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Health-care professionals exposed to latex allergy: a cause of concern?

Das S

ANZ J Surg, 2008 Nov;78(11):939.
PMID: 18959687 DOI: 10.1111/j.1445-2197.2008.04708.x
Matched MeSH terms: Latex/adverse effects*; Latex Hypersensitivity/epidemiology*
Tensile properties of vulcanized field natural rubber latex by electron beam

Chai CK, Md. Soot Ahmad, Wan Manshol W. Zin

Sains Malaysiana, 2008;37.

Electron beam vulcanization of natural rubber latex has been developed as an alternative to the conventional sulphur vulcanization method. This study aimed at determining the effect of electron beam dose, beam current and centrifugation to the tensile properties of field natural rubber latex. Irradiation dose and beam current ranged from 50 to 300 kGy and 1 to 15 mA respectively. The determination of tensile properties were done on cast film prepared from irradiated field latex before and after centrifugation. It was found that tensile properties increased with radiation dose but decreased with beam current. Rubber films made from centrifuged irradiated field latex were softer and showed higher tensile strength.

Matched MeSH terms: Latex
Legionella species and serogroups in Malaysian water cooling towers: identification by latex agglutination and PCR-DNA sequencing of isolates

Yong SF, Goh FN, Ngeow YF

J Water Health, 2010 Mar;8(1):92-100.
PMID: 20009251 DOI: 10.2166/wh.2009.002

In this study, we investigated the distribution of Legionella species in water cooling towers located in different parts of Malaysia to obtain information that may inform public health policies for the prevention of legionellosis. A total of 20 water samples were collected from 11 cooling towers located in three different states in east, west and south Malaysia. The samples were concentrated by filtration and treated with an acid buffer before plating on to BCYE agar. Legionella viable counts in these samples ranged from 100 to 2,000 CFU ml(-1); 28 isolates from the 24 samples were examined by latex agglutination as well as 16S rRNA and rpoB PCR-DNA sequencing. These isolates were identified as Legionella pneumophila serogroup 1 (35.7%), L. pneumophila serogroup 2-14 (39%), L. pneumophila non-groupable (10.7%), L. busanensis, L. gormanii, L. anisa and L. gresilensis. L. pneumophila was clearly the predominant species at all sampling sites. Repeat sampling from the same cooling tower and testing different colonies from the same water sample showed concurrent colonization by different serogroups and different species of Legionella in some of the cooling towers.

Matched MeSH terms: Latex Fixation Tests
Fulltext Development of biodegradable plastic composite blends based on sago derived starch and natural rubber

Kiing, Sie Cheong, Balasubramaniam, Jaya-Raj, Yiu, Pang Hung, Wong, Sie Chuong, Amartalingam, Rajan

Pertanika Journal of Science & Technology, 2010;18(2):-.
MyJurnal

Polyethylene is a widely used packaging material, but its non-biodegradable nature can lead to waste
disposal problems. This increases the concern in research and development of biodegradable plastics from natural resource as alternatives to petroleum-derived plastics. In this study, biodegradable plastic composites were prepared by blending thermoplastic starch with natural rubber in the present of glycerol as plasticizer. Local sago starch was cast with 0.5 to 10% of natural rubber to prepare the bioplastic. The products were characterized by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), water absorption test, biodegradable test, hydrolysis test, and mechanical analysis. Meanwhile, composite with natural rubber latex was increased from 0.5 to 10% showing that the melting temperature is in the range of 120 to 150˚C, but with no significant difference. The water absorption characteristics, biodegradability, and tensile strength decreased by 11.21%, 30.18%, and 20.733 MPa, respectively. However, the elongation at break was increased from 26.67 to 503.3%. The findings of this study showed that sago starch has a great potential in bioplastic production with good miscibility and compatibility.

