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At least 37 records · Page 2Linked to original sources
PubMed1979

Rubber sump drainage of enterocutaneous fistulae.

Effective sump drainage of high enterocutaneous fistulae, together with alimentary rest and total parenteral nutrition, is now an integral part of the modern management of patients with this condition. The low tissue reactivity of the plastic and polymer materials currently used in most drainage tubes appears however, to be counterproductive to the establishment of a discrete fistula track and control of the fistula. A case is made for the use of red rubber sump drains for enterocutaneous fistulae. The greater tissue reactivity of rubber is reviewed and confirmed by animal experimentation. A method of rubber sump drainage of enterocutaneous fistulae developed during the management of 83 such fistulae is described.

Animals↗
PubMed1976

Chemistry of rubber processing and disposal.

The major chemical changes during the processing of rubber occur with the breakdown in mastication and during vulcanization of the molded tire. There is little chemical change during the compounding, calendering, extrusion, and molding steps. Reclaiming is the process of converting scrap rubber into an unsaturated, processible product that can be vulcanized with sulfur. Pyrolysis of scrap rubber yields a complex mixture of liquids, gas, and residue in varying ratios dependent on the nature of the scrap and the conditions of pyrolysis.

Carbon↗
PubMed1977

Rubber band ligation of haemorrhoids. Analysis of 281 patients.

The problems and discomfort resulting from haemorrhoidectomy have led to the development of other forms of therapy. Rubber band ligation has become a popular method of treatment for internal piles. The results are comparable with those achieved by excisional surgery. The material consists of 281 consecutive patients with internal haemorrhoids treated with rubber band ligation. The average follow-up was 12 months. 239 of the 262 patients re-examined were entirely free of discomfort (91%). In all the eight cases with mucosal prolapse the ligation was not successful. In these as well as in patients with rubber allergy, other forms of treatment are suggested.

Adult↗
PubMed1976

In vivo degradation of silicone rubber poppets in prosthetic heart valves.

Dynamic shear modulus G' was measured throughout the volume of three nonvariant silicone rubber poppets which were recovered from aortic prosthetic heart valves that had been implanted for 4 days, 52 days, and 8 years. Similar measurements were obtained for two unused silicone rubber poppets. Although the recovered poppets exhibited no obvious physical evidence of damage, the silicone rubber had undergone in vivo degradation throughout the poppet volume as indicated by decreases in modulus. The measurements also indicate that the poppet surface degrades at a rate faster than the core. Further, comparison with data reported in the literature suggests that the surfaces of variant poppets degrade at a rate faster than the surfaces of nonvariant poppets.

Aortic Valve↗
PubMed1976

Thin rubber sheeting in frontal sinus surgery: animal and clinical studies.

Closure of the nasofrontal communication is the most common cause of failure of nonobliterative external of nonobliterative external frontal sinus operations for chronic sinus disease. To determine whether silicone rubber sheeting or tubing might prevent closure, we designed animal experiments and conducted a clinical study. We enlarged the nasofrontal duct in dogs, inserted silicone rubber tubing or sheeting and assessed ductal patency grossly and microscopically. The tubes prevented epithelization and failed to prevent local osteoblastic reaction, fibroplasia, and scar formation. In contrast, sheeting permitted rapid mucosal regeneration, less osteoblastic activity, and less fibrosis. Our 16 patients with chronic sinus disease underwent a modified Lynch operation, with enlargement of the nasofrontal duct and stenting with rubber tubes or sheeting. The sheeting provided the best long-term result. In our experience, it raised the success rate of the classic Lynch external operation.

Adolescent↗
PubMed1975

Respiratory tract disease from thermosetting resins. Study of an outbreak in rubber tire workers.

