Penning-Trap Mass Measurement of Helium-4

Light-ion trap (LIONTRAP), a high-precision Penning-trap mass spectrometer, was used to determine the atomic mass of ^{4}He. Here, we report a 12 parts-per-trillion measurement of the mass of a ^{4}He^{2+} ion, m(^{4}He^{2+})=4.001 506 179 651(48)  u. From this, the atomic mass of the neutral atom can be determined without loss of precision: m(^{4}He)=4.002 603 254 653(48)  u. This result is slightly more precise than the current CODATA18 literature value but deviates by 6.6 standard deviations.

An Investigation on the Oral Microbiota in Plaque Samples during Orthodontic Treatment

Malocclusion can be corrected by fixed orthodontic appliance therapy. However, ‌the‌ ‌complex‌ ‌appliance design‌‌ ‌and ‌‌the‌ ‌material‌ surface ‌characteristics of the appliance make mechanical debriding difficult, enabling biofilm formation. This‌ ‌study‌ ‌was performed‌ ‌to‌ investigate‌ the‌ ‌microbial‌ ‌load‌ ‌in‌ ‌‌plaque‌ at‌ ‌different‌ time ‌periods‌ ‌of‌ ‌the‌ ‌orthodontic‌ ‌therapy in participants with professionally well-maintained oral hygiene.‌ ‌This‌ ‌prospective‌ ‌study‌ was ‌conducted‌ ‌among‌ ‌12‌ ‌adult‌ ‌‌male‌ ‌participants. Six control (C batch) and six under orthodontic treatment (T batches). Simplified oral hygiene index OHI (S), Plaque index (PlI) and Russell’s Periodontal index (PI) scoring was performed for all subjects prior to sample collection. Plaque‌ ‌samples‌ ‌were‌ ‌collected‌ from both batch T,.and C at similar multiple intervals, corresponding with the sequential archwires for group T in regular use. ‌Six‌ ‌bacterial‌ ‌phyla‌‌ and‌ one‌ ‌fungal‌ ‌phyla ‌examined by subculture.‌ ‌Index scoring revealed that hygiene was maintained throughout study in both the control and treatment batches. A general increase in the microorganisms‌ was noticed,‌ in treatment group ‌reaching‌ ‌a‌ ‌peak‌ ‌at‌ ‌18th ‌month‌ ‌of‌ ‌treatment at T4 and reduced to pretreatment‌ ‌levels on debonding. Though, the microorganisms count increased during treatment, it was not exponential and can be considered favourable flora which matched with the good clinical oral health.

Medical Pedagogy in the Time of COVID-19

Medical teaching is about giving a student a collaborative experience of the art and skill of the practice of medicine. This is acquired through authentic patient experiences. A clinical teacher uses clinical lectures, simulations, lab sessions, small group interactions, cadaver dissection and technical classes (eg: ultrasound) to create a complete clinical immersion experience. For this we use both the in-patient and out-patient facilities.

In-vivo blood flow parameters can predict at-risk aortic aneurysms and dissection: a comprehensive biomechanics model

Background

Abnormal blood flow patterns can alter the material properties of the thoracic aorta via altered vascular biology and tissue biomechanics. In-vivo haemodynamic assessment of the aorta is yet to penetrate clinical practice due to our limited understanding of its effect on aortic wall properties. The decision for surgical treatment is based on size thresholds, limited to a single measurement of aortic diameter from routine imaging, although many aortic dissections (40–60%) occur below these size thresholds. This multi-centre study aims to assess the clinical utility of biomechanics principles in thoracic aortic aneurysm (TAA) risk rupture prediction using a substantial sample size.

