intracellular pathogen that causes human acute and chronic respiratory tract diseases. One protein from C. pneumoniae AR39 was assigned as 4-hydroxybenzoate decarboxylase (HBDC). Assays done with the purified oxygen-sensitive protein showed that the optimum pH and temperature were 7.5 and 30 degrees C, respectively. The Km and Vmax obtained for 4-hydroxybenzoate were approximately 0.21 mM and 11.9 nM min(-1) mg(-1), respectively. During the period of 4-hydroxybenzoate decarboxylation, overall activity of the thermal-sensitive protein was 5.06 nM min(-1) mg(-1) protein. The 4-hydroxybenzoate decarboxylation was promoted by Mg(2+), Fe(2+), Mn(2+), and Ca(2+) but not by Cu(2+) or Zn(2+). The enzyme also slowly catalyzed the reverse reaction, which was phenol carboxylation.

[Hip ambulatory abduction in the treatment of Legg-Calve-Perthes disease]

Forty-eight cases of Legg-Calve-Perthes disease were treated with hip ambulatory abduction brace. The children were able to walk, sit, climb, or squat with the brace. Thirty-nine cases were followed up more than three years. The total excellent rate was 82%. The result of Catterall Grade I-II cases was all excellent. The excellent rate was 80% below five-year-old cases of Catterall III-IV during the start of the treatment and 66.6% above five. With the active hip abduction and internal rotation, the femoral head was held well. The results show that the method is simple and with no operation and with satisfactory effect of the treatment.

[Anti-hepatitis B virus effects of lamivudine and other five drugs in vitro]

OBJECTIVE

To find out reliable index for evaluating the anti-hepatitis B virus (HBV) effects in vitro of lamivudine (3TC) and other five anti-HBV drugs.

METHODS

The contents of human hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg) and hepatitis B virus DNA (HBV DNA) in the culture supernatant of 2.2.15 cell line transfected with hepatitis B virus gene were tested after the six anti-hepatitis B virus drugs were added respectively, and the accordance of different indexes was compared.

RESULTS

All six drugs, within a certain range, exercised only weak or no inhibitive effect on extracellular HBsAg and HBeAg secreted by 2.2.15 cell line. Lamivudine and 2 3-dideoxy-3-fluoroguanosine (FLG) significantly inhibited the level of HBV DNA, with the 50% inhibition concentration(IC50) of 0.31 mumol/L and 0.53 mumol/L respectively. Acyclovir (ACV) and interferon-alpha(IFN-alpha) also inhibited the HBV DNA with the IC50 of 0.33 mmol/L and 96.18 U/ml respectively. Phosphonoformate (PFA) and ribavirin (RBV) showed none effect on HBV DNA content even at the maximum non-toxic concentrations.

CONCLUSION

There is not accordance between the expression activities of proteins of HBsAg and HBeAg and the inhibition of HBV DNA level. HBV DNA level better reflexes the inhibitive effect of different drugs and can be used as an important index for evaluation of anti-HBV effect in vitro.

[Bronchial arterial infusion chemotherapy in the treatment of stage III non-small cell lung cancer]

BACKGROUND

To explore the methods of comprehensive treatment of stage III non-small cell lung cancer ( NSCLC) .

METHODS

Treating group consisting of fifty patients with stage III NSCLC was treated with interventional chemotherapy, surgical treatment and radiotherapy, and 42 patients as control.

RESULTS

Resection rate in treating group was 94. 0% after interventional chemotherapy, and 84. 0% of the group got radical resection. The 1-, 3-, 5-year survival rates were 44. 0%, 36. 0%, and 22. 0% in the treating group, and were 23. 8%, 16. 7% and 7. 1% respectively in control group ( P < 0. 05) .

CONCLUSIONS

Standard comprehensive treatment is helpful to improve curative effect of stage III NSCLC.

Protein ligand docking based on empirical method for binding affinity estimation

An empirical protein-ligand binding affinity estimation method, SCORE, was incorporated into a popular docking program, DOCK4. The combined program, ScoreDock, was used to reconstruct the 200 protein-ligand complex structures and found to give good results for the complexes with high binding affinities. A quality assessment method for docking results from ScoreDock was developed based on the whole test set and tested by additionally selected complexes. The method significantly improves the docking accuracy and was shown to be reliable in docking quality assessment. As a docking tool in structural based drug design, ScoreDock can screen out final hits directly based on the predicted negative logarithms of dissociation equilibrium constants of protein-ligand complexes, and can explicitly deal with structure water molecules, as well as metal atoms.