An outbreak of upper and lower respiratory tract inflammatory disease and conjunctivitis among synthetic rubber tire workers occurred. The outbreak began after the introduction of a new thermosetting resin, containing resorcinol and a trimere of methylene aminoacetronitrile, into the rubber tire carcass stock formulation. Two hundred ten workers were affected. Characteristically, symptoms improved during periods of sick leave or vacation, recurring upon the workers' return to the plant. Chest radiograms disclosed pneumonic infiltrates in about one fourth of the cases. Pulmonary function studies detected abnormal airways dynamics as well as abnormal diffusing capacity in more than one third of the workers tested. Lung biopsy showed evidence of focal interstitial fibrosis and peribronchiolar and perivascular chronic inflammatory reaction. The illness was ascribed to volatile products released during the manufacture of synthetic rubber tires. The exact chemical nature of these products is unknown.

Adult↗
PubMed2026

A STORM-based protocol for nanoscale imaging and quantitative analysis of protein-associated and phospholipid-associated structures in natural rubber.

Stochastic Optical Reconstruction Microscopy (STORM) enables nanoscale mapping of molecular components beyond the diffraction limit; however, its reproducible implementation in hydrophobic polymer matrices remains challenging because fluorescence-labeling specificity, fluorophore photoswitching, three-dimensional localization, chromatic registration, and quantitative image analysis must be carefully controlled. This protocol presents a standardized experimental workflow for dual-color labeling, astigmatism-based three-dimensional STORM acquisition, and quantitative analysis of protein-associated and phospholipid-associated structures in natural rubber (NR). The workflow covers sample pretreatment, Cy5 NHS ester labeling of protein-associated primary amines, DiI labeling of phospholipid-rich domains, STORM imaging-buffer preparation, three-dimensional single-molecule localization, dual-channel registration, generation of standardized xy projections, aggregate-size analysis, and projected lateral spatial correlation assessment. Reproducibility is supported by defined acquisition and localization criteria, three independent sample preparations with at least five fields of view analyzed per condition, and unlabeled, single-color, dye-only matrix, and processing-associated Cy5 controls. Mean lateral localization precisions of 11.8 ± 2.3 nm for Cy5 and 13.5 ± 2.9 nm for DiI were obtained, while two-dimensional Fourier ring correlation analysis of the xy projections yielded effective lateral image resolutions of approximately 25 and 28 nm, respectively. Image-based particle segmentation and localization-coordinate-based density-based spatial clustering of applications with noise (DBSCAN) were applied to standardized xy projections as complementary quantitative approaches. Application of the protocol to untreated, centrifuged, and protease-treated NR samples demonstrated treatment-associated changes in the detected abundance and projected size distributions of protein- and phospholipid-associated aggregates, together with a non-monotonic change in their projected lateral spatial correlation. These observations describe alterations in nanoscale organization but do not, by themselves, establish stable protein-phospholipid complex formation. Unlike previous studies that primarily demonstrated the feasibility of STORM imaging in rubber materials, the principal contribution of this work is an end-to-end, step-by-step protocol incorporating defined controls, three-dimensional localization, image-quality metrics, chromatic-registration procedures, and complementary quantitative-analysis pipelines for non-expert users. The workflow may be adaptable to other hydrophobic polymers and soft-material systems after appropriate optimization and validation.

Rubber↗
PubMed2025

Loss and recovery dynamics of mitochondria in laticifer vessels of the rubber tree under repeated latex harvesting.