Methods

Fifty-five patients undergoing surgery for root or ascending TAA were recruited from five cardiac centres. Bicuspid aortic valves and connective tissue disease were excluded from this study.Haemodynamic assessment Pre-operative 4-dimensional flow magnetic resonance imaging (4D-MRI) were conducted. Direct 4D-flow analysis and computational fluid dynamics (CFD) were performed creating detailed wall shear stress (WSS) maps across the whole aneurysms. Aortic wall assessment The aneurysmal aortic sample was obtained from surgery and subjected to region specific uniaxial failure tests in the circumferential and longitudinal directions, as well as delamination testing within the aortic media. Whole aneurysm histological characterisation was also conducted using computational pathology techniques. Blood flow, tissue mechanics and microstructural properties were used to develop a risk prediction model with assessment of elastin, collagen and smooth muscle cell composition, as well as failure strain assessment and dissection energy function.

Results

Outcomes of mechanical properties were: Young's Elastic Modulus as a measure of aortic stiffness (0.85 MPa ±0.69), as well as maximal tensile strength (0.49 MPa ± 0.36), which demonstrated reduced aortic wall strength in the outer curvature. This correlated with increased wall shear stress (WSS) (up to 10 Pa) and flow velocity (up to 43 l/min). Regions of abnormal flow and tissue mechanics correlated significantly with degraded medial microstructure (elastin abundance: 34 vs 66%; collagen abundance 26 vs 57%, p<0.05).

Conclusions

CFD modelling has the potential to provide a risk prediction of acute events in TAA beyond the current size classification, as validated by altered aortic tissue properties. Future longitudinal studies are warranted to validate this methods in moderately enlarging thoracic aortas.

Flow, mechanical, histology properties

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): NIHR Imperial College BRC

Inhibition of Staphylococcus aureus by crude and fractionated extract from lactic acid bacteria

Increasing levels of antibiotic resistance by Staphyloccocus aureus have posed a need to search for non-antibiotic alternatives. This study aimed to assess the inhibitory effects of crude and fractionated cell-free supernatants (CFS) of locally isolated lactic acid bacteria (LAB) against a clinical strain of S. aureus. A total of 42 LAB strains were isolated and identified from fresh vegetables, fresh fruits and fermented products prior to evaluation of inhibitory activities. CFS of LAB strains exhibiting a stronger inhibitive effect against S. aureus were fractionated into crude protein, polysaccharide and lipid fractions. Crude protein fractions showed greater inhibition against S. aureus compared to polysaccharide and lipid fractions, with a more prevalent effect from Lactobacillus plantarum 8513 and L. plantarum BT8513. Crude protein, polysaccharide and lipid fractions were also characterised with glycine, mannose and oleic acid being detected as the major component of each fraction, respectively. Scanning electron microscopy revealed roughed and wrinkled membrane morphology of S. aureus upon treatment with crude protein fractions of LAB, suggesting an inhibitory effect via the destruction of cellular membrane. This research illustrated the potential application of fractionated extracts from LAB to inhibit S. aureus for use in the food and health industry.

Antimicrobial drug resistance of Staphylococcus aureus in dairy products

OBJECTIVE

To evaluate the prevalence of multidrug resistant Staphylococcus aureus (S. aureus) in dairy products.

METHODS

Isolation and identification of S. aureus were performed in 3 dairy-based food products. The isolates were tested for their susceptibility to 5 different common antimicrobial drugs.

RESULTS

Of 50 samples examined, 5 (10%) were contaminated with S. aureus. Subsequently, the 5 isolates were subjected to antimicrobial resistance pattern using five antibiotic discs (methicillin, vancomycin, kanamycin, chloramphenicol and tetracycline). Sample 29 showed resistance to methicillin and vancomycin. Sample 18 showed intermediate response to tetracycline. The other samples were susceptible to all the antibiotics tested.

CONCLUSIONS

The results provide preliminary data on sources of food contamination which may act as vehicles for the transmission of antimicrobial-resistant Staphylococcus. Therefore, it enables us to develop preventive strategies to avoid the emergence of new strains of resistant S. aureus.

Evaluation of the effect of Cassia surattensis Burm. f., flower methanolic extract on the growth and morphology of Aspergillus niger

BACKGROUND AND AIM

Cassia (C.) surattensis Burm. f. (Leguminosae), a medicinal herb native to tropical equatorial Asia, was commonly used in folk medicine to treat various diseases. The aim of the present study is to investigate the effects of methanolic flower extract of C. surattensis against Aspergillus (A.) niger.

