New peperomin and polyketides from dichloromethane extract of Peperomia blanda Jack. (Kunth)

Much of the new research and investigation in pharmacy sciences are concerned with developing therapeutic agents, and identifying and finding new drugs with their chemical structure to treat different human diseases such as infectious diseases from natural products. Therefore, the present findings relate to isolating five new compounds the dichloromethane extract of Peperomia blanda (Jacq.) Kunth grown on Socotra Island, Yemen. two new secolignans; which have been proposed as peperomin I & J. These compounds were isolated together with the other two polyketides presented as surinone D and dindygulerione F. The chemical structures were elucidated and confirmed with nuclear magnetic resonance (NMR) and liquid chromatography-mass spectroscopy (LCMS) analysis. These compounds were first isolated and reported from this plant. These new compounds' antimicrobial activity has been evaluated, and minimum inhibitory concentration has been recorded in the range of 125-250 µg/mL. The pharmacotherapeutic spectrum of compounds was predicated using PASS software which showed potential activity.

Thrombocytopenia with absent radii syndrome with delayed presentation of thrombocytopenic episodes: a case report

Bilateral radii aplasia with the presence of both thumbs and episodes of low platelets count are the main characteristics of thrombocytopenia with absent syndrome, which is an unusual birth disorder, with an incidence of 0.42\100 000 population.

Case presentation

The authors reported a case of a 6-month-old baby girl who experienced thrombocytopenia at the age of 6 months for the first time, as a result of cow's milk being introduced for 45 days with chronic diarrhea and growth failure. She had a deviation of the axis of the hand laterally, and a bilateral absent of radii with the presence of both thumbs. In addition, she had abnormal psychomotor development, marasmus case manifestations.

Conclusions

Our aim in publishing the current case report is that clinicians caring for patients with thrombocytopenia with absent syndrome will be aware of the myriad of complications, which may occur in the other organ systems so that they can promptly diagnose and treat any associated abnormalities.

Transforming global health education during the COVID-19 era: perspectives from a transnational collective of global health students and recent graduates

Inspired by the 2021 BMJ Global Health Editorial by Atkinset alon global health (GH) teaching during the COVID-19 pandemic, a group of GH students and recent graduates from around the world convened to discuss our experiences in GH education during multiple global crises. Through weekly meetings over the course of several months, we reflected on the impact the COVID-19 pandemic and broader systemic inequities and injustices in GH education and practice have had on us over the past 2 years. Despite our geographical and disciplinary diversity, our collective experience suggests that while the pandemic provided an opportunity for changing GH education, that opportunity was not seized by most of our institutions. In light of the mounting health crises that loom over our generation, emerging GH professionals have a unique role in critiquing, deconstructing and reconstructing GH education to better address the needs of our time. By using our experiences learning GH during the pandemic as an entry point, and by using this collective as an incubator for dialogue and re-imagination, we offer our insights outlining successes and barriers we have faced with GH and its education and training. Furthermore, we identify autonomous collectives as a potential viable alternative to encourage pluriversality of knowledge and action systems and to move beyond Western universalism that frames most of traditional academia.

Does global health governance walk the talk? Gender representation in World Health Assemblies, 1948-2021

BACKGROUND

While an estimated 70%-75% of the health workforce are women, this is not reflected in the leadership roles of most health organisations-including global decision-making bodies such as the World Health Assembly (WHA).

METHODS

We analysed gender representation in WHA delegations of Member States, Associate Members and Observers (country/territory), using data from 10 944 WHA delegations and 75 815 delegation members over 1948-2021. Delegates' information was extracted from WHO documentation. Likely gender was inferred based on prefixes, pronouns and other gendered language. A gender-to-name algorithm was used as a last resort (4.6%). Time series of 5-year rolling averages of the percentage of women across WHO region, income group and delegate roles are presented. We estimated (%) change ±SE of inferred women delegation members at the WHA per year, and estimated years±SE until gender parity from 2010 to 2019 across regions, income groups, delegate roles and countries. Correlations with these measures were assessed with countries' gender inequality index and two Worldwide Governance indicators.