Antiviral activity of mixed-valence rare earth borotungstate heteropoly blues against influenza virus in mice

The acute and accumulated toxicity of the rare earth borotungstate heteropoly blues, HPB-2, Ce2H3[BW9(VI)W2(V)Mn(H2O)O39].12H2O, which is active against influenza virus in Kunming mice, were investigated in Kunming mice following oral and intraperitoneal administration. The activity of HPB-2 against influenza virus (FM1) in the mice was then investigated. HPB-2, given either orally (p.o.) or intraperitoneally (i.p.), was shown to have activity. HPB-2 was shown to be more effective than the positive control, ribavirin, and it was also found that i.p. administration was more effective than p.o. administration.

[Selective inhibition of HSV-1 DNA and protein synthesis by antiviral antibiotic 17997]

OBJECTIVE

To study the effects of 17997 on the HSV-1 DNA and protein synthesis.

METHODS

DNA synthesis was determined by isopycnic separation of cellular and viral DNA in CsCl gradients centrifugation. Protein synthesis was determined by SDS-PAGE and Western blot.

RESULTS

The inhibition rates of 0.5 micromol/L, 1.0 micromol/L, 2.0 micromol/L and 4.0 micromol/L of 17997 on HSV-1 DNA synthesis were 63.1%,74. 1%, 93.9% and 100%, respectively. 4.0 micromol/L of 17997 did not inhibit VERO cell DNA synthesis. The above concentrations of 17997 did not show any inhibitory effects on cellular protein synthesis, but selectively inhibited on viral protein synthesis.

CONCLUSIONS

17997 selectively displayed inhibitive effects on HSV-1 DNA and protein synthesis.

[The efficacy of antiviral antibiotic 17997 on treatment of HSV-1 infected guinea pig skin infection]

OBJECTIVE

To study the treatment efficacy of antiviral antibiotic 17997 against HSVl infected guinea pig skin infection.

METHODS

Guinea pig skin was infected by HSV1. 24hrs or 48hrs of post infection local treatment of 0.3% 17997 cream was started, tid for five days. In the mean time, acyclovir treatment, cream treatment and virus control were included.

RESULTS

Local treatment of 0.3% 17997 cream showed therapeutic effects, it reduced the average scores of skin lesion, accelerated crusting-time and healing-time.

CONCLUSIONS

0.3% 17997 cream showed significant treatment efficacy when compared with cream and virus controls by reducing skin lesion scores and healing-time. The treatment efficacy of 3.0% acyclovir cream was a little bit better than 0.3% 17997 cream.

Proteoglycan (aggrecan)-induced arthritis in BALB/c mice is a Th1-type disease regulated by Th2 cytokines

In animal models of arthritis induced with Ags or infectious agents, disease severity correlates with a dominant Th1-type response characterized by a higher ratio of IFN-gamma to IL-4. Analysis of BALB/c mice revealed a genetic predisposition toward developing CD4+ Th2-type responses. The bias toward an IL-4-dominant response in BALB/c mice protects mice from severe Lyme-induced arthritis and spontaneous autoimmune disease. Since BALB/c mice immunized with proteoglycan develop severe arthritis, we were interested in testing whether arthritis is associated with a Th2-type response and thus is different from other arthritic models. BALB/c mice immunized with proteoglycan generated a higher ratio of IFN-gamma to IL-4 that peaks at the onset of arthritis. We investigated whether when Th1 cells were dominant, disease outcome could be modified with pharmacological amounts of Th2 cytokines. Treatment with IL-4 prevented disease and induced a switch from a Th1-type to a Th2-type response. Proinflammatory cytokine mRNA transcripts were reduced in joints of cytokine-treated mice. Th2 cytokine therapy at the time of maximum joint inflammation also suppressed symptoms of disease. Despite the predisposition of BALB/c mice to a Th2-type response, proteoglycan-induced arthritis is a Th1-type disease. The effectiveness of IL-4 treatment was particularly striking because in other models of arthritis, treatment in a similar manner with IL-4 was not sufficient to inhibit arthritis. The effective control of arthritis and the switch from a Th1 to Th2 response suggest that levels of endogenous IL-4 in BALB/c mice may increase their responsiveness to Th2 cytokine therapy.