Matched MeSH terms: Latex
Fulltext Vulcanisation and coagulant dipping of epoxidised natural rubber latex

Dazylah Darji, Ma'zam Md Said

Pertanika Journal of Science & Technology, 2010;18(2):-.
MyJurnal

Epoxidised Natural Rubber (ENR) is now a commercially available polymer produced by chemical modification of natural rubber. Currently, three types of ENR are commercially available, and these are ENR 10, ENR 25, and ENR 50 with 10%, 25%, and 50% mol epoxidation, respectively. Studies on prevulcanisation of ENR 50 and postvulcanisation of the latex films were carried out. The objective of this study was to develop ENR 50 that could be dipped easily in coagulant dipping solution to produce dipped products. Several attempts were made by compounding prevulcanised ENR 50 at various sulphur levels ranging from 0.5 to 3.0 pphr. Using suitable coagulant dipping systems, ENR 50 film could be formed despite the high contents of non-ionic surfactant. It was found that the tensile strength of prevulcanised ENR 50 film decreased with the increase in the sulphur level. The results show that as level of sulphur increased, M300 also increased to an optimum value of 1.5 pphr of sulphur. For the postvulcanised ENR 50 film, however, the tensile strength increased and then decreased with the increasing sulphur level. Meanwhile M300 increased with the increasing postvulcanization time and sulphur level. The postvulcanisation of ENR 50 film seems to be a more effective way of increasing tensile properties than by prevulcanisation of ENR 50.

Matched MeSH terms: Latex
Fulltext Microwave dielectric characterization of hevea rubber latex at 2.6, 10 and 18 GHz

Kaida Khalid, W. Mohd. Daud W. Yusoff, Jumiah Hassan

Pertanika Journal of Science & Technology, 2010;18(1):-.
MyJurnal

Dielectric properties of natural rubber Hevea brasiliensis latex were measured at frequencies 0.2 to 20 GHz, at temperatures of 2, 15, 25, 35, and 50oC and around 30-98% moisture content. Measurements were done using open-ended coaxial line sensor and automated network analyzer. As expected, results showed that dielectric constant increased with increasing moisture. From 0.2 to 2.6 GHz, the losses were governed by conductive losses but for frequencies greater than 2.6 GHz, these were mainly due to dipolar losses. The former is due to conducting phases in hevea latex, while the latter is mainly governed by the orientation of water molecules. The results were analyzed at 2.6, 10, and 18 GHz, respectively. These were then compared with the values predicted by the dielectric mixture equations recommended by Weiner, Bruggeman and Kraszewski. All the measured values were found to be within the Weiner’s boundaries and close to the upper limit of Weiner’s model. It is also close to the predicted values of Bruggeman’s model with a/b = 0.1. All the models including Kraszewski are suitable for predicting the dielectric properties of hevea latex for frequencies 2.6 to 18 GHz, moisture content 30 to 98% and temperatures 2 to 50oC.

Matched MeSH terms: Latex
Anti-fungal effect of Hevea brasiliensis latex C-serum on Aspergillus niger

Daruliza KM, Lam KL, Yang KL, Priscilla JT, Sunderasan E, Ong MT

Eur Rev Med Pharmacol Sci, 2011 Sep;15(9):1027-33.
PMID: 22013725

Hevea brasiliensis extract could potentially be employed as a relatively low cost resource for various anti-fungal activities due to the simplicity of latex preparation and the abundance of latex that can be obtained in rubber producing regions. The present study was aimed at examining the species specific anti-fungal property of H. brasilensis latex C-serum against Aspergillus niger.

Matched MeSH terms: Latex/isolation & purification; Latex/pharmacology*; Latex/toxicity
Anti-Candida albicans activity and brine shrimp lethality test of Hevea brasiliensis latex B-serum

Daruliza KM, Yang KL, Lam KL, Priscilla JT, Sunderasan E, Ong MT

Eur Rev Med Pharmacol Sci, 2011 Oct;15(10):1163-71.
PMID: 22165677

Hevea brasiliensis extracts could potentially be employed as a relatively low cost resource for various anti-fungal activities due to the simplicity of the extract preparation and its abundance especially in the tropical region. Latex B-serum was reported to have anti-cancer property and its specificity in anti-fungal property has not been elucidated. The present study was conducted to determine the anti-fungal activity of Hevea latex B-serum against Candida (C.) albicans (a rounded cell fungus) and Aspergillus (A.) niger (a filamentous fungus).