RESULTS

While upwards trends could be observed in the percentage of women delegates over the past 74 years, men remained over-represented in most WHA delegations. Over 1948-2021, 82.9% of delegations were composed of a majority of men, and no WHA had more than 30% of women Chief Delegates (ranging from 0% to 30%). Wide variation in trends over time could be observed across different geographical regions, income groups and countries. Some countries may take over 100 years to reach gender parity in their WHA delegations, if current estimated trends continue.

CONCLUSION

Despite commitments to gender equality in leadership, women remain gravely under-represented in global health governance. An intersectional approach to representation in global health governance, which prioritises equity in participation beyond gender, can enable transformative policymaking that fosters transparent, accountable and just health systems.

HER3 overexpression and hypomethylation in colorectal adenocarcinoma

INTRODUCTION

Colorectal cancer (CRC) is the third most common cancer worldwide and the second leading cancer in Malaysia. Despite advanced therapies, many cases of recurrence and resistance have been reported. Aberrant DNA methylation of HER3 has been implicated in carcinogenesis of CRC mainly through the regulation of gene expression. Hence, the objective of this study was to determine the status of HER3 DNA methylation and its effects on gene expression in CRC.

MATERIALS AND METHODS

Fifty-nine of archival formalin-fixed, paraffin-embedded CRC cases with the adjacent normal colon tissues were retrieved. Manual micro-dissection was performed prior to RNA and DNA extraction. HER3 gene expression and DNA methylation status was evaluated by qPCR and methylation-specific PCR (MSP) techniques respectively.

RESULTS

Upregulation of HER3 mRNA was found in CRC tissue compared to its adjacent normal colon tissue (8.04-fold). Of 59 CRC samples, 8.5% were methylated and 91.5% were unmethylated (hypomethylation). In the adjacent normal colon tissues, methylated and unmethylated tissue were observed in 6.8%and 93.2% respectively. DNA methylation of HER3 showed a significant association with tumour differentiation and tumour location.

CONCLUSION

This study showed upregulation and hypomethylation of the HER3 gene in CRC cases. Epigenetic alterations were also found in the adjacent normal colon tissues. Thus, upregulation and hypomethylation of HER3 may play a key role in carcinogenesis of CRC. Hypomethylation of CpG islands might be associated with early steps during carcinogenesis. The findings of this biomarker serve a powerful approach to improve the current diagnostic and therapeutic measures.

In vitro haemostatic efficacy of aqueous, methanol and ethanol plant extracts of three medicinal plant species in Palestine

Abstract The haemostatic efficacy of different extract types of Satureja thymbra L., Thymbra spicata L. (Lamiaceae) and Verbascum fruticulosum Post. (Scrophulariaceae) was evaluated in this study via the Prothrombin time (PT) and Activated partial thromboplastin time (aPTT) analysis. Aqueous, methanol and ethanol extracts of the examined plant species leaves were prepared to a final concentration 50 mg/mL. In vitro PT and aPTT assays were conducted on normal platelet poor plasma blood samples by a digital coagulation analyzer. The obtained results revealed anticoagulation activity of all investigated plant species with observed variations among them. The aqueous and ethanol extracts of T. spicata as well as the aqueous extract of S. thymbra prolonged PT values significantly (p < 0.05). While, all V. fruticulosum extract types have had no significant effect on the PT values. The recorded aPTT data showed that all aqueous extracts have had a significant effect on the blood haemostasis as they increased aPTT values in all plant species under study. Out of which, both the ethanol and methanol extracts of T. spicata and methanol extract of S. thymbra showed similar effect. Of great concern, it was clearly noticed that the aqueous and ethanol extract of T. spicata and the aqueous extract of S. thymbra possess the strongest anticoagulation effect as they increased both PT and aPTT values significantly relative to the control (p < 0.05). The variable anticoagulation bioactivity among the studied plant species could be referred to the various solvents degrees of solubility of different phyto-constituents. Thus, the efficacy of the plant species extracts evaluation as anticoagulants or coagulants were related to the plant species and to the solvent of extraction.