MATERIALS AND METHODS

Antifungal activity of C. surattensis flower extract was studied by using agar disc diffusion method, broth dilution method, percentage of hyphal growth inhibition and scanning electron microscopy (SEM) observation.

RESULTS

The extract exhibited good antifungal activity with zone of inhibition 15 mm and minimum inhibitory concentration (MIC) 6.25 mg/ml. The flower extract exhibited considerable antifungal activity against A. niger with a IC50 of 2.49 mg/ml on the hyphal growth. In scanning electron microscopy (SEM) squashed, collapsed, empty and deformation of hyphae were the major changes observed. Shrunken conidiophores were the obvious alteration on the spores. Morphological alterations observed on A. niger caused by the flower extract could be the contribution of chemical compounds present in the Cassia flower. Phytochemical screening reveals the presence of carbohydrate, tannins, saponins and phenols in the extract. The amount of tannin, total phenolics and flavonoids were estimated to be 55.14 ± 3.11 mg/g, 349.87 ± 5.41 mg/g gallic acid equivalent and 89.64 ± 3.21 mg/g catechin equivalent respectively.

CONCLUSIONS

C. surattensis flower extract potently inhibited the growth of A. niger and are, therefore, excellent candidates for use as the lead compounds for the development of novel antifungal agents.

Anti-Candida activity and brine shrimp toxicity assay of Ganoderma boninense

OBJECTIVES

Ganoderma (G.) boninense is a white rot fungus, which can be found in the palm oil tree. Several studies have shown that G. boninense has antimicrobial and antagonistic properties. However, there is limited information reported on antifungal properties especially on Candida (C) albicans. Hence, this study was conducted to determine the anti-Candida activity of G. boninense against C albicans.

MATERIALS AND METHODS

Crude methanolic extracts of G. boninense was obtained by maceration method with 70% methanol. Anti-Candida test was carried out using disc diffusion assay, broth dilution method, time killing profile and brine shrimp toxicity assay.

RESULTS AND CONCLUSIONS

Anti-Candida activity indicated that the mean zone of inhibition was 12.5 +/- 0.6 mm. The MIC value for C. albicans found to be 3.125 mg/ml. The result from time-killing profile showed that the growth of C albicans was inhibited hence decreases its exponential phase. For brine shrimp toxicity assay, the LC50 value was 3.59 mg/ml which proved that the extract of G. boninense is not toxic.

Optimal protein extraction methods from diverse sample types for protein profiling by using Two-Dimensional Electrophoresis (2DE)

There is a great diversity of protein samples types and origins, therefore the optimal procedure for each sample type must be determined empirically. In order to obtain a reproducible and complete sample presentation which view as many proteins as possible on the desired 2DE gel, it is critical to perform additional sample preparation steps to improve the quality of the final results, yet without selectively losing the proteins. To address this, we developed a general method that is suitable for diverse sample types based on phenolchloroform extraction method (represented by TRI reagent). This method was found to yield good results when used to analyze human breast cancer cell line (MCF-7), Vibrio cholerae, Cryptocaryon irritans cyst and liver abscess fat tissue. These types represent cell line, bacteria, parasite cyst and pus respectively. For each type of samples, several attempts were made to methodically compare protein isolation methods using TRI-reagent Kit, EasyBlue Kit, PRO-PREP™ Protein Extraction Solution and lysis buffer. The most useful protocol allows the extraction and separation of a wide diversity of protein samples that is reproducible among repeated experiments. Our results demonstrated that the modified TRI-reagent Kit had the highest protein yield as well as the greatest number of total proteins spots count for all type of samples. Distinctive differences in spot patterns were also observed in the 2DE gel of different extraction methods used for each type of sample.

In vitro and in situ antiyeast activity of Gracilaria changii methanol extract against Candida albicans

BACKGROUND AND OBJECTIVES

The Gracilaria (G.) sp are widely used in the traditional medicine in Malaysia. The methanol extract of Gracilaria changii B.M. Xia & I.A. Abbott (Gracilariaciae) was evaluated for antiyeast activity against Candida albicans (Berkhout).