Changes in frequency of HIV-1-specific cytotoxic T cell precursors and circulating effectors after combination antiretroviral therapy in children

Combination antiretroviral therapy has had a major role in reducing human immunodeficiency virus type 1 (HIV-1) plasma viral loads in HIV-1-infected adults but a variable effect in infants, in whom complete viral suppression appears to be less readily achieved. In adults, after the reduction in plasma viremia, there is a decrease in the numbers of circulating cytotoxic T cell (CTL) effectors and precursors in the majority of patients. This longitudinal study assessed the effect of combination drug therapy on the frequency of HIV-1-specific CTL responses in 8 HIV-1-infected children. Following treatment, the frequency of HIV-1-specific CTL responses initially increased, especially in children with incomplete viral suppression but with increasing CD4+ cell counts. In children with complete viral suppression, the frequency of HIV-1-specific CTL responses decreased, suggesting that viral replication is required to maintain CTL responses in the systemic circulation.

[Establishment of a microbial assay for screening anti-human immunodeficiency virus type-1 protease inhibitors]

OBJECTIVE

This study was to establish a microbial assay of human immunodeficiency virus type-1 protease (HIV-1 PR) activity for screening anti-HIV PR inhibitors.

METHODS

A 24 bp synthetic oligonucleotide fragment that encodes the HIV-1 PR recognition sequence was inserted into the tetr gene of pBR322 (mtetr). Escherichia coli containing HIV-1 PR expression vector-pPOLO was transformed with pACYC184M containing modified mtetr gene. The transformant could express both HIV-1 PR and the modified Tet protein.

RESULTS

The growth of engineered E. coli was prevented in the presence of tetracycline because the resistance Tet protein was degraded by HIV-1 PR. However inhibition of the HIV-1 PR restored tetracycline resistance. 31 chemical synthetic compounds were tested by the microbial assay.

CONCLUSIONS

A microbial assay method of HIV-1 PR activity was established through a engineered E. coli. 5 mumol/L saqunavir-a special HIV-1 PR inhibitor showed inhibitory effect on the engineered E. coli. That means this model could be used as a initial screening model for anti-HIV PR agents.

[The study on purification and characterization of HIV-1 reverse transcriptase from a recombinant strain of E. coli]

Of the HIV proteins, reverse transcriptase(RT) has been probably the most useful target protein for screening and designing of its specific inhibitors. Because retroviral replication is absolutely dependent on both the RNase H and the polymerase function of RT and, so far as is now known, RT does not play a direct role in the life cycle of a normal cell. Under suitable fermentation conditions in our experiments, HIV-1 RT was highly expressed in E. coli JM109(pKRT-2)* by inducing the trc promoter with isopropyl-beta-Dthiogalactopyranoside(IPTG). 1. 1 mg of purified RT was obtained from one liter culture of bacteria by DEAE-cellulose and phosphaellulose chromatography. SDS-PAGE analysis of the purified RT showed two major protein bands of 66 kD and 51 kD, indicating that the purified RT was a heterodimer composed of two subunits. Results of enzyme assay showed that the purified RT had high activity(1.4 x 10(4) umit/mg). We also improved the reaction system of enzyme assay. The effect of PFA on HIV-1 RT was determined with the improved enzyme assay and the mechanism of inhibition was non-competitive with respect to substrate consistent with the reports of Dr. Bo Oberg. This suggests that the purified HIV-1 RT by this simple method can be applied to the anti HIV-1-drug screening. (*E. coli JM109(pKRT2) was obtained from NIAID, NIH; pKRT2 from Dr. Richard D'Aquila and Dr. William C. Summers.)

[Effects of 5-HT on activity of arcuate neurons of rat hypothalamic slices]

Extracellular recordings were made from 176 spontaneous discharging units in the arcuate nucleus of rat hypothalamic slices. Depending on the patterns of discharge, the units were divided into three types; slow irregular (76%), fast continuous (26.5%) and phasic units (6.3%). The effect of 5-HT on the different types of units were observed. The results indicated that most of neurons were inhibited by 5-HT, and only a small portion of the cells showed excitation and a few of the slow irregular units showed "excitation after inhibition". With 5-HT 10(-6) mol/L we found that 12 units inhibited by 5-HT could not be reversed by CHD, while the 4 inhibited units could be partly or completely reversed by MSG. 4 of the 7 neurons inhibited by 5-HT were partly blocked by Pindobind-5-HT1A but not for the remaining 3 neurons. The results suggest that the inhibitory effect of 5-HT on arcuate neurons may be mediated by 5-HT1 receptor, while some by 5-HT1A receptor.