Antibacterial test and toxicity of plant seed extracts: a review

Allah has instructed all humankind to eat permissible healthy food according to His guidance as narrated in Al-Quran. Following Maqasid as-Shari’ah, it is a Darruriyyah to ensure the safety of food as an act of protecting life. Therefore, the application of antibacterial agent on food aims to improve the consumers’ health and control the herd immunity. Plant seed is a newly emerged alternative as a source of antibacterial agents. Commonly discarded, the utilisation of plant seed will not only reduce environmental waste issue but also benefited economically to many industries. This article was aimed to review the current literature on antibacterial test and toxicity of various plant seed extracts that potentially contributed to the efficacy of the seed. This review presents a comprehensive analysis of the antibacterial activity assay of the plants' seeds. It covers endpoint and descriptive methods, plant seed toxicity and application of the seed extract in food industries. This review was conducted using the various science-based platform such as Science Direct, Google Scholar, Emerald etc. The keywords ‘antibacterial’, ‘antibacterial seed’, ‘seed extract’ and ‘toxicity seed’ was used in this search.

Discrimination of porcine and bovine gelatines based on reducing sugar types on Maillard reaction

Increasing awareness among Muslims with respect to the Halal status of food has intensified efficient and effective food-source authentications that are science-basedprotocol. Traceability of gelatine to its source remains a daunting scientific task prior to classification of gelatine Halal status. The methodology of this study involves UV-Vis spectroscopic measurement of the degree of browning during Maillard reaction of different gelatine sources with the different type of reducing sugar. D-(+)-xylose has the highest value of browning value (A420nm) of Maillard reaction with gelatine among compared to another type of reducing sugar used. Principle Component Analysis (PCA) used to differentiate the sources of gelatine and successfully identify the major contribution of D-(+)-xylose in the browning value. The score plots of the first principle component (PC1) and the second component (PC2) could be classified and differentiated of gelatine types (porcine, bovine and fish) using variables of browning value of Maillard reaction of gelatinees with different types of sugar, as evaluated using spectrophotometer at 420 nm.

Profiling of how nociceptor neurons detect danger - new and old foes

The host evolves redundant mechanisms to preserve physiological processing and homeostasis. These functions range from sensing internal and external threats, creating a memory of the insult and generating reflexes, which aim to resolve inflammation. Impairment in such functioning leads to chronic inflammatory diseases. By interacting through a common language of ligands and receptors, the immune and sensory nervous systems work in concert to accomplish such protective functions. Whilst this bidirectional communication helps to protect from danger, it can contribute to disease pathophysiology. Thus, the somatosensory nervous system is anatomically positioned within primary and secondary lymphoid tissues and mucosa to modulate immunity directly. Upstream of this interplay, neurons detect danger, which prompts the release of neuropeptides initiating (i) defensive reflexes (ranging from withdrawal response to coughing) and (ii) chemotaxis, adhesion and local infiltration of immune cells. The resulting outcome of such neuro-immune interplay is still ill-defined, but consensual findings start to emerge and support neuropeptides not only as blockers of T_H 1-mediated immunity but also as drivers of T_H 2 immune responses. However, the modalities detected by nociceptors revealed broader than mechanical pressure and temperature sensing and include signals as various as cytokines and pathogens to immunoglobulins and even microRNAs. Along these lines, we aggregated various dorsal root ganglion sensory neuron expression profiling datasets supporting such wide-ranging sensing capabilities to help identifying new danger detection modalities of these cells. Thus, revealing unexpected aspects of nociceptor neuron biology might prompt the identification of novel drivers of immunity, means to resolve inflammation and strategies to safeguard homeostasis.

