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At least 721 records · Page 40Linked to original sources

Methemoglobinemia: an industrial outbreak among rubber molding workers.

OBJECTIVE: This case series documents an occupational outbreak of methemoglobinemia among five steam press operators at a rubber plant. Investigative findings identified the cause as repeated exposure (through manual handling) to an adhesive containing dinitrobenzene. RESULTS: The workers presented with yellow-stained hands and a variety of clinical manifestations. Methemoglobinemia levels obtained in the emergency room ranged from 3.8% to 41.2%. Methylthioninium chloride (methylene blue) rapidly reversed the cyanosis and alleviated associated symptoms in the rubber molding workers requiring treatment. CONCLUSIONS: Prompt action by plant officials and subsequent investigation by National Institute of Occupational Safety and Health/Occupational Safety & Health Administration personnel resulted in the timely and successful resolution of the problem. Individual presentations, assessment, and management are discussed along with recommendations for occupational investigation and referral.

Adult↗

Pica for foam rubber in patients with sickle cell disease.

We report three cases of pica for foam rubber among sickle cell disease patients. All three were African-American males, and at the times of initial presentation for the pica, two of them were 11 years of age and one was 15 years of age. In all cases, the pica reportedly had been occurring for at least several years. The foam rubber was most often obtained from furniture and mattresses, as well as from ironing-board pads, stereo speakers, and padded hair rollers. Reports from other researchers also suggest that this is not an uncommon type of pica. We discuss this problem from biologic, psychologic, and social perspectives.

Adolescent↗

Statistical characterization of TEM images of silica-filled rubber.

Transmission electron microscopy is used to study the micro-dispersion of silica fillers within the polymer matrix of rubber. The resulting grey-value images are interpreted as realizations of random fields and are characterized by means of variograms. The so-called Cauchy class is a suitable model for this purpose. Statistical analysis shows that different filler dispersion properties are reflected in different variogram parameters. As a case study, the random field approach is demonstrated for four exemplary rubber compounds.

Algorithms↗

Tracheal tubes in neuroanaesthesia. Nylon reinforced latex rubber tracheal tubes.

An exercise in quality assurance during neuroanaesthetic procedures identified uncontrolled re-use of armoured latex rubber tracheal tubes as a risk factor associated with equipment failure. We recommend that such tubes should be used once only. Alternatively, tubes made from more stable materials, such as polyvinyl chloride and silicone rubber, are available for clinical evaluation.

Adult↗

Anaphylaxis produced by rubber glove contact. Case reports and immunological identification of the antigens involved.

A study was carried out on six subjects suffering from anaphylactic reactions including asthma, rhinoconjunctivitis, contact urticaria and hypotension following contact with rubber gloves. All of them showed skin sensitivity and serum specific IgE to various preparations of natural latex, and not to other chemicals used in glove manufacturing. Immunoblotting techniques demonstrated that at least four soluble polypeptides from natural latex had the ability to bind specific human IgE. The results suggested that natural latex proteins present in rubber gloves can cause severe specific hypersensitivity reactions.

Adolescent↗

Effect of various irrigant and autoclaving regimes on the fracture resistance of rubber dam clamps.

Rubber dam clamps are known to break during clinical use in endodontics. This in-vitro study examined some of the variables which may contribute to the fracture. Stainless steel rubber dam clamps were subjected to various cleaning and autoclaving regimes and exposure to various solutions of sodium hypochlorite (NaOCl). Each clamp was examined after four cycles of cleaning and exposure to NaOCl. During environmental exposure to NaOCl, the clamp was stressed over a perspex rod to simulate placement onto the crown of a tooth. Clamps were examined after each test cycle visually and microscopically, or immediately after breakage. Results suggested that the fractures were because of a stress corrosion cracking phenomenon. There was evidence of intergranular and transgranular cracking of the metal. Corrosion spots were seen on the surface of the clamps and fracture occurred mainly through these spots. A number of recommendations to reduce breakage of clamps have been suggested.

Corrosion↗

Latex allergy diagnosis: in vivo and in vitro standardization of a natural rubber latex extract.