MATERIALS AND METHODS

The antiyeast activities were studied by using disc diffusion method and broth dilution method. The effect of the extract on the growth profile of the yeast was also examined via time-kill assay. In addition, the in situ antiyeast activity was studied by microscopic observations using scanning electron microscopy (SEM), transmission electron microscopy (TEM) to determine the major alterations in the microstructure of Candida (C.) albicans.

RESULTS AND DISCUSSION

The extract showed a favourable antimicrobial activity against C albicans with a minimum inhibitory concentration (MIC) value of 1.56 mg/mL. The main abnormalities noted from the SEM and TEM studies were the internal shrinkage of cell, disorganization within the cell cytoplasm and complete collapse of the yeast cells after 36 h of exposure to the extract. The time-kill assay suggested that the G. changii extract significantly inhibited C. albicans growth and it also exhibited prolonged antiyeast activity against the C albicans.

CONCLUSION

The extract has shown in vitro fungicidal properties against C. albicans and should be investigated for its therapeutic potential.

Anti-Candida albicans biofilm activity by Cassia spectabilis standardized methanol extract: an ultrastructural study

BACKGROUND AND OBJECTIVE

Candida (C.) albicans infection in its biofilm mode of growth has taken centre point with the increasing recognition of its role in human infections due to the development of resistance to the commonly used antibiotic or phenotypic adaptation within the biofilm. Hence, in this study the inhibitory effect of methanol extract of Cassia (C.) spectabilis leaves was evaluated against biofilm forming C. albicans.

MATERIALS AND METHODS

Anti-yeast activities were carried out using disc diffusion assay and broth dilution method against biofilm forming C. albicans. C. spectabilis leaves extract was assessed using XTT (2,3-bis [2-Methoxy-4-nitro-5-sulphophenyl]-2H-tetrazolium-5-carboxanilide) reduction assay for biofilm quantification with positive control fluconazole. Scanning electron microscopic (SEM) and confocal scanning laser microscopy (CLSM) analysis further revealed reduction in C. albicans biofilm by C. spectabilis leaves extract.

RESULTS AND DISCUSSION

The methanol extract of C. spectabilis showed a favorable antiyeast activity against C. albicans with MIC (Minimum Inhibitory Concentration) value of 6.25 mg/ml. Fluconazole and leaves extract showed 95.4% and 96.9% biofilm reduction respectively. The main changes observed under scanning electron microscopy after C. spectabilis leaves extract treatment were cellular damage and disruption in biofilms of C. albicans. The ultrastructural changes visualized by SEM were further confirmed using CLSM study.

CONCLUSIONS

The results from this research conclusively exhibit the in vitro anti-biofilm potential of C. spectabilis leaves extract against Candida biofilm.

Effects of Vernonia cinerea less methanol extract on growth and morphogenesis of Candida albicans

BACKGROUND AND OBJECTIVES

Vernonia (V.) cinerea Less (Asteraceae) have many therapeutic uses in the practice of traditional medicine. The methanol extract of V cinerea, was screened for antiyeast activity against pathogenic yeast Candida albicans.

MATERIALS AND METHODS

The antimicrobial activities were studied by using disc diffusion method and broth dilution method. The effect of the extract on the growth profile of the yeast was also examined via time-kill assay. In addition to the fungicidal effects study, microscopic observations using Scanning (SEM) electron microscopy, Transmission (TEM) electron microscopy and light microscopy (LM) were done to determine the major alterations in the microstructure of Candida (C) albicans.

RESULTS AND DISCUSSION

The extract showed a favorable antimicrobial activity against C. albicans with a minimum inhibitory concentration (MIC) value of 1.56 mg/mL. Time-kill assay suggested that Vernonia cinerea extract had completely inhibited Candida albicans growth and also exhibited prolonged antiyeast activity. The main abnormalities notes from these microscopic observations were the alterations in morphology and complete collapse of the yeast cells after 36 h of exposure to the extract.