A novel detection assay for the early diagnosis of HIV-1 infected infants

This investigation compares the results of a new method of diagnosing HIV-1 infection in infants < 6 months of age with currently employed techniques including cocultivation, the polymerase chain reaction (PCR), serum p24 antigen, and in vitro antibody production (IVAP) measurements. The new method, called in vitro antigen (IVAG), measures p24 antigen released into culture supernatants of peripheral blood mononuclear cells that are incubated with Epstein-Barr virus (EBV). No activated donor lymphocytes or interleukin 2 (IL-2) are added to the culture. Using this technique, HIV-1 infection was detected in 15 of 17 HIV-1-infected infants < 2 months of age, including 3 of 7 infants tested at birth, and 15 of 15 HIV-1-infected infants between 2 and 6 months of age. None of 83 determinations of 15 uninfected infants were positive. These results were found to be comparable to results obtained by the traditional cocultivation technique and the polymerase chain reaction. Because of its simplicity and reduced cost, this sensitive and specific assay could be a valuable addition to the current methods of diagnosis of HIV-1 infection in young infants.

[Isolation and characterization of mutactimycin-producing mutant]

Natural non-antibiotic producing Streptomyces sp. 1254 was mutagenized by UV irradiation and two active mutants were isolated. Mutant 113 produced novel anthracycline compounds designated mutactimycins. Mutactimycin A was active against the bacteriophage of Bac. subtilis and some viruses in tissue culture. The mutant 2-6 synthesized a basic water-soluble antimicrobial antibiotic. Chemical analysis of the whole cell hydrolysate and the morphological characterization showed that the strain 1254 and its mutant 2-6 were of chemotype I, belonging to the genus of Streptomyces, and the mutant 113 was of chemotype IV without mycolic acid. Co-synthesis test of strain 1254 and a blocked mutant of strain 113 gave the active compounds identical with mutactimycins. Using the actI gene as a probe, the Southern hybridization revealed homology between the actinorhodin polyketide biosynthase gene and the total DNA of the strain 1254. Based on these data it was deduced that Streptomyces sp. 1254 should have a biosynthesis pathway for mutactimycin, but some of its genes might fail in expression and mutagenesis would make the silent gene(s) active.

[The inhibitory effects of catechin derivatives on the activities of human immunodeficiency virus reverse transcriptase and DNA polymerases]

Catechin derivatives including (-)-epicatechin gallate (ECG), (-)-epigallocatechin gallate (EGCG), (-)-epigallocatechin (EGC) and green tea extract (GTE) were found to inhibit the activities of cloned human immunodeficiency virus type 1 reverse transcriptase (HIV-1 RT), duck hepatitis B virus replication complexes reverse transcriptase (DHBV RCs RT), herpes simplex virus 1 DNA polymerase (HSV-1 DNAP) and cow thymus DNA polymerase alpha (CT DNAP alpha). EGCG and ECG were shown to be very potent inhibitors of HIV-1 RT. According to the IC50 values for HIV-1 RT, these compounds can be ordered as EGCG 0.0066 mumol/L > ECG 0.084 mumol/L > GTE 0.1 microgram/ml > EGC 7.2 mumol/L. DHBV RCs RT was the least sensitive to these compounds. Kinetic study showed that EGCG exerts a mixed inhibition with respect to external template inducer poly (rA).oligo (dT) 12-18 and a noncompetitive inhibition with respect to substrate dTTP for HIV-1 RT. Bovine serum albumin significantly reduced the inhibitory effects of catechin analogues and GTE on HIV-1 RT. In tissue culture GTE inhibited the cytopathic effect of coxsackie B3 virus, but did not inhibit the cytopathic effects of HSV-1, HSV-2, influenza A or influenza B viruses.