For the diagnosis of IgE-mediated (immediate) hypersensitivity to natural rubber latex (NRL), skin prick testing with extracts of latex gloves has been widely used, but such extracts are difficult to standardize. The present study aimed to produce on an industrial scale an NRL extract from freshly collected NRL and to evaluate, calibrate, and standardize the extract by both in vivo and in vitro testing. The source material, latex of the rubber tree, Hevea brasiliensis (clone RRIM 600), was frozen immediately after collection in Malaysia and shipped in dry ice to Stallergènes SA, France. Protein and allergen profiles were analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), immunoblotting, isoelectric focusing (IEF), crossed immunoelectrophoresis (CIE), and crossed radioimmunoelectrophoresis (CRIE). Allergen quantification was effected by RAST inhibition. The capacity of the preparation to elicit immediate hypersensitivity reactions in vivo was measured by skin prick testing in 46 latex-allergic patients and 76 nonallergic control subjects. SDS-PAGE and immunoblot profiles of the extract and an NRL standard (E8) provided by the US Food and Drug Administration were almost identical, disclosing several distinct IgE-binding proteins with apparent molecular weights of 14, 20, 27, 30, and 45 kDa, conforming to reported molecular weights of several significant NRL allergens. An arbitrary index of reactivity (IR) of 100 was assigned to the extract at 1:200 dilution (w/v), having a protein content of 22 micrograms/ml. Skin prick testing of latex-allergic patients and controls using the extract at 100 IR revealed 93% sensitivity, 100% specificity, 100% negative predictive value, and 96% positive predictive value. In conclusion, a skin prick test reagent for diagnosis of type I NRL allergy was successfully standardized. The reagent was demonstrated to contain most, if not all, of the currently known clinically significant NRL allergens, and it showed high sensitivity and specificity.

Adolescent↗

Tissue PO2 measured in man by an implanted latex rubber tube.

A latex rubber tube easily permeable to O2 was implanted in a triceps muscle of six volunteers. Seven days later, PO2 in muscle tissue (PtO2) was measured repeatedly by filling the tube with saline. After a 2-minute equilibration, the saline was sampled in a glass capillary and its PO2 measured by polarographic technique. PaO2 and venous oxygen tension (PvO2) were measured simultaneously. Measurements were performed under four conditions: (1) air breathing, (2) breathing 100% O2, (3) breathing 14% O2, and (4) 50 Warm exercise. During (1) breathing air PaO2 was on an average 90 mmHg, PvO2 36 MMHg and PtO2 40 mmHg. During (2) PaO2 reached 570 mmHg in 2 min, PvO2 rose slightly and PtO2 increased to 80-90 mmHg in 30-40 min. During (3) PaO2 fell rapidly to 45 mmHg and PtO2 decreased from 40 to 30 mmHg in 8 min. During (4) PaO2 did not change, PvO2 decreased slightly and PtO2 fell to approximately 30 mmHg within 2-4 min. The interindividual scatter was of equal magnitude in tissue and blood. A PtO2 higher than PvO2 during oxygen breathing and less than PvO2 during hypoxia and physical exercise is explained by the existence of oxygen gradients in the extravascular space. The present technique proved to be simple despite a 1-week delay before measurements. There were no complications, and no discomfort was complained of. Thus, the latex rubber tube seems suitable for clinical use.

Adult↗

Bile peritonitis after the use of latex rubber T-tubes.

Three cases of biliary peritonitis following the removal of a latex rubber T-tube from the common duct in the second postoperative week are reported. This is a well-recognized complication following the use of polyvinyl chloride T-tubes in biliary duct surgery, but its occurrence with latex rubber T-tubes is extremely uncommon.

Adult↗

Sensitivity to some rubber additives.

The frequency of positive patch tests to 13 rubber accelerators in Poland was recorded. Of particular interest was the relatively large group of patients positive to several, mostly chemically unrelated, accelerators. The mechanism of this multiple sensitivity is discussed. Positive tests to N-isopropyl-N-phenyl-p-phenylenediamine were observed in more than half of the patients reacting to several aromatic amines. Anamnesis indicated that in the case of cross-reactions to many aromatic amines, none of the patients positive to N-isopropyl-N-phenyl-p-phenylenediamine had complained of a reaction to rubber products.

Age Factors↗

Contact dermatitis to PPD rubber in Maleki shoes.

The Persian cloth shoe (Maleki) which has been in use for more than 800 years has a strong cloth sole and a woven cotton upper. In the last 20 years, used car tires have become readily available in Iran and the soles of some shoes are now made from these. A man with the typical picture of rubber dermatitis on the soles of his feet is described. On patch testing he gave a 2+ positive to PPD rubber and this was thought to be due to the fact that he had worn Maleki shoes for several years.

