Latex Material Research Articles

Analysis of mitochondrial DNA damage using 8-hydroxy 2′deoxyguanosine on in vitro and in vivo exposure of biomaterials

The present study was carried out to evaluate the effect of HAP-EVA, fibrin glue, HA-BG, Latex and Dental material on oxidative stress related mtDNA damage by in vitro and in vivo methods. In vivo studies of these biomaterials were carried out by implanting biomaterials (five materials) on animals for period of 1, 4, 12, 26 and 52 weeks. At the end of observations, animals were anesthetized, sacrificed and tissues surrounding the implanted materials were collected. Brain, bone and muscles were used for the extraction of mtDNA. Similarly mtDNA was extracted from the homogenate of fresh brain, bone and muscles on exposure to the physiological saline extract of all the above five biomaterials (In vitro). The extracted mtDNA were subjected to analyse the presence of 8-OHdG. The results of study indicated that there was no significant increase in the level of 8-OHdG and thereby does not influence on the GC-TA transversions.

Effect of latex material on antioxidant enzymes, lipid peroxidation, DNA damage, and chromosomal aberration

Cell integrity is affected by oxidative stress when the production of active oxidants overwhelms antioxidant defense mechanisms. Latex, a natural polymer obtained from Hevea brasiliensis, is used in medical industry for manufacturing surgical gloves, urinary catheters, and dental dams. The aim of this study was to evaluate the effects of latex material on oxidative stress by in vivo and in vitro methods. In addition, the material was screened for its ability to induce any chromosomal aberrations (CAs) by in vitro method. In vivo studies were carried out with implanted latex material onto subcutaneous tissue of various batches of experimental Wistar rats. At the end of experimental period, animals were anesthetized, blood was collected for serum analysis, and sacrificed. Liver was excised for the determination of antioxidant enzymes and lipid peroxidation (LPO). Subcutaneous tissues were obtained for the extraction of genomic DNA from implanted animals and checked for the presence of 8-hydroxy-2-deoxyguanosine (8-OHdG), considered an indicator of DNA damage. Simultaneously, in vitro studies were carried out using fresh liver and subcutaneous tissue obtained from Swiss albino mice treated with physiological saline extract of latex material. For the estimation of both in vitro and in vivo oxidative stress, 10% liver homogenate was assessed for stress indicators like reduced glutathione, glutathione reductase, glutathione peroxidase, LPO and protein content. The results of both in vivo and in vitro studies indicated that the chemical leachents from the latex material did not significantly affect LPO and the levels of antioxidant enzymes. There was also no significant increase in 8-OHdG content due to the presence of implanted latex material. Finally, the results of in vitro CA test and G banding indicated that extracts of test material did not induce any chromosomal abnormalities.

Affection of Manufacture Parameters and Mixture Material on Plastic Alloy Bearings

Manufacture process parameters will be obtained from experiments in research. Molding technology determines the mechanical properties and performance of the product. The influence of molding temperature and time are significant on the performance of water lubricated bearing, the plastic alloy is based on latex material, synthesized with different fillings, accelerators and other matters, and displays great mechanical and friction properties. The main performance included peel strength, tensile strength and wearing capacity. Optimization of manufacture process parameters and the orthogonal experiments on them were carried out by integrating the results of experiments and finally the optimal manufacture process was achieved. In the experiment, three-leveled orthogonal tests were conducted for the three systems to test the tensile strength, tearing strength, stress at definite elongation, hardness and tensile rate. The impacts of the respective systems were analyzed and the content of each component are determined to get the optimal formula.

A Study on the Modification of Water Lubrication Bearing Materials

Water lubricated bearings differ from water lubricated bearings in its special choice of material. A novelty material developed with an aim to improve the lubricating performance and bearing capacity, water lubricated bearings BTG plastic alloy is based on latex material, synthesized with different fillings, accelerators and other matters, and displays great mechanical and friction properties. In order to expand its application to the field of water lubrication, a bettered formula was adopted from the aspects of vulcanization, reinforced filling and softened plastification systems to improve its mechanical property. In the experiment, three-leveled orthogonal tests were conducted for the three systems to test the tensile strength, tearing strength, stress at definite elongation, hardness and tensile rate. The impacts of the respective systems were analyzed and the content of each component are determined to get the optimal formula. The modified bearings enjoy some mechanical properties that live up to or even exceed American military standards MIL-B-17901(Vessel).