Dengue protease inhibition activity of selected Malaysian medicinal herbs

Dengue fever is one of major health problem around the world including Malaysia. It is caused by the arthropode-borne flavivirus and transmitted by the bite of the Aedes aegypti or Aedes albopictus mosquito infected with one of the four dengue virus serotypes (DENV-1, DENV-2, DENV-3, or DENV-4). In this study, a screening exercise of various Malaysian medicinal plants showed that the extracts of Lawsonia inermis, Dryobalanops aromatica, Punica granatum, Zizyphus jujuba Lam. and Zingiber zerumbet exhibited potent inhibitory activity against NS2B-NS3 serine protease. The methanol extracts of Dryobalanops aromatica showed inhibition of 99.70 % at concentration of 200 µg/mL with IC₅₀ value of 0.30 ± 0.16 µg/mL.

Phytochemical screening, cytotoxic and antimicrobial activities of Limonium socotranum and Peperomia blanda extracts

Limonium socotranum and Peperomia blanda are used in ethnomedicine to treat several diseases, such as infection, cancer, and inflammation. P. blanda (family: Piperaceae) is from the genus Peperomia, and mostly found in Madagascar, Yemen, USA to South America, while L. socotranum (family: Plumbaginaceae) from the genus Limonium and this species is found only on Socotra Island, Yemen. These plants have attracted great interest in recent years because of their phytochemical contents. Consequently, the current study is aimed to investigate the phytochemical constituents, the cytotoxic and antimicrobial activities of L. socotranum (leaves and stem) and P. blanda extracts. Successive extraction had been performed which resulted in nine crude extracts. Phytochemical screening of the extracts was then conducted using qualitative chemical analysis. The antimicrobial activity of the plant extracts was determined using the well diffusion method against eleven selected pathogenic microbes and the minimum inhibitory concentrations (MIC) were measured. The cytotoxic activities of the plant extracts against MCF-7 and HepG2 cell lines were investigated using sulforhodamine B assay. It was noted that methanol leaves extract from L. socotranum exhibited higher antibacterial activity against Micrococcus luteus (MIC 15.6 µg/mL), Staphylococcus aureus (MIC 125 µg/mL) and Pseudomonas aeruginosa (MIC 125 µg/mL), than stem parts, while petroleum ether extract displayed stronger antifungal activity, with MIC of 125 µg/mL. On the other hand, petroleum ether extract of P. blanda was effective against Gram-positive bacteria and exhibited moderate antifungal activity. Petroleum ether extract of P. blanda displayed cytotoxic activity against MCF-7 cells, with an IC₅₀ of 4.60 ± 0.02 µg/mL, while the methanol extracts showed higher activity against the HepG2 cell line, with an IC₅₀ of 13.90 ± 0.14 µg/mL. Phytochemical findings confirmed the presence of flavonoids, alkaloids and terpenoids. The promising obtained results suggest the potential use of these plants in cancer and antimicrobial therapies.

Development of a bone substitute material based on alpha-tricalcium phosphate scaffold coated with carbonate apatite/poly-epsilon-caprolactone

Interconnected porous tricalcium phosphate ceramics are considered to be potential bone substitutes. However, insufficient mechanical properties when using tricalcium phosphate powders remain a challenge. To mitigate these issues, we have developed a new approach to produce an interconnected alpha-tricalcium phosphate (α-TCP) scaffold and to perform surface modification on the scaffold with a composite layer, which consists of hybrid carbonate apatite / poly-epsilon-caprolactone (CO3Ap/PCL) with enhanced mechanical properties and biological performance. Different CO3Ap combinations were tested to evaluate the optimal mechanical strength and in vitro cell response of the scaffold. The α-TCP scaffold coated with CO3Ap/PCL maintained a fully interconnected structure with a porosity of 80% to 86% and achieved an improved compressive strength mimicking that of cancellous bone. The addition of CO3Ap coupled with the fully interconnected microstructure of the α-TCP scaffolds coated with CO3Ap/PCL increased cell attachment, accelerated proliferation and resulted in greater alkaline phosphatase (ALP) activity. Hence, our bone substitute exhibited promising potential for applications in cancellous bone-type replacement.

