Triggering apoptosis in cancer cells with an analogue of cribrostatin 6 that elevates intracellular ROS.

Elevation of reactive oxygen species (ROS) is both a consequence and driver of the upregulated metabolism and proliferation of transformed cells. The resulting increase in oxidative stress is postulated to saturate the cellular antioxidant machinery, leaving cancer cells susceptible to agents that further elevate their intracellular oxidative stress. Several small molecules, including the marine natural product cribrostatin 6, have been demonstrated to trigger apoptosis in cancer cells by increasing intracellular ROS. Here, we report the modular synthesis of a series of cribrostatin 6 derivatives, and assessment of their activity in a number of cell lines. We establish that placing a phenyl ring on carbon 8 of cribrostatin 6 leads to increased potency, and observe a window of selectivity towards cancer cells. The mechanism of activity of this more potent analogue is assessed and demonstrated to induce apoptosis in cancer cells by increasing ROS. Our results demonstrate the potential for targeting tumors with molecules that enhance intracellular oxidative stress.

Epidemiology of human infections with avian influenza A(H7N9) virus in the two waves before and after October 2013 in Zhejiang province, China.

We compared the epidemiological and clinical features of avian influenza A(H7N9) virus infections in the population in Zhejiang province, China, between March and April 2013 (first wave) and October 2013 and February 2014 (second wave). No statistical difference was found for age, sex, occupation, presence of underlying conditions, exposure history, white blood cell count, lymphocyte percentage and illness timeline and duration (all P > 0.05). The virus spread to 30 new counties compared to the first wave. The case-fatality rate was 22% in the first wave and 42% in the second (P = 0.023). Of those infected, 66% in the first wave and 62% in the second wave had underlying conditions. The proportion of those exposed to live poultry markets were 80% and 66%, respectively. We recommend permanent closure of live poultry markets and reformation of poultry supply and sales.

Seroprevalence of severe fever with thrombocytopenia syndrome virus in southeastern China and analysis of risk factors.

Severe fever with thrombocytopenia syndrome virus (SFTSV) has been prevalent for some time in China and it was first identified in 2010. However, the seroprevalence of SFTSV in the general population in southeastern China and risk factors associated with the infection are currently unclear. Blood samples were collected from seven counties across Zhejiang province and tested for the presence of SFTSV-specific IgG antibodies by ELISA. A total of 1380 blood samples were collected of which 5·51% were seropositive for SFTSV with seroprevalence varying significantly between sites. Seroprevalence of SFTSV in people who were family members of the patient, lived in the same village as the patient, or lived in a different village than the patient varied significantly. There was significant difference in seroprevalence between participants who bred domestic animals and participants who did not. Domestic animals are probably potential reservoir hosts and contact with domestic animals may be a transmission route of SFTSV.

[Syphilis infection and related factors among HIV-infected patients in Zhejiang Province].

Objective: To investigate syphilis infection and related factors among HIV-infected patients being followed up for more than one year in Zhejiang Province. Methods: Data were collected from the China Disease Control and Prevention Information System, and information such as demographic characteristics, viral load levels, and syphilis serologic test results was collected from HIV-infected persons who were diagnosed with HIV more than 1 year, aged ≥15 years with a current address in Zhejiang Province through December 31, 2022. The logistic regression model analyzed the prevalence of syphilis and the related factors. The SPSS 19.0 software was used for statistical analysis. Results: A total of 33 734 HIV-infected patients, with the prevalence of syphilis was 5.6% (1 879/33 734). Among the syphilis cases, the prevalence of syphilis was 6.4% (1 774/27 934) of males, 7.5% (640/8 543) of 25-34 years old age group, 7.6% (1 025/13 423) of unmarried, 8.3% (1 239/14 862) of homosexual transmission, 6.9% (214/3 080) with a non-local registered residence and 9.6% (602/6 267) with a history of STD before the HIV diagnosis. Multivariate Logistic regression analysis showed that participants who were male (aOR=2.19, 95%CI:1.77-2.72), 25-34 years old age group (aOR=1.80, 95%CI:1.47-2.20), homosexual transmission (aOR=1.67, 95%CI:1.49-1.88), with other provinces registered residence (aOR=1.26, 95%CI:1.09-1.47), and with a history of sexually transmitted disease (STD) before the HIV diagnosis (aOR=1.98, 95%CI:1.78-2.20) were associated with increased risk of syphilis. Being married (aOR=0.79, 95%CI:0.68-0.92) was associated with a decreased risk of syphilis. Conclusions: Syphilis infections were high in HIV-infected patients followed up more than one year in Zhejiang Province. It is recommended that syphilis surveillance and screening frequency should be strengthened among HIV-infected persons with characteristics such as male, homosexual transmission, and STD history.