Matched MeSH terms: Latex/pharmacology*; Latex/toxicity
Fulltext Microcellular rubber: a study on reclaimed natural rubber (NR) latex gloves/Standard Malaysian Rubber (SMR) 20 blends

Wan, Ngeow Yen, Chin, Khaw Pei, Che Su Mt. Saad

Pertanika Journal of Science & Technology, 2011;19(1):171-176.
MyJurnal

Reclaimed rubber from rejected natural rubber (NR) latex gloves (r-NRG) was evaluated as partial
replacement for Standard Malaysian Rubber (SMR) 20 in producing microcellular rubber. In the study, the amount of reclaimed rubber varied from 20 pphr to 95 pphr for the purpose of cost reduction, environmental interest and as processing aids in reducing internal porosity, swells and to minimize shrinkage and air-trapped problems in producing microcellular rubber. A typical formulation in making microcellular rubber slab was developed and two-roll mill was used for compounding. The cure characteristics and mechanical properties, such as density, hardness, tensile strength, and elongation at break, were evaluated. Scorch time and cure rate index performed marginal decreased with increasing of r-NRG content. 95 pphr r-NRG blends showed a consequential drop in hardness. Both tensile properties and elongation at break decreased as the r-NRG content was increased.

Matched MeSH terms: Latex
Fulltext Investigation of stx 2 + eae + Escherichia coli O157:H7 in beef imported from Malaysia to Thailand

International Food Research Journal, 2011;18(1):381-386.
MyJurnal

To gain insight into the microbiological safety of food products routinely traded across international borders in Southeast Asian countries, beef imported from Malaysia to southern Thailand was examined for contamination with Escherichia coli O157 and its subsequent spread into the imported areas. We screened 31 samples exported from Malaysia and 36 domestic Thai samples. Isolation methods including an O157 antigen-targeted immunomagnetic separation technique, screening on CHROMagar O157 medium, and serotype confirmation of E. coli isolates by specific agglutination tests were employed. Fourteen strains of E. coli O157:H7 were isolated from eight Malaysian samples (25.8%) and six strains from four Thai samples (11.1%). These strains were of the stx1-stx2+eae+ genotype except one Malaysian strain which was of the stx1- stx2- eae+ genotype. All 19 O157:H7 strains possessing the stx2 gene produced little or no Stx2 (reversed passive latex agglutination titer ≤ 4). Of the 19 strains, five Malaysian (38.5%) and two Thai (33.3%) strains exhibited resistance to a set of antibiotics. Finally, the results of two DNA fingerprinting
analyses (O157 IS-printing targeted to IS629 and pulsed-field gel electrophoresis, PFGE) of the O157:H7 strains possessing the stx2 gene, indicated that the Malaysian and Thai strains are closely related. Therefore, E. coli O157:H7 might be transferred from Malaysia to southern Thailand through beef trade.

Matched MeSH terms: Latex; Latex Fixation Tests
Fulltext Metabolic routes affecting rubber biosynthesis in Hevea brasiliensis latex

Chow KS, Mat-Isa MN, Bahari A, Ghazali AK, Alias H, Mohd-Zainuddin Z, et al.

J Exp Bot, 2012 Mar;63(5):1863-71.
PMID: 22162870 DOI: 10.1093/jxb/err363

The cytosolic mevalonate (MVA) pathway in Hevea brasiliensis latex is the conventionally accepted pathway which provides isopentenyl diphosphate (IPP) for cis-polyisoprene (rubber) biosynthesis. However, the plastidic 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway may be an alternative source of IPP since its more recent discovery in plants. Quantitative RT-PCR (qRT-PCR) expression profiles of genes from both pathways in latex showed that subcellular compartmentalization of IPP for cis-polyisoprene synthesis is related to the degree of plastidic carotenoid synthesis. From this, the occurrence of two schemes of IPP partitioning and utilization within one species is proposed whereby the supply of IPP for cis-polyisoprene from the MEP pathway is related to carotenoid production in latex. Subsequently, a set of latex unique gene transcripts was sequenced and assembled and they were then mapped to IPP-requiring pathways. Up to eight such pathways, including cis-polyisoprene biosynthesis, were identified. Our findings on pre- and post-IPP metabolic routes form an important aspect of a pathway knowledge-driven approach to enhancing cis-polyisoprene biosynthesis in transgenic rubber trees.