Natural rubber is harvested by periodically incising the laticifer vessels in the bark of rubber trees to release latex, the cytoplasm of laticifers. Although mitochondria are suspended in the cytoplasm and were expected to leak out, some earlier studies failed to detect their presence. In this study, we identified mitochondria and plastids in expelled latex using molecular methods and confocal microscopy, quantifying their abundance at 13 850 ± 800 mitochondria per microliter latex. Each tapping event released approximately 746 ± 35 mtDNA copies and 113 ± 7 mitochondria per laticifer cell (mean cell volume: 0.008134 μl). Individual mitochondria contained 6.7 ± 0.6 genome copies (mean ± SD), a value significantly higher than the 1.5 ± 0.2 mtDNA copies per mitochondrion observed in leaves. This suggests that laticifer mitochondria are primed for proliferation. We further investigated mitochondrial dynamics during tapping cycles by measuring temporal changes in concentration. Initial latex flow exhibited the highest mitochondrial concentration (18 749 ± 954/μl), which progressively decreased to 40% of the initial level (7542 ± 940/μl) within 30 min, likely due to dilution from water influx. Following latex vessel plugging, the mitochondrial population rebounded rapidly, surpassing the initial concentration by 1.4-fold within 3 days. Subsequent tapping cycles (second and third) exhibited similar mitochondrial loss and recovery trends, though recovery kinetics shifted from a linear (first cycle) to a logarithmic pattern. These results indicate that tapping stimulates mitochondrial proliferation and that laticifer mitochondria lack protective mechanisms comparable to those of the nucleus, resulting in their expulsion with latex during harvesting.

Hevea↗
PubMed1975

Long term review of the results of rubber band ligation of haemorrhoids.

A long term assessment (mean 4.8 years) of the value of rubber band ligation treatment for haemorrhoids has been obtained by a questionnaire answered by 125 of 147 patients. Eighty-nine per cent of patients were cured or satisfied with the results of treatment, although complete absence of symptoms was only obtained in 44 per cent. Further conservative treatment (rubber band ligation or manual dilatation) was required in 12 per cent and only 3 (2 per cent) have had a haemorrhoidectomy. Similar results were obtained for patients with the additional symptoms of pain and irritation, the presence of large skin tags and for the majority of third degree piles.

Dilatation↗
PubMed1975

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↗
PubMed1978

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↗
PubMed1976

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↗
PubMed1977

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↗
PubMed1979

N-nitrosamines in the rubber and tire industry.

Airborne N-nitrosomorpholine (0 to 27 micrograms per cubic meter) was found in two of four rubber industry factories. N-Nitrosodimethylamine was also found in two factories, but at lower levels. These findings may be relevant to the reported increased risk of certain types of cancer in rubber workers in some of the same areas where the N-nitrosomorpholine levels were highest.

Air Pollutants↗
PubMed1976

Methane fermentation of rubber (Hevea brasiliensis) latex effluent.

Four species of bacteria capable of CH4 fermentation of rubber latex effluent were isolated and identified as a Methanococcus, a strain of M. vannielii, a Methanobacterium and a strain of M. omelianskii. Auxanographic tests using the four strains showed growth and CH4 formation on a basal medium containing mineral salts or added H2 and Co2. Varied response was obtained when the basal medium was added to formate, acetate, butyrate, methanol, ethanol, and glucose. Previous work has established acid fermentation of Hevea latex arising from bacterial contamination and decomposition of the non-rubber constituents which consist of N-compounds, 2% quebrachitol, and smaller concentration of carbohydrates. This suggests that reduction of CO2 and fermentation of acids formed during metabolism of Hevea latex are possible pathways of CH4 production.

Acetates↗
PubMed1976

Chronic diseases in the rubber industry.

An overview is presented of epidemiologic studies of chronic diseases in the rubber industry. Analyses of the mortality experience during the period 1964-1972 of workers age 40-64 and retirees age 65-84 of two large rubber and tire manufacturing companies consistently disclosed excesses of deaths attributed to leukemia and lymphosarcoma, and for cancers of the stomach, large intestine, and prostate. The relation of site-specific malignancies to work histories and grouped occupational titles as surrogate measures of work-related exposures to possible carcinogens is described. There was no evidence of company-wide, sizable, consistent excess for the other major chronic diseases causes of death. Although a total cohort deficit in the mortality rate for lung cancer was found, there was a history of increased frequency of exposure to certain work areas among lung cancer decedents. Morbidity studies, including analysis of disability retirements, and ad hoc questionnaire and health testing surveys, disclosed excesses of chronic pulmonary diseases. There was evidence of an interactive effect in the association of work and smoking histories with pulmonary disability retirement.

Adult↗