[Epidemiological characteristics of COVID-19 caused by 2019-nCoV Delta variant in Shangyu district, Shaoxing of Zhejiang province].

Objective: To investigate the epidemiological characteristics of COVID-19 caused by 2019-nCoV Delta variant in Shangyu district, Shaoxing of Zhejiang province in 2021, and provide evidence for the improvement of COVID-19 control and prevention measures. Methods: The incidence data of COVID-19 in Shangyu from December 7 to 21, 2021 was obtained from Shangyu District Center for Disease Control and Prevention. The epidemiological characteristics of the cases, i.e. the population, time and space distributions, were analyzed, and the incubation period and time-varying reproduction numbers (Rt) were calculated. Results: From December 7 to 21, 2021, a total of 380 COVID-19 cases caused by 2019-nCoV Delta variant were detected in Shangyu, the median age of the cases was 52 years, M (Q1，Q3: 38, 61). The male to female ratio of the cases was 1∶1.25, and the cases were mainly workers (36.58%) and farmers (27.63%). The epidemic affected 9 townships (or community) of Shangyu, especially Caoe and Baiguan communities with the cases accounting for 57.10% and 31.53% respectively. The median incubation period of cases was 4.00 days, M (Q1，Q3: 3.00, 5.75). The basic reproduction number (R0) was 4.06, and the Rt was 5.62 in early phase of the outbreak (the highest) and continuously decreased to less than 1.00 within 10 days after the detection of the outbreak. The number of COVID-19 cases decreased to 0 within 14 days after the outbreak (December 7-21), and the main detection methods were screening in centralized isolation (55.53%) and home isolation (40.00%). The infection rates of close contacts and secondary close contacts were 2.06% and 0.46% respectively. Conclusion: The epidemic of COVID-19 in Shangyu characterized by short incubation period, large number of infected people, and case clustering, suggesting the strong transmission of Delta variant (B.1.617.2). Comprehensive prevention and control measures, such as management of close contacts and secondary close contacts, and high-risk area, are essential for the rapid control of the epidemic.

Identification and function of Abdominal-A in the silkworm, Bombyx mori.

Abdominal-A (adb-A) is a key gene in the development of insects. To understand its function in the silkworm, we cloned 1193 bp of the abd-A gene of Bombyx mori (Bmabd-A), including the complete coding sequence and part of the 3' untranslated region sequence. Bmabd-A has at least three mRNA splice variants with coding sequences of lengths 1032, 1044 and 1059 bp, encoding 343, 347 and 352 amino acids, respectively. Each splice variant of Bmabd-A has three exons and differs only in second exon size. Bmabd-A was expressed at low levels in unfertilized eggs, but increased gradually in fertilized eggs after laying 22 h. Bmabd-A expression decreased in ant silkworms (newly hatched silkworms). After RNA interference for Bmabd-A, the embryos had two mutant phenotypes, either completely or partially absent abdominal feet from the third to sixth abdominal segments, suggesting that Bmabd-A is responsible for normal development of the third to sixth abdominal segments during embryonic development.

Continuous positive airway pressure delivery interfaces for obstructive sleep apnoea.