CONCLUSION

The extract of Vernonia cinerea may be an effective agent to treat the Candida albicans infection.

In vitro and in vivo anticandidal activity of Swietenia mahogani methanolic seed extract

Swietenia mahogani crude methanolic (SMCM) seed extract was investigated for the antifungal activity against Candida albicans which has not been evaluated previously. The antifungal activity was evaluated against C. albicans via disk diffusion, minimum inhibition concentration (MIC), scanning electron microscope (SEM), transmission electron microscope (TEM) and time killing profile. The MIC value of SMCM seed extract is 12.5 mg/ml. The SEM and TEM findings showed there is morphological changes and cytological destruction of C. albicans at the MIC value. Animal model was used to evaluate the in vivo antifungal activity of SMCM seed extract. The colony forming unit (CFU) were calculated per gram of kidney sample and per ml of blood sample respectively for control, curative and ketaconazole treated groups. There was significant reduction for the CFU/ml of blood and CFU/g of kidney. This indicated that the extract was observed to be effective against C. albicans in vitro and in vivo conditions.

Extraction, isolation and characterization of bioactive compounds from plants' extracts

Natural products from medicinal plants, either as pure compounds or as standardized extracts, provide unlimited opportunities for new drug leads because of the unmatched availability of chemical diversity. Due to an increasing demand for chemical diversity in screening programs, seeking therapeutic drugs from natural products, interest particularly in edible plants has grown throughout the world. Botanicals and herbal preparations for medicinal usage contain various types of bioactive compounds. The focus of this paper is on the analytical methodologies, which include the extraction, isolation and characterization of active ingredients in botanicals and herbal preparations. The common problems and key challenges in the extraction, isolation and characterization of active ingredients in botanicals and herbal preparations are discussed. As extraction is the most important step in the analysis of constituents present in botanicals and herbal preparations, the strengths and weaknesses of different extraction techniques are discussed. The analysis of bioactive compounds present in the plant extracts involving the applications of common phytochemical screening assays, chromatographic techniques such as HPLC and, TLC as well as non-chromatographic techniques such as immunoassay and Fourier Transform Infra Red (FTIR) are discussed.

Extraction, isolation and characterization of bioactive compounds from plants' extracts

Natural products from medicinal plants, either as pure compounds or as standardized extracts, provide unlimited opportunities for new drug leads because of the unmatched availability of chemical diversity. Due to an increasing demand for chemical diversity in screening programs, seeking therapeutic drugs from natural products, interest particularly in edible plants has grown throughout the world. Botanicals and herbal preparations for medicinal usage contain various types of bioactive compounds. The focus of this paper is on the analytical methodologies, which include the extraction, isolation and characterization of active ingredients in botanicals and herbal preparations. The common problems and key challenges in the extraction, isolation and characterization of active ingredients in botanicals and herbal preparations are discussed. As extraction is the most important step in the analysis of constituents present in botanicals and herbal preparations, the strengths and weaknesses of different extraction techniques are discussed. The analysis of bioactive compounds present in the plant extracts involving the applications of common phytochemical screening assays, chromatographic techniques such as HPLC and, TLC as well as non-chromatographic techniques such as immunoassay and Fourier Transform Infra Red (FTIR) are discussed.

Effects of Stenochlaena palustris Leaf Extract on Growth and Morphogenesis of Food Borne Pathogen, Aspergillus niger

Some synthetic preservatives have become controversial because they have been proven to cause health problems. These increased health concerns have led consumers to prefer food preservatives based on natural products. Hence, Stenochlaena palustris leaf extract was used in this study to evaluate the antifungal activity against food borne pathogen, Aspergillus niger. The value of minimum inhibitory concentration and minimum fungicidal concentration of leaf extract for this fungus grown on Potato Dextrose Agar medium was 50 mg/ml. IC50 value for the hyphal growth of A. niger was at a concentration of 17.41 mg/ml. Morphology changes of A. niger treated with the fern leaf extract was observed through scanning electron microscope. The thread-like and elongated hyphae cell wall was disrupted, with some appearing flattened and others being broken. Currently, there is growing interest in using natural food preservatives such as medicinal plant extracts for preserving foods to reduce outbreaks of foodborne pathogenic microorganisms. Hence, S. palustris appears to have promise as a safe alternative natural product-based food preservative for future generations.