Dermatitis, Contact↗

IgE-mediated allergy to natural rubber in 30 patients with contact urticaria.

30 patients who had experienced contact urticaria after exposure to gloves, contraceptives, balloons or dental cofferdams went through a detailed examination including interviews on: exposure to rubber; local and distant symptoms; provocation tests; skin prick tests with (among other substances) latex extracts from the rubber tree Hevea brasiliensis; patch testing, IgE and RAST analyses. 23 patients (77%) reported additional symptoms from distant organs. 13 belonged to medical occupations; 25 were classified as atopics based on history; 21 had raised IgE-values; 25 were RAST-positive to the extracts from Hevea brasiliensis. 13 had a pre-existing hand dermatitis, of whom 6 were patch test positive to standard allergens. Skin prick tests with extracts from Hevea brasiliensis were the most sensitive diagnostic tool, while the RAST analysis was positive in 25/30 cases. These tests and analyses including RAST were negative in 40 control subjects. Provocation tests are of great value, but difficult to standardize. Several patients reported severe reactions at medical and dental examination/treatment situations (surgical gloves, dental cofferdams), and the risk of life-threatening anaphylactic reactions is emphasized.

Adolescent↗

Purpuric contact dermatitis from black rubber chemicals.

Black rubber chemicals are capable of causing an allergic contact dermatitis, in some cases associated with a purpuric capillaritis. A typical case of such a purpuric reaction is described in a man sensitive to black rubber chemicals.

Aged↗

Prick and use tests with 6 glove brands in patients with immediate allergy to rubber proteins.

20 patients with contact urticaria from rubber gloves were prick tested using eluates from 4 latex (Triflex, Ansell Gammex, Exona, Armi) and 2 non-latex (Tactylon, Elastyren) glove brands. All patients showed a positive prick test reaction to at least 2 latex glove eluates. A hypoallergenic glove (Ansell Gammex) gave a positive prick test reaction in 1 patient, but non-latex gloves were negative in all cases. All patients showed a positive result in the use test with a latex surgical glove (Triflex), whereas none did with a non-latex glove (Tactylon). Non-latex gloves and, in some cases, also hypoallergenic latex gloves, are a good alternative to rubber gloves for patients with immediate latex allergy.

Adult↗

Extraction of mercaptobenzothiazole compounds from rubber products.

At evaluation of contact dermatitis caused by solid material, patch testing is usually performed with the material as such and with extracts of it. In this study, optimization of the extraction technique monitored by quantitative HPLC analysis of the extracted haptens is described for mercaptobenzothiazole derivatives. Several solvents with different properties are included. Acetone has traditionally been a solvent widely used for the extraction of organic haptens from solid products. However, acetone and other ketones are not inert solvents. The rubber accelerators 2-(4-morpholinyl mercapto) benzothiazole (MMBT) and N-cyclohexyl-2-benzothiazyl sulfenamide (CBS) react with acetone, yielding 2 new compounds, which were isolated and characterised by NMR and MS. For the extraction of solid rubber products, methyl tert-butyl ether (MTBE) was found to be a more suitable solvent which is unreactive to most common haptens.

Antifungal Agents↗

Brain and central nervous system cancer mortality in U. S. rubber workers.

Since 1963 the observed mortality experience of BCNS cancers among rubber workers appears to be very comparable to that expected. A possible exception to this statement is the experience of one plant in Akron, Ohio, reported by Monson and Nakano. Excesses in earlier years may also be localized to one or two companies. The results of a case-control study did not support a hypothesized association of elevated BCNS cancer risk with exposures in the tire building/tire assembly segments of the rubber tire manufacturing process. The direction of future epidemiologic studies would benefit by the assembly of as large a number of cases as possible and should focus on calendar periods of exposure, make allowance for a latent period, and include retrospective industrial hygiene assessments of the specific exposures.

Adult↗

Silicone rubber: a new diffusion property useful for general anesthesia.

Ether, nitrous oxide, halothane, and cyclopropane diffuse through silicone rubber. General anesthesia can be produced in dogs by passing the vapors of any of these anesthetic agents through a coil of silicone rubber tubing, each end of which is placed in an artery and vein. Potential applications include a new method for general anesthesia and a simple accurate vaporizer for halothane.

Anesthesia, General↗