Allergenic compounds on the inner and outer surfaces of natural latex gloves: MALDI mass spectrometry and imaging of proteinous allergens

Natural latex gloves are the cause of a severe health problem to an increasing number of healthcare workers or patients due to the presence of protein allergens as Hevein or Rubber Elongation Factor (REF). One of the most challenging problems is the in situ localization of theses allergens in, e.g. gloves, to estimate the allergenic potential of the latex material. A sample preparation protocol applying a binary matrix-assisted laser desorption/ionization(MALDI) matrix containing alpha-cyano-4-hydroxy cinnamic acid (CHCA) and 2,5-dihydroxy benzoic acid (DHB) on trifluoro acetic acid (TFA) etched latex glove surfaces allowed the direct determination (exact molecular weight) of Hevein, REF and a truncated form of REF (tREF) within nine different brands of natural latex gloves by means of MALDI-TOF-MS in the linear mode. MALDI mass spectrometry demonstrated that Hevein, tREF and REF were present on the inner surfaces (in direct contact with the skin) of many, but not all, investigated gloves without any prior extraction procedure. Additionally, different isoforms of the allergen Hevein were detected (exhibiting ragged C-termini). tREF and REF could always be detected beside each other, but were not observed on every latex glove sample, which contained Hevein. It was also demonstrated that there is a significant difference in terms of proteins and polymers between inner and outer surfaces of gloves, which helps to explain the different allergenic potential of these.MALDI imaging allowed for the first time the unambiguous localization of all three allergens in parallel and showed that Hevein was present on 36% of the investigated area of a latex glove with a certain localization, whereupon, tREF and REF were only found on 25% of the investigated material.

Why are arteries the size they are?

sones and shirey ([12][1]) performed the first coronary artery angiogram by accident in 1958. While injecting contrast material for a left ventricular angiogram, the catheter slipped out of the ventricle and into the right coronary artery. Sones immediately recognized the advantage of visualizing

Vascular Preservation During Arthroscopic Osteoplasty of the Femoral Head-Neck Junction: A Cadaveric Investigation

The goal of this study was to evaluate the risk of vascular injury with arthroscopic osteoplasty of the femoral head-neck junction in a cadaveric model. Eight fresh-frozen cadaveric pelvi were used for arthroscopic osteoplasty of a predetermined 150 degrees arc of resection along the anterior femoral head-neck junction. Postoperatively, injection studies of the deep femoral arteries were performed on all specimens to identify local extravasation of neoprene latex before polymerization as a reproducible indicator of vascular injury. Control specimens included 1 specimen without an osteoplasty and 1 specimen after an "aggressive" open osteoplasty with intention to violate the superior retinacular vessels. The first control specimen showed complete filling of the superior retinacula branches, whereas the second control specimen had evidence of intracapsular latex extravasation. In 7 of 8 experimental specimens, there was near-to-complete filling of the superior and inferior retinacula branches with no signs of latex extravasation. In 1 specimen, no superior retinacular branches were identified; however, no extravasation of the latex material was noted. No injury to the main extracapsular branches of the medial or lateral femoral circumflex vessels was noted. We noted on average 3 superior retinacular vessels penetrating the posterior-superior head-neck junction. There was no evidence of vascular injury to the main blood supply of the femoral head in any of the 8 experimental specimens as noted by latex extravasation. These findings show that arthroscopic osteoplasty can be performed without disrupting the vascular supply to the femoral head. This article has important information on the relation of vascular structures and the resection limit with arthroscopic osteoplasty of the femoral head-neck junction.

Recycling of NR based cured latex material reclaimed with 2,2′-dibenzamidodiphenyldisulphide in a truck tire tread compound

It is observed that reclamation of natural rubber latex based rubber using 2,2'-dibenzamidodiphenyldisulphide as reclaiming agent is an optional methodology for recycling of waste latex rubber (WLR). For progressive replacement of virgin natural rubber by the reclaim, two alternatives curing system were investigated: adjustment or reduction of the curing system with increasing reclaim content, to compensate for the extra amount of curatives brought along by the reclaim. For fixed curing system, as if the reclaim were equivalent to virgin NR. The cure behavior, final crosslink density and distribution, mechanical properties, and dynamic viscoelastic properties of the blends with reclaimed WLR are measured and compared with the virgin compound. The morphology of the blends, sulfur migration, and final distribution are analyzed. The mechanical and dynamic viscoelastic properties deteriorate for both curing systems, but to a lesser extent for fixed curing system compared to adjusted curing system. With the fixed cure system, many properties like tensile strength and compression set do still deteriorate, but tan δ and M300/M100, representative for the rolling resistance of tires are improved. On the other hand, with the adjusted cure system both mechanical and dynamic properties still deteriorate.