Matched MeSH terms: Latex/analysis*
Anti-proliferation effect of Hevea brasiliensis latex B-serum on human breast epithelial cells

Lee YK, Lay LK, Mahsufi MS, Guan TS, Elumalai S, Thong OM

Pak J Pharm Sci, 2012 Jul;25(3):645-50.
PMID: 22713955

The rubber tree (Hevea brasiliensis) extracts are becoming increasingly visible in pharmaceutical and therapeutical research. The present study is aimed at examining the specific anti-proliferation property of H. brasiliensis latex B-serum sub-fractions against human breast cancer epithelial cell lines MCF-7 and MDA-MB231. The results showed that the latex whole B-serum and DBP sub-fraction exerted a specific anti-proliferation activity against cancer-origin cells MDA-MB231 but had little effect on non-cancer-origin cells. On the other hand, the anti-proliferative activity was diminished in the pre-heated B-serum fractions. With the low toxicity that the B-serum demonstrated previously in Brine Shrimp Lethality Test (BSLT), the present results suggest the potential use of the B-serum sub-fractions in cancer treatment.

Matched MeSH terms: Latex/pharmacology*; Latex/toxicity
Fulltext Latex C-serum from Hevea brasiliensis induces non-apoptotic cell death in hepatocellular carcinoma cell line (HepG2)

Lam KL, Yang KL, Sunderasan E, Ong MT

Cell Prolif, 2012 Dec;45(6):577-85.
PMID: 23046445 DOI: 10.1111/j.1365-2184.2012.00841.x

OBJECTIVES: Latex from Hevea brasiliensis (natural rubber tree primarily cultivated for its rubber particles) has no known primary metabolic function, although its biological role is as a plant defence system. The present study has evaluated specific anti-proliferative effects of latex whole C-serum and its subfractions, on human cancer cell lines.
MATERIALS AND METHODS: Cell viability assay using MTT, DNA fragmentation assay and real-time PCR were used to evaluate the cytotoxic effects of latex whole C-serum and its subfractions on the cell lines.
RESULTS: MTT assay revealed very low LC(50) values, 2.0 and 280 ng/ml, for DCS and DCP treatments, respectively. DCS was proven to be more potent compared to DCP, in conferring specific anti-proliferative effects on the cancer cell lines. The study also indicated that anti-proliferative activity of pre-heated C-serum fractions diminished significantly.
CONCLUSION: Although noteworthy cell death was reported, DNA fragmentation assay and real-time PCR confirmed that that induced by latex C-serum subfractions was not promoted via the classical apoptotic signalling pathway.

Matched MeSH terms: Latex/isolation & purification; Latex/pharmacology*; Latex/chemistry
Fulltext Sludge-derived fuel from latex products manufacturing industry

Devaraj, V., Zairossani, M.N.

ASM Science Journal, 2012;6(1):15-21.
MyJurnal

Malaysia is the world’s top manufacturer of examination and surgical natural rubber (NR) gloves, exported mainly to the USA and Europe. The glove manufacturing process yields effluent which must be treated to comply with the stringent regulatory requirements imposed by the Malaysian Department of Environment. To make glove manufacturing an eco-friendly process, efforts are geared towards minimizing and utilizing waste or converting it into raw material for making value-added products. Waste generated from the glove industry is mainly rubber sludge which is obtained from the chemical flocculation stage of the effluent treatment process and consists of mainly rubber, remnants of compounding ingredients and water. R&D work by the Malaysian Rubber Board on waste utilization and resource recovery investigations have revealed many uses for this sludge. This paper briefly outlines only one of the many options available, which is the conversion of the sludge into sludge derived fuel (SDF). Preliminary study has identified three formulations of SDF with calorific values (CV) exceeding 16 000 kJ/kg, matching a good grade coal. This was considered as promising results which warrant explorative work for further increasing the CV of SDF to turn it into a viable fuel substitute in the latex products manufacturing industry and subsequently apply for a Clean Development Mechanism status to generate income.