Colorectal cancer and its association with the metabolic syndrome: a Malaysian multi-centric case-control study

OBJECTIVE

Colorectal cancer (CRC) and the metabolic syndrome (MetS) are both on the rise in Malaysia. A multi-centric case-control study was conducted from December 2009 to January 2011 to determine any relationship between the two.

METHODS

Patients with confirmed CRC based on colonoscopy findings and cancer free controls from five local hospitals were assessed for MetS according to the International Diabetes Federation (IDF) definition. Each index case was matched for age, gender and ethnicity with two controls (140: 280).

RESULTS

MetS among cases was highly prevalent (70.7%), especially among women (68.7%). MetS as an entity increased CRC risk by almost three fold independently (OR=2.61, 95%CI=1.53-4.47). In men MetS increased the risk of CRC by two fold (OR=2.01, 95%CI, 1.43-4.56), demonstrating an increasing trend in risk with the number of Mets components observed.

CONCLUSION

This study provides evidence for a positive association between the metabolic syndrome and colorectal cancer. A prospective study on the Malaysian population is a high priority to confirm these findings.

Characteristics of persons with spinal cord injury as documented by use of an interactive data system

RATIONALE

Physicians need information about their rehabilitation practices that shows the types of patients being seen and the outcomes for their rehabilitation programs. In order to obtain more information on secondary medical complications and prevention programs, and to provide the information to the spinal cord injury (SCI) rehabilitation team, an interactive data management system was developed.

RESULTS

Initial findings for the first 99 patients with SCI were presented for staff review. Demographic information indicated that patients typically lived in private residences, had at least a high school education, and had annual incomes < $20,000. There were nearly equal numbers of paraplegic and tetraplegic patients; 63% of patients were more than 50 years of age and 69% were more than 10 years post-injury. Over 80% of the patients reported satisfactory health, were physically active, and had adequate transportation. Paraplegic and tetraplegic patients had similar profiles for secondary complications.

CONCLUSIONS

The SCI staff was surprised that greater than 35% of patients with SCI reported current problems with spasticity, pain, and pressure ulcers. The staff was interested in obtaining additional patient-perception information including the severity of each problem, how the problem interfered with daily activity, and the desire for additional care. The staff felt that patients were reporting problems more often to the interviewer than to their physician. There was unanimous support for the ongoing collection of patient-perception information.

Relevance of diffusion through bacterial spore coats/membranes and the associated concentration boundary layers in the initial lag phase of inactivation: A case study for Bacillus subtilis with ozone and monochloramine

Disinfectants are generally used to inactivate microorganisms in solutions. The process of inactivation involves the disinfectant in the liquid diffusing towards the bacteria sites and thereafter reacting with bacteria at rates determined by the respective reaction rates. Such processes have demonstrated an initial lag phase followed by an active depletion phase of bacteria. This paper attempts to study the importance of the combined effects of diffusion of the disinfectant through the outer membrane of the bacteria and transport through the associated concentration boundary layers (CBLs) during the initial lag phase. Mathematical equations are developed correlating the initial concentration of the disinfectant with time required for reaching a critical concentration (C*) at the inner side of the membrane of the cell based on diffusion of disinfectant through the outer membranes of the bacteria and the formation of concentration boundary layers on both sides of the membranes. Experimental data of the lag phases of inactivation already available in the literature for inactivation of Bacillus subtilis spores with ozone and monochloramine are tested with the equations. The results seem to be in good agreement with the theoretical equations indicating the importance of diffusion process across the outer cell membranes and the resulting CBL's during the lag phase of disinfection.