BACKGROUND: Continuous positive airway pressure (CPAP) is the mainstay of therapy for moderate to severe obstructive sleep apnoea (OSA). However, compliance with CPAP has been less than ideal. There are many different CPAP interfaces now available for the treatment of OSA. The type of CPAP delivery interface is likely to influence a patient's acceptance of CPAP therapy and long term compliance. OBJECTIVES: This review aims to compare the efficacy of the various CPAP delivery interfaces available for the treatment of obstructive sleep apnoea. SEARCH STRATEGY: Searches were carried out on the Cochrane Airways Group Specialised Register, CENTRAL, MEDLINE, EMBASE & CINAHL up to January 2006. SELECTION CRITERIA: All randomised, controlled trials comparing different forms of CPAP delivery interface for the treatment of OSA were considered for inclusion. DATA COLLECTION AND ANALYSIS: Two reviewers independently assessed studies for inclusion into the review and extracted data. Attempts were made to contact study authors to obtain additional, unpublished data. MAIN RESULTS: A total of four studies fulfilled the inclusion criteria. Two studies compared nasal mask with the Oracle oral mask and showed no significant difference in compliance at one month (mean difference [95%CI]: 0.17 hours per night [-0.54 to 0.87]). There were also no significant differences in any of the physiological parameters (e.g. AHI, arousal index, minimum oxygen saturation), Epworth Sleepiness Scale (ESS), or symptoms of OSA. A single study comparing nasal mask with nasal pillows showed a significant difference in compliance when expressed as the percentage of days used in favour of nasal pillows (nasal pillows mean+/-SD 94.1+/-8.3%; nasal mask 85.7+/-23.5%, P=0.02), however there were no significant differences in the mean daily use for all days or when use was greater than 0 minutes per day. Nasal pillows were also associated with fewer overall adverse effects (P<0.001) and greater interface satisfaction (P=0.001). No significant differences in AHI, ESS or quality of life scores were seen. One study comparing nasal mask with face mask showed that compliance was significantly greater with use of a nasal mask (mean difference 1.0 hour per night [95%CI 0.3-1.8]). Nasal mask was also associated with significantly lower ESS scores and was the preferred interface in almost all patients. AUTHORS' CONCLUSIONS: Due to the limited number of studies available comparing various interface types, the optimum form of CPAP delivery interface remains unclear. The results of our review suggest that nasal pillows or the Oracle oral mask may be useful alternatives when a patient is unable to tolerate conventional nasal masks. The face mask can not be recommended as a first line interface, but may be considered if nasal obstruction or dryness limits the use of a nasal mask. Further randomised studies comparing the different forms of CPAP delivery interface now available for the treatment of OSA, in larger groups of patients and for longer durations, are required.

Conformational selection of inhibitors and substrates by proteolytic enzymes: implications for drug design and polypeptide processing.

Inhibitors of proteolytic enzymes (proteases) are emerging as prospective treatments for diseases such as AIDS and viral infections, cancers, inflammatory disorders, and Alzheimer's disease. Generic approaches to the design of protease inhibitors are limited by the unpredictability of interactions between, and structural changes to, inhibitor and protease during binding. A computer analysis of superimposed crystal structures for 266 small molecule inhibitors bound to 48 proteases (16 aspartic, 17 serine, 8 cysteine, and 7 metallo) provides the first conclusive proof that inhibitors, including substrate analogues, commonly bind in an extended beta-strand conformation at the active sites of all these proteases. Representative superimposed structures are shown for (a) multiple inhibitors bound to a protease of each class, (b) single inhibitors each bound to multiple proteases, and (c) conformationally constrained inhibitors bound to proteases. Thus inhibitor/substrate conformation, rather than sequence/composition alone, influences protease recognition, and this has profound implications for inhibitor design. This conclusion is supported by NMR, CD, and binding studies for HIV-1 protease inhibitors/substrates which, when preorganized in an extended conformation, have significantly higher protease affinity. Recognition is dependent upon conformational equilibria since helical and turn peptide conformations are not processed by proteases. Conformational selection explains the resistance of folded/structured regions of proteins to proteolytic degradation, the susceptibility of denatured proteins to processing, and the higher affinity of conformationally constrained 'extended' inhibitors/substrates for proteases. Other approaches to extended inhibitor conformations should similarly lead to high-affinity binding to a protease.