Effect of styrene and methyl methacrylate comonomers in ethyl acrylate/methacrylic acid latex on particle alkali-swellability, film formation and thickening with associative thickeners

Series of emulsion copolymers were synthesized from methacrylic acid, ethyl acrylate as a “soft” comonomer and different amounts of methyl methacrylate or styrene as “hard” comonomers. It was shown that the extent of particle swelling and hydroplasticization at constant content of methacrylic acid was affected by the “hard” comonomer content due to its polarity. The minimum film forming temperature (MFT) results were found to be in good agreement with the titration curves, with zeta-potential measurements and with the flow behavior of the copolymer latices. Viscosity increase caused by particle swelling strongly influences thickening of latex material also being dependent on the comonomer polarity.

Controlled, radical reversible addition–fragmentation chain‐transfer polymerization in high‐surfactant‐concentration ionic miniemulsions

AbstractLiving free‐radical polymerization of methacrylate and styrenic monomers with ionic surfactants was carried out with reversible addition–fragmentation chain transfer in miniemulsion with different surfactant types and concentrations. The previously reported problem of phase separation was found to be insignificant at higher surfactant concentrations, and control of the molar mass and polydispersity index was superior to that of published miniemulsion systems. Cationic and anionic surfactants were used to examine the validity of the argument that ionic surfactants interfere with transfer agents. Ionic surfactants were suitable for miniemulsion polymerization under certain conditions. The colloidal stability of the miniemulsions was consistent with the predictions of a specific model. The living character of the polymer that comprised the latex material was shown by its transformation into block copolymers. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 960–974, 2004

Permeability of different types of medical protective gloves to acrylic monomers

Dental personnel and orthopedic surgeons are at risk when manually handling products containing methyl methacrylate (MMA). Dental products may also contain cross-linking agents such as ethylene glycol dimethacrylate (EGDMA) or 1,4-butanediol dimethacrylate (1,4-BDMA). Skin contact with monomers can cause hand eczema, and the protection given by gloves manufactured from different types of material is not well known. The aim of this study was to determine the breakthrough time (BTT, min) as a measure of protection (according to the EU standard EN-374-3) for a mixture consisting of MMA, EGDMA and 1,4-BDMA. Fifteen different gloves representing natural rubber latex material, synthetic rubber material (e.g. nitrile rubbers), and synthetic polymer material were tested. The smallest monomer MMA permeated within 3 min through all glove materials. A polyethylene examination glove provided the longest protection period to EGDMA and 1, 4-BDMA (> 120 min and 25.0 min), followed by the surgical glove Tactylon (6.0 min and 8.7 min) and the nitrile glove Nitra Touch (5.0 min and 8.7 min). This study showed that the breakthrough time (based on permeation rate) cannot be regarded as a 'safe limit'. When the permeation rate is low, monomers may have permeated before BTT can be determined. Using double gloves with a synthetic rubber inner glove and a natural rubber outer glove provided longer protection when the inner glove was rinsed in water before placing the outer glove on top.

Anaphylactic reaction after artificial insemination

Bovine seroalbumin is known as an allergen for human beings, but reactions to it in an artificial insemination procedure are much rarer. We report a case of anaphylaxis after intrauterine insemination (IUI) in which sensitization to bovine serum albumin (BSA) is demonstrated. Report the allergy evaluation performed in a patient who suffered a severe reaction immediately after an IUI procedure. A 33-year-old woman was referred because of an anaphylactic reaction after a second trial of IUI. She developed pruritus, abdominal pain, nausea and vomiting, bronchospasm, and generalized urticaria. She had an atopic medical history of pollen allergy and sensitization to cat epithelium. She had never had trouble with minor surgery and she usually uses latex material. She had never received heterologous sera before. Her husband's semen for the IUI was processed in a standard fluid medium called upgraded INRA B 2 (Laboratoires CCD, Paris, France), which contains amino acids, lipids, vitamins, BSA, penicillin, and streptomycin in addition to inorganic salts. Skin prick tests with the medium and BSA 10 mg/mL were positive. In vitro studies demonstrated an immunoglobulin E binding protein of 60 to 65 kDa and mast cells and basophil activation (CD63 expression) against BSA contained in the medium. Cutaneous and challenge tests with penicillin and streptomycin were negative. We consider the BSA in the semen culture medium to be the factor which triggered the anaphylactic reaction. This case supports the authors who state that media free from heterologous proteins should be used for human application, especially on atopic patients, to avoid sensitization.