Bioassay-guided isolation of a vasorelaxant active compound from Kaempferia galanga L

Bioassay-guided fractionation was performed on a crude dichloromethane extract of Kaempferia galanga L. using chromatography techniques. Screening of the extract for biological activity started with the brine shrimp lethality bioassay, followed by the study of its antihypertensive activity on anaesthetized rats, which involved monitoring of the extract's effect on mean arterial blood pressure. The components of the fractions obtained from the separation procedures were analyzed using gas chromatography (GC). The yield of the CH(2)Cl(2) extract was 0.29% of the crude plant extract. Analysis of the data for brine shrimp lethality test using the Finney computer program showed that this extract exhibited potent bioactivity with an ED(50) value of 7.92+/-0.13 microgml(-1). Intravenous administration of the extract induced a dose-related reduction of basal mean arterial pressure (MAP) (130+/-5 mmHg) in the anaesthetized rat, with maximal effects seen after 5-10 min of injection. The gas chromatogram showed that the common compound in the active fractions obtained from the bioassay-guided fractionation of the CH(2)Cl(2) extract was ethyl cinnamate. This vasorelaxant active compound, ethyl cinnamate, was isolated as a colorless oil. Ethyl p-methoxycinnamic acid was also isolated as white needles but did not exhibit any relaxant effect on the precontracted thoracic rat aorta.

Induction of a putative metallothionein gene in the blood cockle, Anadara granosa, exposed to cadmium

The relationship between a putative metallothionein gene (MT) and exposure to cadmium (Cd) in blood cockles (Anadara granosa) is reported. In a 96-h dose-response experiment, mortality of cockles was found to proportionately increase in the range of 0.2-5.0 mg/l Cd with a calculated LC(50) of 2.94 mg/l. Exposure to 0.25 mg/l Cd for 16 days caused significant increases (P<0.05) in Cd concentrations in whole tissues, gills and hepatopancreas, and the accumulation of Cd in these tissues increased with the duration of exposure. Two cDNA libraries constructed using the hepatopancreas from control and Cd-treated cockles gave titres of 5.62 x 10(5) and 1.94 x 10(5) pfu/microg vector, respectively. A putative MT gene, AnaMT, of 510 nucleotides in length, was isolated from the treated cDNA library using a heterologous probe MT20 from the blue mussel, Mytilus edulis. Northern analyses using AnaMT as a probe indicated low expression of the MT mRNA in control animals. In cockles treated with 0.25 mg/l Cd for 4 days, MT mRNA level increased to approximately 168%, but declined to 108% at day 8. After 12 and 16 days of Cd treatment, expression of the MT gene was 138% and 187%, respectively, compared to the controls. These observations suggest that induction of the MT gene by a sublethal dose of Cd is rapid, occurring within 4 days of treatment.

Tryptophan-containing mutant of human (group IIa) secreted phospholipase A2 has a dramatically increased ability to hydrolyze phosphatidylcholine vesicles and cell membranes

Human nonpancreatic (group IIa) secreted phospholipase A2 (human sPLA2) is associated with a number of inflammatory disorders in which the extracellular concentrations of this enzyme can become highly elevated. It is probable that the enzyme normally acts as an acute-phase protein whose function is to facilitate the removal of infectious organisms or damaged host cells as part of the normal inflammatory response. The enzyme shows negligible activity with phosphatidylcholine (PC) vesicles and cell membranes, presumably reflecting the enzyme's lack of ability to bind productively to such condensed neutral interfaces. Mammalian pancreatic enzymes show modest activity with such interfaces and contain a unique tryptophan at position 3, which is part of the presumptive interfacial binding surface of these enzymes. Human sPLA2 does not contain tryptophan. The amphiphilic indole side chain of tryptophan is noted for its ability to penetrate the lipid interface of membranes, and tryptophan residues appear to be associated with the ability of lipases and phospholipases A2 to bind to and hydrolyze such interfaces. We have investigated in detail the properties of a V3W mutant of human sPLA2, which has a unique tryptophan on the interfacial binding surface of this enzyme. Although this enzyme shows a modest ( approximately 50%) reduction in activity when anionic substrates are used under standard assay conditions, the activity of the enzyme on phosphatidylcholine vesicles and cell membranes is dramatically increased compared with human sPLA2. This is particularly the case with small unilamellar vesicles of PC, where activity is enhanced over 250-fold compared to the almost zero activity expressed by human sPLA2. This enhanced activity is best explained by increased interfacial binding and activation of the V3W mutant and is not due to enhanced active-site binding and hydrolysis. The results highlight the important role that tryptophan residues can play in interfacial binding, particularly to condensed zwitterionic interfaces. The interfacial characteristics of the mutant human enzyme now resemble more closely the mammalian pancreatic enzymes that already have a tryptophan at position 3.