Intravenous recombinant tissue-type plasminogen activator in acute myocardial infarction

The efficacy and safety of intravenously administered recombinant tissue-type plasminogen activator (rt-PA, Boehringer Ingelheim Corp.) was investigated in 10 patients with acute myocardial infarction (AMI). rt-PA was given as a 10 mg bolus dose followed by infusions of 50 mg, 20 mg and 20 mg in three successive hours. All patients underwent baseline coronary angiography before thrombolytic therapy. Ninety minutes after the initiation of rt-PA infusion, recanalization of infarct-related coronary arteries as confirmed by angiography was achieved in 7 patients. The largest reduction in circulating fibrinogen was observed 4 to 6 h after the start of rt-PA infusion--14.3%. Moderate hemorrhage at the sites of arterial puncture occurred in 2 cases, probably as a result of heparin anticoagulation. No other side effects occurred. So rt-PA is an effective and safe thrombolytic agent.

Diagnosis of tertian malaria by enzyme-linked immunosorbent assay

A method of ELISA diagnosis of tertian malaria based on detecting Plasmodium vivax antigen in red blood cells (RBC) was developed, using 0.16 ml of packed, washed, and sonicated RBC. 68 blood samples from tertian malaria cases were examined; 67 (98.5%) were positive. 104 normal persons were all negative by this test. The lowest parasite number detected was 3 parasites/10(5) RBC on a thin film, or 1-2 parasites per thick film of usual size.

Effects of prostaglandin E2, 16,16-dimethyl prostaglandin E2 and a prostaglandin endoperoxide analogue (U-46619) on gastric secretory volume, [H+] and mucus synthesis and secretion in the rat

The effects of orally administered prostaglandin E2, 16,16-dimethyl prostaglandin E2 and U-46619, an analogue of the prostaglandin endoperoxide PGH2, on gastric secretory volume, acid and mucus were studied in the rat. All of the compounds significantly increased the volume of gastric secretion, mucus secretion, measured as N-acetylneuraminic acid and mucus synthesis measured as the incorporation of [3H]-glucosamine into mucosal glycoprotein; however, only PGE2 and 16,16-dimethyl PGE2 inhibited acid secretion. U-46619, 1.5 mg/kg provided significant protection against ethanol-induced gastric ulcers, an effect that has been previously shown for the other two compounds. These studies provide additional evidence that prostaglandin induced mucosal protection may be related to an effect on mucus and on stimulation of nonparietal cell gastric secretion. Further study of these parameters may be important in the development of antiulcer drugs for long term clinical use.

The effects of a prostaglandin endoperoxide analogue on canine gastric acid and mucus secretion

The effects of U-46619, a stable analogue of the prostaglandin endoperoxide PGH2, were studied on canine gastric acid secretion, gastric mucosal blood flow, and secretion of mucus into gastric juice and compared to those of PGE2. U-46619 was approximately four and three times as potent as PGE2 in inhibiting acid secretion and stimulating mucus secretion, respectively. When infused at a low dose, U-46619 inhibited acid secretion directly without causing a decrease in the ratio of mucosal blood flow to volume rate of secretion (R), this effect being similar to that observed for PGE2. However, unlike PGE2, U-46619 when administered in a higher dose caused a decline in R while decreasing acid secretion and mucosal blood flow, suggesting a primary restriction of blood flow. The antisecretory effects of arachidonic acid may be due in part to the endogenous formation of prostaglandin endoperoxides as opposed solely to prostaglandin formation. Considering the antisecretory and mucogenic actions of U-46619, nontoxic analogues of prostaglandin endoperoxides may be of value as antiulcer agents.

Cyclic nucleotides and the regulation of canine gastric acid secretion

The response of the cyclic nucleotide system (cAMP, cGMP, adenylate cyclase, guanylate cyclase, and specific phosphodiesterases) to two gastric acid secretagogues, histamine and acetylcholine, and two secretory inhibitors, prostaglandin E2 and secretin, was studied in vivo and in vitro in canine gastric fundic mucosa. Histamine and acetylcholine in vivo failed to stimulate cAMP but significantly increased cGMP; in vitro they affected neither adenylate cyclase nor guanylate cyclase. Prostaglandin E2 and secretin, however, increased cAMP in vivo and significantly stimulated adenylate cyclase in vitro. Specific phosphodiesterases were unaffected by these compounds. The changes, while not specifically localized to the acid-producing cells, are consistent with the suggestion that the control of canine gastric acid secretion may be mediated by changes in mucosal cAMP and cGMP.