Combined ultrasonic toothbrush module

A U-shaped, ultrasonic toothbrush module to be used with currently available ultrasonic toothbrush hand pieces made of soft thermoplastic, silicone, or latex material with upper and lower bridge receiving spaces formed on opposite sides. The receiving spaces are designed to receive a user's upper and lower bridges when placed into the user's mouth. Disposed on the three inside surfaces of each receiving space are a plurality of bristles which completely contact the exposed surfaces of every tooth when the device is used. The module includes a housing with a pivoting T-shaped member and magnets attached at one end that connects to a standard ultrasonic toothbrush hand piece. Motion generated by the hand piece is transmitted through the T-shaped member and to the U-shaped member. The movement of the U-shaped member generates ultrasonic waves that are transmitted to the surfaces of the teeth and move the brushes when teeth are placed into the upper and lower bridge receiving spaces.

Controlled, micro‐scale film formation of waterborne dispersions

AbstractThe film formation on a micro‐scale of latex material is described. Waterborne polymer dispersions dried below their Tg are treated by laser or direct heat treatment by means of a tip (diameter 5 µ m) of a micro thermal analysis apparatus (µ ‐TA). Both methods give a linewidth, line thickness and dot‐sizes in the micron range. The layer thickness decreases during fusion of the particles because of the loss of voids during film formation. Non treated areas can be washed away selectively. Laser treatment gives a more smooth surface than direct thermal treatment with a µ‐TA tip. Copyright © 2001 John Wiley & Sons, Ltd.

Living Radical Polymerization in Miniemulsion Using Reversible Addition−Fragmentation Chain Transfer

Living radical polymerizations using reversible addition−fragmentation chain transfer (RAFT) have been conducted successfully in miniemulsions stabilized by nonionic surfactants. The miniemulsion stability was found to be a key issue. Both anionic and cationic surfactants were not able to maintain the original droplet morphology during the reaction. The application of nonionic surfactants allowed the controlled polymerization of methacrylate and styrene monomers, resulting in stable dispersions free of coagulate. Typical particle sizes for these latices were around 200−300 nm. The molar mass of the polymer was close to the predicted value, and polydispersity was typically below 1.20, never exceededing 1.40. The “living” character of the latex material was further exemplified by its transformation into block copolymers. The increased polymerization rate of the compartmentalized system allowed for improved block copolymer purity compared to that of homogeneous systems. Furthermore, it was shown that latex b...

Degradation of Latex and of Natural Rubber by Streptomyces Strain La 7

Streptomyces strain La 7 was isolated from the banquete of a city high way in Karlsruhe. According to partial 16S rRNA gene sequencing it was identical with Streptomyces albogriseolus and Streptomyces viridodiastaticus. DNA-DNA-similarity studies revealed 80.3-82.4% similarity between each of two of the three strains. Although phylogenetically closely related, Streptomyces strain La 7 differed from the two reference strains by morphological as well as physiological features and might represent a new species aside of S. albogriseolus and S. viridodiastaticus. The new Streptomyces strain La 7 was grown in a medium containing a latex emulsion or squares of natural rubber gloves as the only carbon source. On agar plates with a latex overlay agar, translucent halo formation around the colonies was observed. The unvulcanized latex was metabolized and the carbon from the isoprene units was apparently used for cell growth. In shake cultures with unlimited oxygen supply, during 60 days of incubation, 140 mg of the 175 mg totally emulgated latex were degraded exponentially. In sterile control flasks about 3% of the initial amount of latex could not be recovered after incubation on a shaker, presumably due to photochemical transformation. During static incubation of sterile medium, the latex formed a sticky layer at the surface of the medium and on the glass walls and recovery of the material was more difficult. Estimation of the protein content of cells from total nitrogen resulted in about 50% of the degraded latex being incorporated into cells, if a standard cell composition was assumed. Direct protein analysis according to Bradford (1976) gave much lower estimates, presumably due to a low content of aromatic amino acids. Stripes of natural rubber were degraded by Streptomyces strain La 7 during 70 days to an extent of about 30%. Scanning electron microscopy demonstrated, that hyphes of Streptomyces strain La 7 colonized and penetrated the latex surface with a concomitant deterioration of the latex material.