Phospholipase D and phosphatidic acid enhance the hydrolysis of phospholipids in vesicles and in cell membranes by human secreted phospholipase A2

Phosphatidyl-choline (PC) vesicles and normal cell membranes are resistant to hydrolysis by human group II secreted PLA2, an enzyme that can attain high concentrations in extracellular fluids during many inflammatory processes. This highly cationic enzyme (pI>10.5) has a marked preference for anionic phospholipid interfaces, normally present within the cell. Therefore, the ability of one such anionic phospholipid, phosphatidic acid (PA), to enhance the activity of this enzyme has been investigated in detail. Results using model membrane vesicles and a continuous fluorescence assay highlight the ability of low molar proportions of PA to stimulate vesicle hydrolysis and this stimulation with increasing PA was parallelled by enhanced interfacial binding. In contrast, no productive binding of this enzyme could be detected to the surface of pure PC vesicles. The enhancement of hydrolysis in the presence of PA could also be achieved by prior treatment of pure PC vesicles with PLD, an effect that was dependent on the concentration of PLD and the duration of exposure to this enzyme. The fluorescence assay also allowed cell membranes and whole cells to be used as substrates and whereas such membrane presentations were refractory to hydrolysis by the human enzyme, prior treatment with PLD allowed hydrolysis using concentrations of this PLA2 that would be found extracellularly under inflammatory conditions. These results highlight the potential for PA, generated at the surface of the cell membrane, to be hydrolysed by extracellular human sPLA2 with the generation of lysophosphatidic acid and other lipid mediators and provides one possible mechanism whereby this human sPLA2 could become pro-inflammatory.

Mapping the interfacial binding surface of human secretory group IIa phospholipase A2

Human secretory group IIa phospholipase A2 (hIIa-PLA2) contains a large number of prominent cationic patches on its molecular surface and has exceptionally high affinity for anionic surfaces, including anionic membranes. To identify the cationic amino acid residues that support binding of hIIa-PLA2 to anionic membranes, we have performed extensive site-directed mutagenesis of this protein and measured vesicle binding and interfacial kinetic properties of the mutants using polymerized liposomes and nonpolymerized anionic vesicles. Unlike other secretory PLA2s, which have a few cationic residues that support binding of enzyme to anionic membranes, interfacial binding of hIIa-PLA2 is driven in part by electrostatic interactions involving a number of cationic residues forming patches on the putative interfacial binding surface. Among these residues, the amino-terminal patch composed of Arg-7, Lys-10, and Lys-16 makes the most significant contribution to interfacial adsorption, and this is supplemented by contributions from other patches, most notably Lys-74/Lys-87/Arg-92 and Lys-124/Arg-127. For these mutants, complete vesicle binding occurs in the presence of high vesicle concentrations, and under these conditions the mutants display specific activities comparable to that of wild-type enzyme. These studies indicate that electrostatic interactions between surface lysine and arginine residues and the interface contribute to interfacial binding of hIIa-PLA2 to anionic vesicles and that cationic residues closest to the opening of the active-site slot make the most important interactions with the membrane. However, because the wild type binds extremely tightly to anionic vesicles, it was not possible to exactly determine what fraction of the total interfacial binding energy is due to electrostatics.