Matched MeSH terms: Latex
Fulltext Detection of pipeline intelligent gauge jammed in pipeline by neutron device

Md Fakarudin Ab Rahman, Ismail Mustapha, Nor Pa’iza Mohd Hasan, Ibrahim, Pairu

Jurnal Sains Nuklear Malaysia, 2012;24(2):35-41.
MyJurnal

In industrial plants such as electricity generating, petroleum, chemical and petrochemical plants, pipelines are used extensively to transport liquid from one location to another. In radiation vulcanization of natural rubber latex (RVNRL) plants, pipelines are also used to transport latex to storage tank. During one of its maintenance activities, a pipeline intelligent gauge (PIG) that was used to monitor pipe integrity jammed inside the pipe causing interruption to its operation or loading activities. Sealed source technology was utilized to determine the location of jammed PIG in the pipeline. Fast neutrons from a 50 mCi Americium Beryllium (AmBe241), with energy range between 0.5 to11 MeV, were used for the study. Helium 3 (He3) detector was used to detect slow neutrons having a range of energy of 30 eV- 0.5 MeV. The investigation was carried out using neutron backscatter technique scanner. By adopting back-scattered technique, the location of jammed PIG in the pipeline has been successfully determined.

Matched MeSH terms: Latex
Fulltext Evaluation of PCR-based approach for serotype determination of Streptococcus pneumoniae

Shakrin NN, Balasubramaniam SD, Yusof HA, Mastuki MF, Masri SN, Taib NM, et al.

Trop Biomed, 2013 Jun;30(2):338-44.
PMID: 23959499 MyJurnal

Determination of Streptococcus pneumoniae serotypes is essential for epidemiological surveillance. Therefore accurate, reliable and cost effective serotyping method is crucial. In this study, we determined the serotypes of 41 pneumococcal isolates recovered from human anterior nares by multiplex Polymerase Chain Reaction (PCR) utilizing published primers. The data was then compared with conventional serology using latex agglutination (LA) and the Quellung reaction. Based on the PCR-approach, 8 different serogroups/serotypes were detected with one isolate classified as non-typeable (cpsA-negative). In reference to the serology-based data, the results were in agreement except for one isolate. For the latter isolate, the LA and Quellung tests failed to show a reaction but the PCR-approach and sequencing identified the isolate as serogroup 15B/C. Based on this experimental setting, we found that the PCR-approach for pneumococcal serotypes determination is reliable to serve as the alternative for determining the pneumococcal serotyping.

Matched MeSH terms: Latex Fixation Tests
Effect of one-step polishing system on the color stability of nanocomposites

Alawjali SS, Lui JL

J Dent, 2013 Aug;41 Suppl 3:e53-61.
PMID: 23103847 DOI: 10.1016/j.jdent.2012.10.008

This study was to compare the effect of three different one-step polishing systems on the color stability of three different types of nanocomposites after immersion in coffee for one day and seven days and determine which nanocomposite material has the best color stability following polishing with each of the one-step polishing system.

Matched MeSH terms: Latex/chemistry
Fulltext Draft genome sequence of the rubber tree Hevea brasiliensis

Rahman AY, Usharraj AO, Misra BB, Thottathil GP, Jayasekaran K, Feng Y, et al.

BMC Genomics, 2013;14:75.
PMID: 23375136 DOI: 10.1186/1471-2164-14-75

Hevea brasiliensis, a member of the Euphorbiaceae family, is the major commercial source of natural rubber (NR). NR is a latex polymer with high elasticity, flexibility, and resilience that has played a critical role in the world economy since 1876.

Matched MeSH terms: Latex/metabolism
Preparation and characterization of potato starch nanocrystal reinforced natural rubber nanocomposites

Rajisha KR, Maria HJ, Pothan LA, Ahmad Z, Thomas S

Int J Biol Macromol, 2014 Jun;67:147-53.
PMID: 24657376 DOI: 10.1016/j.ijbiomac.2014.03.013

Potato starch nanocrystals were found to serve as an effective reinforcing agent for natural rubber (NR). Starch nanocrystals were obtained by the sulfuric acid hydrolysis of potato starch granules. After mixing the latex and the starch nanocrystals, the resulting aqueous suspension was cast into film by solvent evaporation method. The composite samples were successfully prepared by varying filler loadings, using a colloidal suspension of starch nanocrystals and NR latex. The morphology of the nanocomposite prepared was analyzed by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). FESEM analysis revealed the size and shape of the crystal and their homogeneous dispersion in the composites. The crystallinity of the nanocomposites was studied using XRD analysis which indicated an overall increase in crystallinity with filler content. The mechanical properties of the nanocomposites such as stress-strain behavior, tensile strength, tensile modulus and elongation at break were measured according to ASTM standards. The tensile strength and modulus of the composites were found to improve tremendously with increasing nanocrystal content. This dramatic increase observed can be attributed to the formation of starch nanocrystal network. This network immobilizes the polymer chains leading to an increase in the modulus and other mechanical properties.