In situ localization of latex allergens in 3 different brands of latex gloves by means of immunogold field emission scanning and transmission electron microscopy

Background: Latex proteins represent relevant allergens, particularly for those persons who are frequently exposed to latex products (eg, health care workers and patients with chronic disorders). Although several latex allergens have been characterized by biochemical and molecular biologic techniques, little information is available concerning the in situ localization of allergenic proteins in latex products. Objective: The objective of the present study was the in situ localization of latex allergens. Methods: Serum IgE from patients with latex allergy reacting with a broad range (5-200 kd) of latex allergens was used for the in situ localization of latex allergens. One surgical and 2 examination latex glove brands were investigated by using immunogold field emission scanning and transmission electron microscopy. Results: Allergens were detected on the inner and outer surface of the gloves, particularly near the edges, crests, or folds of the bleb-like structures visible on the surface of the latex material at high magnifications. In ultrathin cross-sections, latex allergens were found throughout the sections. Conclusions: Latex allergens were localized on the outer and inner surface but also in the interior of latex gloves. The occurrence of latex allergens on the surface of latex products may be related to their potential to induce local reactions and, perhaps, to sensitize individuals by means of contact. (J Allergy Clin Immunol 2000;105:561-9.)

An anatomical study of the arteries feeding the triceps brachii muscle of swine.

The arterial vascular network of the porcine triceps brachii muscle (TBM) (an extensor muscle to the forearm) was studied and compared to another extensor muscle (the soleus muscle) of small rodents. The left axillary arteries (LAA) of nine Yucatan miniature swine were perfused with latex material to reveal the organization of the arterial blood supply to the TBM. Blood is supplied to the TBM by the main branches of the LAA. Some of the branches end in one of the four heads of the TBM. Other branches continue to bifurcate further and to supply blood to adjacent muscles. The feed arteries (FAs) arise as side-branches at regular distances from the branches of the LAA. The mean number of FAs per TBM was 109.7 and the mean diameter was 388 microns. The distribution of FAs to the muscle area is heterogenous. Most FAs penetrate the epimysium of the TBM on its medial aspect. It appears that more FAs come out of the branches of LAA that end in the TBM as compared to arteries which continue to bifurcate away from TBM. FA diameters were in the range of 300 microns. This study is the first necessary step towards understanding the distribution of oxygen and nutrients to the porcine skeletal muscle. It reveals the presence of a more complicated vascular network than that observed previously in small laboratory animals.

Detection of IgE antibodies to latex allergens in human serum.

Reports indicate increasing incidence of Type I allergic reactions to latex allergens. The proteins that act as allergens and produce such allergic reactions are found in the natural latex sap of Hevea brasiliensis. All those who are exposed to latex products, particularly healthcare workers, are potentially at risk. The lack of qualified allergen extracts makes it difficult to perform skin testing on individuals who are at high risk. Therefore, a reliable in vitro test system for the detection of IgE antibodies to latex would be of considerable utility. We have developed a serological test for the qualitative determination of specific IgE antibodies to latex. In our study, 75 sera from individuals with a history of latex allergy and 29 serum samples from healthcare workers were tested by both radioimmunoassay (RIA) and enzyme immunoassay (EIA). The allergen bound to paper discs was the same solid phase for the RIA and EIA assays. The allergen preparation used for coating the paper discs was a mixture of proteins obtained from raw latex. The data show a good correlation between the results of RIA and EIA methods with data obtained using an RIA assay at an independent laboratory and by skin prick testing. Comparing the performance of our test using our latex material with that of the latex material obtained from the Food and Drug Administration (FDA), along with results of other tests including skin tests, we found that the specificity and sensitivity of our assay method approaches 100%. The data show no significant cross-reactivity between latex and banana. A low level of cross-reactivity between latex and avocado was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Crystal Adherence to Urinary Catheter Materials in Rats

Crystal adherence to the surfaces of indwelling urinary catheter materials was investigated by scanning electron microscopy and immunofluorescence method. Small sterile disks were inserted into the rat bladder transvesically. Crystals were frequently associated with fibrillar material, some of which was believed to be fibrin. Increases in fibrillar materials were paralleled by increases in crystal adherence. On the other hand, a decrease in the amount of fibrin adhering to the surfaces of heparinized material, resulting in a decrease in the quantity of encrusting deposits on these materials, was found as compared with other catheter materials, including latex, silicone and nonheparinized material. These findings suggest that early adherence of fibrin to the surfaces of indwelling urinary catheter materials plays an important role in the development of crystal adherence and encrustation on catheter materials. It is also suggested that heparin inhibits the adherence of fibrin, resulting in decreased encrustation on the surfaces of the heparinized material.