Redox sensitive epidithiodioxopiperazines in biological mechanisms of toxicity.

Epidithiodioxopiperazines (ETPs) are a class of secondary metabolites characterized by a bridged disulfide linkage across the alpha,alpha'-positions of the dioxopiperazine ring. This class of compounds displays a range of biological activities, attributed to the sulfur moiety in the oxidized disulfide form and/or the reduced dithiol form. The underlying mechanisms of toxicity of the ETP metabolites are still a matter of debate and this review presents an overview of the evidence for the possible pathways of toxicity.

The stereochemical course of sulphuryl transfer catalysed by arylsulphatase II from Aspergillus oryzae.

Phenyl [(R)-16O,17O,18O]sulphate was synthesized and used to study the stereochemical course of sulphuryl transfer to p-cresol catalysed by arylsulphatase II from Aspergillus oryzae. The reaction was shown to proceed with retention of configuration at the sulphur atom, providing evidence for the involvement of a sulpho-enzyme intermediate on the reaction pathway.

Inactivation of rabbit muscle creatine kinase by reversible formation of an internal disulfide bond induced by the fungal toxin gliotoxin.

The biological activity of gliotoxin is dependent on the presence of a strained disulfide bond that can react with accessible cysteine residues on proteins. Rabbit muscle creatine kinase contains 4 cysteines per 42-kDa subunit and is active in solution as a dimer. Only Cys-282 has been identified as essential for activity. Modification of this residue results in loss of activity of the enzyme. Treatment of creatine kinase with gliotoxin resulted in a time-dependent loss of activity abrogated in the presence of reducing agents. Activity was restored when the inactivated enzyme was treated with reducing agents. Inactivation of creatine kinase by gliotoxin was accompanied by the formation of a 37-kDa form of the enzyme. This oxidized form of creatine kinase was rapidly reconverted to the 42-kDa species by the addition of reducing agents concomitant with restoration of activity. A 1:1 mixture of the oxidized and reduced monomer forms of creatine kinase as shown on polyacrylamide gel electrophoresis was equivalent to the activity of the fully reduced form of the enzyme consistent with only one reduced monomer of the dimer necessary for complete activity. Conversion of the second monomeric species of the dimer to the oxidized form by gliotoxin correlated with loss of activity. Our data are consistent with gliotoxin inducing the formation of an internal disulfide bond in creatine kinase by initially binding and possibly activating a cysteine residue on the protein, followed by reaction with a second neighboring thiol. The recently published crystal structure of creatine kinase suggests the disulfide is formed between Cys-282 and Cys-73.

Euplectin and coneuplectin, new naphthopyrones from the lichen Flavoparmelia euplecta.

Two new naphthopyrones, euplectin (1) and coneuplectin (2), have been isolated from the lichen Flavoparmelia euplecta and their structures elucidated using multidimensional NMR spectroscopic methods, including highfield (600 MHz) gHMBC and gNOE experiments. Cytotoxicity of the more abundant naphthopyrone (1) against the murine P-815 mastocytoma cell line (IC(50) ca. 1.67 microg/mL) has also been evaluated. These compounds are the first lichen metabolites known to contain indenone or indanone moieties in their structure. F. euplecta was also found to contain the known metabolites usnic acid, protocetraric acid, and skyrin.

Evidence for gliotoxin-glutathione conjugate adducts.

The equilibrium constant for the gliotoxin/glutathione pair was found to be 1200+/-100 M(-1) at pH 7.0 at 25 degrees C. Under conditions where the reaction was quenched rapidly with the addition of acid, gliotoxin-glutathione conjugate adducts were detected.