Effects of indomethacin on intestinal secretion, prostaglandin E and cyclic AMP: evidence against a role for prostaglandins in cholera toxin-induced secretion

The effects of indomethacin on intestine mucosal cAMP, intestinal fluid secretion, and mucosal and fluid PGE were studied in rabbits in vivo following challenge with cholera toxin. Indomethacin had no effect on cholera toxin-induced fluid secretion or cAMP accumulation. Inhibition of PGE synthesis was achieved by the administration of two but not one injection of indomethacin. These studies provide evidence against a role for PGE in mediating cholera toxin-induced secretion and point out the need to measure prostaglandin levels when using prostaglandin synthetase inhibitors in vivo.

Effects of an orally administered prostaglandin analogue (16, 16-dimethyl prostaglandin E2) on human gastric secretion

The secretory response to 16, 16-dimethyl prostaglandin E2 (DMPG) administered orally in 4 different dosages and to placebo was evaluated in healthy volunteers over a 2-hr period. During stimulation of gastric secretion by histamine, DMPG at the highest dosage (1.5 mug per kg) reduced volume by 47% and acid output by 79%. Pepsin concentration was not affected. At the same dose, DMPG inhibited basal secretion by 54% and 99% for volume and acid output, respectively. There were no side effects secondary to DMPG administration, which indicates that this compound may be useful in treating peptic ulcer disease.

Action of Escherichia coli enterotoxin: adenylate cyclase behavior of intestinal epithelial cells in culture

Heat-labile enterotoxin preparations obtained from two enteropathogenic strains of Escherichia coli of porcine and human origin were shown to stimulate adenylate cyclase activity of human embryonic intestinal epithelial cells in culture. Comparable results were also obtained when cholera toxin was used. The degree of enzyme stimulation was proportional to the concentration of enterotoxin. Similar preparations from two strains of non-enterotoxigenic E. coli had no effect on adenylate cyclase activity. Cells exposed to enterotoxin could be washed after 1 min of contact time without altering the subsequent course of maximum adenylate cyclase activity, which was maintained for at least 18 h at 37 C. During long periods (18 h) of tissue culture incubation, the determination of adenylate cyclase activity was 200- to 300-fold more sensitive than quantitating fluid accumulation in the adult rabbit ileal loop model. Decreasing the incubation time appreciably reduced the sensitivity of the epithelial cells to enterotoxin. E. coli enterotoxin is an effective activator of nonintestinal adenylate cyclase systems. Treatment of KB and HEp-2 cell lines with enterotoxin also resulted in significant enzyme stimulation. The intestinal epithelial cell tissue culture model provides a sensitive homogenous biological system for studying the response of intestinal adenylate cyclase to enterotoxin while eliminating the numerous cellular and tissue components present in the ligated ileal loop model.

Kinetic evidence for the presence of two prostaglandin receptor sites regulating the activity of intestinal adenylate cyclase sensitive to Escherichia coli enterotoxin

Kinetic behavior most consistent with the presence of two independent, but simultaneously acting, regulatory effector sites for prostaglandins has been presented for adenylate cyclase (EC 4.6.1.1) of rabbit intestinal epithelial cells. One site regulates activation of the catalytic site, while the other site regulates inhibition. A synthetic prostaglandin analogue, 7-oxa-13-prostynoic acid, is recognized at both sites in a concentration-dependent manner. At concentrations of 7-oxa-13-prostynoic acid less than 45 mug/ml, activation is seen, while at higher concentrations, inhibition is seen. Different naturally occurring prostaglandins appear to be site-specific. Prostaglandin E(1) gives only activation of the cyclase, while prostaglandin A(1) gives only inhibition of the activated cyclase. When saturating concentrations of prostaglandin E(1) are used to activate adenylate cyclase, no further activation by 7-oxa-13-prostynoic acid can be elicited, indicating that both molecules activate at the same site. The similarity of inhibition constants for both 7-oxa-13-prostynoic acid and prostaglandin A(1) suggests that the mode of binding is the same for both compounds and that they probably inhibit by acting at the same site. The inhibition by 7-oxa-13-prostynoic acid and by prostaglandin A(1) overrides enzyme activation produced by either Escherichia coli enterotoxin, prostaglandin E(1), or sodium fluoride, suggesting that in intestinal adenylate cyclase this site is the primary regulatory site (i.e., primary allosteric effector site) for enzyme activity. These data suggest that sites exist on adenylate cyclase which would allow prostaglandins to serve as the intracellular messengers by which the cell controls its adenylate-cyclase-mediated response to extracellular stimulation, as with hormones.