Human non-pancreatic (group II) secreted phospholipase A2 expressed from a synthetic gene in Escherichia coli: characterisation of N-terminal mutants

A gene coding for human non-pancreatic (group II) secreted phospholipase A2 (hnpsPLA2) has been constructed by the single-step ligation of twelve synthetic oligonucleotides. The gene has been cloned into a modification of the bacterial expression vector pET 11 which allows protein over-expression as inclusion bodies and enables about 3 mg/litre of pure refolded fully active enzyme to be obtained. The protein was expressed as a 1-Ala mutant (N1A) to allow removal of the initiator methionine by the Escherichia coli amino-peptidase. This mutant had very similar properties to the wild-type enzyme. A double mutant, N1A, V3W was also constructed and expressed in high yield. This tryptophan-containing mutant showed similar properties to the wild-type and N1A mutant but had about 40% of the activity under the assay conditions used. This tryptophan was used as a reporter group for interfacial binding and its properties were compared to those of the corresponding tryptophan in PLA2 from procine pancreas. Expression of the wild-type gene sequence for hnpsPLA2 in E. coli gave the expected mutant protein still with the initiator methionine and with much reduced activity. Interfacial binding of all hnpsPLA2 mutants to anionic phospholipids was very similar when assessed by fluorescence methods. Comparisons of these mutants with the pancreatic enzyme revealed significant differences in terms of the effect of calcium on interfacial binding. The ability to express reasonably large amounts of the N1A mutant in E. coli will provide a basis for future site directed mutagenesis studies of this important human enzyme.

Human non-pancreatic (group II) secreted phospholipase A2 expressed from a synthetic gene in Escherichia coli: characterisation of N-terminal mutants

A gene coding for human non-pancreatic (group II) secreted phospholipase A2 (hnpsPLA2) has been constructed by the single-step ligation of twelve synthetic oligonucleotides. The gene has been cloned into a modification of the bacterial expression vector pET 11 which allows protein over-expression as inclusion bodies and enables about 3 mg/litre of pure refolded fully active enzyme to be obtained. The protein was expressed as a 1-Ala mutant (N1A) to allow removal of the initiator methionine by the Escherichia coli amino-peptidase. This mutant had very similar properties to the wild-type enzyme. A double mutant, N1A, V3W was also constructed and expressed in high yield. This tryptophan-containing mutant showed similar properties to the wild-type and N1A mutant but had about 40% of the activity under the assay conditions used. This tryptophan was used as a reporter group for interfacial binding and its properties were compared to those of the corresponding tryptophan in PLA2 from procine pancreas. Expression of the wild-type gene sequence for hnpsPLA2 in E. coli gave the expected mutant protein still with the initiator methionine and with much reduced activity. Interfacial binding of all hnpsPLA2 mutants to anionic phospholipids was very similar when assessed by fluorescence methods. Comparisons of these mutants with the pancreatic enzyme revealed significant differences in terms of the effect of calcium on interfacial binding. The ability to express reasonably large amounts of the N1A mutant in E. coli will provide a basis for future site directed mutagenesis studies of this important human enzyme.

Interactive database management (IDM)

Interactive database management (IDM) is a data editing software that provides complete data editing at the time of initial data entry when information is 'fresh at hand'. Under the new interactive system, initial data recording is subjected to instant data editing by the interactive computer software logic. Data are immediately entered in final form to the database and are available for analysis. IDM continuously checks all variables for acceptability, completeness, and consistency. IDM does not allow form duplication. Many functions including backups have been automated. The interactive system can export the database to other systems. The software has been implemented for two Department of Veterans Affairs Cooperative Studies (CCSHS #5 and CSP #385) which collect data for 1400 and 1000 variables, respectively at 28 VA medical centers. IDM is extremely user friendly and simple to operate. Researchers with no computer background can be trained quickly and easily to use the system. IDM is deployed on notebook microcomputers making it portable for use anywhere in the hospital setting.