Extraction, isolation and characterization of bioactive compounds from plants' extracts

Natural products from medicinal plants, either as pure compounds or as standardized extracts, provide unlimited opportunities for new drug leads because of the unmatched availability of chemical diversity. Due to an increasing demand for chemical diversity in screening programs, seeking therapeutic drugs from natural products, interest particularly in edible plants has grown throughout the world. Botanicals and herbal preparations for medicinal usage contain various types of bioactive compounds. The focus of this paper is on the analytical methodologies, which include the extraction, isolation and characterization of active ingredients in botanicals and herbal preparations. The common problems and key challenges in the extraction, isolation and characterization of active ingredients in botanicals and herbal preparations are discussed. As extraction is the most important step in the analysis of constituents present in botanicals and herbal preparations, the strengths and weaknesses of different extraction techniques are discussed. The analysis of bioactive compounds present in the plant extracts involving the applications of common phytochemical screening assays, chromatographic techniques such as HPLC and, TLC as well as non-chromatographic techniques such as immunoassay and Fourier Transform Infra Red (FTIR) are discussed.

Toxicity study of Vernonia cinerea

The methanol extract of Vernonia cinerea Less (Asteraceae), which exhibited antimicrobial activity, was tested for toxicity. In an acute toxicity study using mice, the median lethal dose (LD(50)) of the extract was greater than 2000 mg/kg, and we found no pathological changes in macroscopic examination by necropsy of mice treated with extract. As well as the oral acute toxicity study, the brine shrimp lethality test was also done. Brine shrimp test LC(50) values were 3.87 mg/mL (6 h) and 2.72 mg/mL (24 h), exhibiting no significant toxicity result. In conclusion, the methanol extract of V. cinerea did not produce toxic effects in mice and brine shrimp.

Phytochemical and antimicrobial activity of Swietenia mahagoni crude methanolic seed extract

The present study was designed to evaluate the antibacterial activities of Swietenia mahagoni crude methanolic (SMCM) seed extract. The antimicrobial activity of the oily extract against Gram-positive, Gram-negative, yeast and fungus strains was evaluated based on the inhibition zone using disc diffusion assay, minimal inhibition concentration (MIC) and minimal bactericidal concentration (MBC) values. The crude extract was subjected to various phytochemicals analysis. The demonstrated qualitative phytochemical tests exhibited the presences of common phytocompounds including alkaloids, terpenoids, antraquinones, cardiac glycosides, saponins, and volatile oils as major active constituents. The SMCM seed extract had inhibitory effects on the growth of Candida albicans, Staphylococcus aureus, Pseudomonas aeroginosa, Streptococcus faecalis and Proteus mirabillase and illustrated MIC and MBC values ranging from 25 mg/ml to 50 mg/ml.

Antimicrobial Activity of Emilia sonchifolia DC., Tridax procumbens L. and Vernonia cinerea L. of Asteracea Family: Potential as Food Preservatives

Chemical preservatives have been used in the food industry for many years. However, with increased health concerns, consumers prefer additive-free products or food preservatives based on natural products. This study evaluated antimicrobial activities of extracts from Emilia sonchifolia L. (Common name: lilac tassel flower), Tridax procumbens L. (Common name: tridax daisy) and Vernonia cinerea L. (Common name: Sahadevi), belonging to the Asteracea family, to explore their potential for use against general food spoilage and human pathogens so that new food preservatives may be developed. Three methanol extracts of these plants were tested in vitro against 20 bacterial species, 3 yeast species, and 12 filamentous fungi by the agar diffusion and broth dilution methods. The V. cinerea extract was found to be most effective against all of the tested organisms and the methanol fraction showed the most significant (p < 0.05) antimicrobial activity among all the soluble fractions tested. The minimum inhibitory concentrations (MICs) of extracts determined by the broth dilution method ranged from 1.56 to 100.00mg/mL. The MIC of methanol fraction was the lowest in comparison to the other four extracts. The study findings indicate that bioactive natural products from these plants may be isolated for further testing as leads in the development of new pharmaceuticals in food preservation as well as natural plant-based medicine.