Matched MeSH terms: Latex/chemistry
First Report of Rubber Tree Stem Rot Caused by Fusarium oxysporum in China

Li BX, Shi T, Liu XB, Lin CH, Huang GX

Plant Dis, 2014 Jul;98(7):1008.
PMID: 30708897 DOI: 10.1094/PDIS-01-14-0004-PDN

Rubber tree (Hevea brasiliensis) is an important crop in tropical regions of China. In October 2013, a new stem rot disease was found on cv. Yunyan77-4 at a rubber tree plantation in Hekou, Yunnan Province. There were about 100 plants, and diseased rubber trees accounted for 30% or less. Initially, brown-punctuate secretion appeared on the stem, which was 5 to 6 cm above the ground. Eventually, the secretion became black and no latex produced from the rubber tree bark. After removing the secretion, the diseased bark was brown putrescence, but the circumambient bark was normal. Upon peeling the surface bark, the inner bark and xylem had brown rot and was musty. The junction between health and disease was undulate. On the two most serious plants, parts of leaves on the crown were yellow, and the root near the diseased stem was dry and puce. The pathogen was isolated and designated HbFO01; the pathogenicity was established by following Koch's postulates. The pathogen was cultivated on a potato dextrose agar (PDA) plate at 28°C for 4 days. Ten plants of rubber tree cv. Yunyan77-4 were selected from a disease-free plantation in Haikou, Hainan Province, and the stem diameter was about 7 cm. The bark of five plants was peeled, and one mycelium disk with a diameter of 1 cm was inserted into the cut and covered again with the bark. The other five plants were treated with agar disks as controls. The inoculation site was kept moist for 2 days, and then the mycelium and agar disk were removed. On eighth day, symptoms similar to the original stem lesions were observed on stems of inoculated plants, while only scars formed on stems of control plants. The pathogen was re-isolated from the lesions of inoculated plants. On PDA plates, the pathogen colony was circular and white with tidy edges and rich aerial hyphae. Microscopic examination showed microconidia and chlamydospores were produced abundantly on PDA medium. The falciform macroconidia were only produced on lesions and were slightly curved, with a curved apical cell and foot shaped to pointed basal cell, usually 3-septate, 16.2 to 24.2 × 3.2 to 4.0 μm. Microconidia were produced in false heads, oval, 0-septate, 6.2 to 8.2 × 3.3 to 3.8 μm, and the phialide was cylindrical. Chlamydospores were oval, 6.4 to 7.2 × 3.1 to 3.8 μm, alone produced in hypha. Morphological characteristics of the specimen were similar to the descriptions for Fusarium oxysporum (2). Genomic DNA of this isolate was extracted with a CTAB protocol (4) from mycelium and used as a template for amplification of the internal transcribed spacer (ITS) region of rDNA with primer pair ITS1/ITS4 (1). The full length of this sequence is 503 nt (GenBank Accession No. KJ009335), which exactly matched several sequences (e.g., JF807394.1, JX897002.1, and HQ451888.1) of F. oxysporum. Williams and Liu had listed F. oxysporum as the economically important pathogen of Hevea in Asia (3), while this is, to our knowledge, the first report of stem rot caused by F. oxysporum on rubber tree in China. References: (1) D. E. L. Cooke et al. Fungal Genet. Biol. 30:17, 2000. (2) J. F. Leslie and B. A. Summerell. The Fusarium Laboratory Manual, 2006. (3) T. H. Williams and P. S. W. Liu. A host list of plant diseases in Sabah, Malaysia, 1976. (4) J. R. Xu et al. Genetics 143:175, 1996.

Matched MeSH terms: Latex

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