Effects of Clitoria ternatea leaf extract on growth and morphogenesis of Aspergillus niger

Clitoria ternatea is known for its antimicrobial activity but the antifungal effects of leaf extract on growth and morphogenesis of Aspergillus niger have not been observed. The extract showed a favorable antifungal activity against A. niger with a minimum inhibition concentration 0.8 mg/mL and minimum fungicidal concentration 1.6 mg/mL, respectively. The leaf extract exhibited considerable antifungal activity against filamentous fungi in a dose-dependent manner with 0.4 mg/mL IC50 value on hyphal growth of A. niger. The main changes observed under scanning electron microscopy after C. ternatea extract treatment were loss of cytoplasm in fungal hyphae and the hyphal wall and its diameter became markedly thinner, distorted, and resulted in cell wall disruption. In addition, conidiophore alterations were also observed when A. niger was treated with C. ternatea leaf extract.

Prevalence of Helicobacter pylori infection among asymptomatic healthy blood donors in Northern Peninsular Malaysia

Helicobacter pylori infection is recognized as being strongly associated with chronic gastritis, duodenal ulceration and, probably, gastric carcinoma. Seroepidemiological studies have shown that a large proportion of healthy people have antibodies against H. pylori. A serological study was conducted in asymptomatic healthy blood donors in Northern Peninsular Malaysia to assess the seropositivity for H. pylori and to investigate the relationship with ethnic group, gender, ABO blood group and age. A total of 5370 serum samples collected from 3677 male and 1693 female donors in different age groups, and who had no gastrointestinal complaints, were studied with an in-house ELISA for the presence of H. pylori IgG and IgA antibodies. Seven hundred and sixty subjects (14.2%) were seropositive. The overall seropositivity did not differ with ethnicity, gender, ABO blood group and age among asymptomatic healthy blood donors in Northern Peninsular Malaysia.

Antimicrobial activities of Psophocarpus tetragonolobus (L.) DC extracts

Consecutive chloroform, ethanol, and ethyl acetate partitions of extracts from winged bean [Psophocarpus tetragonolobus (L.) DC] root, stem, leaf, and pod extracts were tested for their antimicrobial activity against 19 microbial species, including 11 bacterial pathogens, four yeasts, and four molds using the disk diffusion assay technique. The pod extract was found to be most effective against all of the tested organisms, followed by the stem, root, and leaf extracts, and the ethanol fraction showed the most significant (p < 0.05) antimicrobial activity against all of the tests among three soluble fractions of extract, followed by the ethyl acetate and chloroform fractions. The minimum inhibitory concentrations (MICs) of extracts determined by the broth dilution method ranged from 1.25 to 10.0 mg/mL. The MIC of ethanol fraction of pod extracts was the lowest by comparison with the other two extracts. The MIC for fungi was at or below 2.5 mg/mL and for bacteria was at or above 2.5 mg/mL.

Antimicrobial activities and toxicity of crude extract of the Psophocarpus tetragonolobus pods

The extract of the Psophocarpus tetragonolobus pods has been tested for antimicrobial activity in a disk diffusion assay on eight human pathogenic bacteria and two human pathogenic yeasts. The extracts of P. tetragonolobus possessed antimicrobial activity against all tested strains. The ethanolic extract of P. tetragonolobus pods was further tested for in vivo brine shrimp lethality test and in vitro sheep erythrocyte cytotoxic assay. The brine shrimp lethality test exhibited no significant toxicity (LC(50)=1.88 mg/ml) against Artemia salina, whereas sheep erythrocyte test showed significant toxicity. The reason for haemolysis of erythrocyte was discussed. The P. tetragonolobus extract with high LC(50) value signified that this plant is not toxic to human. This result also suggested that the ethanolic extract of P. tetragonolobus pods is potential source for novel antimicrobial compounds.