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Results for “LUBRICATION”

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At least 397 records · Page 22Linked to original sources

PubMed1993

HIV infection in European female sex workers: epidemiological link with use of petroleum-based lubricants. European Working Group on HIV Infection in Female Prostitutes.

OBJECTIVES: To assess the prevalence of and risk factors associated with HIV infection in European female sex workers, particularly sexual risk factors. DESIGN: Multicentre cross-sectional study performed in nine European countries. METHODS: Female sex workers voluntarily enrolled between September 1990 and November 1991. Face-to-face interviews were conducted in various settings (health care, prostitute organizations, outreach) to collect information on over 150 behavioural, health and sociodemographic variables. Enrollment of intravenous drug users (IVDU) was limited to a maximum of 25% of the total sample. The HIV-1 and HIV-2 antibody status of blood or saliva samples was tested using enzyme-linked immunosorbent assay and confirmed by Western blot. RESULTS: Eight hundred and sixty-six (91.6%) of the 945 interviewees provided blood (n = 824) or saliva (n = 42) samples. HIV seroprevalence was 5.3% [44 HIV-1-positives and two HIV-2-positives (from Lisbon)] overall, 31.8% (35 out of 110) in IVDU and 1.5% (11 out of 756) in non-IVDU [odds ratio (OR), 31.6; P < 0.001]. Lack of condom use (P = 0.002, test for trend) and previous ulcerative sexually transmitted disease (OR, 3.6; P = 0.06) were associated (on logistic regression) with HIV infection in both IVDU and non-IVDU. Previous hepatitis B (OR, 13.8; P = 0.02) and needle-sharing (OR, 4.1; P = 0.04) were associated with HIV infection in IVDU, and low education level (P = 0.02, test for trend), previous transfusion (OR, 9.1; P = 0.003), origin from sub-Saharan Africa (OR, 5.4; P = 0.05) and use of petroleum-based lubricants (OR, 15.2; P = 0.001) in non-IVDU. CONCLUSIONS: HIV prevalence remains relatively low among non-IVDU prostitutes in Europe. While intravenous drug use remains the most important risk factor for HIV, petroleum-based lubricants (used by 10% of women in this study) may be a risk factor for HIV among European female sex workers; over 80% of those interviewed always used condoms with clients.

Adolescent↗

PubMed1997

Boundary lubrication between the tendon and the pulley in the finger.

The lubrication mechanism between the human flexor digitorum profundus tendon and the A2 pulley was investigated in vitro. The gliding resistance at the interface between the tendon and the pulley increased significantly after the tendon had been treated with a hyaluronidase solution. Alcian-blue staining of the surface of the tendon before and after it was treated with hyaluronidase suggested the presence of hyaluronate complex. Alcian blue-positive and hyaluronidase-sensitive materials, such as hyaluronate or proteoglycan, in the synovial membrane and the matrix of the tendon, may act as a boundary lubricant, facilitating the gliding and reducing the resistance between the tendon and the pulley.

Alcian Blue↗

PubMed2026

Wickerhamomyces anomalus Pseudo-Outbreak Associated with Medical Lubricating Gel, South Africa, 2023-2024.

A nationwide investigation identified 426 patients with Wickerhamomyces anomalus fungal cultures in South Africa; most cases clustered during May-November 2023. Case-patients lacked evidence of infection, indicating a pseudo-outbreak. Genomic and laboratory analyses implicated contaminated sterile lubricating gel. A nationwide product recall resulted in a decline in reported cases.

South Africa↗

PubMedDate not supplied

Evaluation of the dermal carcinogenicity of lubricant base oils by the mouse skin painting bioassay and other proposed methods.

Lubricant base oils are petroleum products that are predominantly derived from the vacuum distillation of crude oil. Various types of refinement can be employed during the manufacturing process, and evidence suggests that certain of the associated process streams produce skin cancer. Polycyclic aromatic compounds (PACs), some of which are considered as the causative agents, are removed, concentrated or chemically converted during the refinement process. In order to understand the effects of various types of refinement processes on carcinogenic potential, 94 oils were evaluated in the mouse epidermal cancer bioassay. This Exxon database is unique, because of the wide range of crude oils and processing histories represented. Seven processing history classifications are described, and conclusions concerning the impacts of each refinement process on dermal carcinogenicity are discussed. This research also included an evaluation of selected biological and chemical test methods for predicting carcinogenic potential. These included a modified version of the Ames test for mutagenicity, as well as analytical characterizations of the polycyclic aromatic structures in the oils. For classification purposes, a sample was considered to be carcinogenic if it resulted in the production of two or more tumor-bearing animals (in test groups of either 40 or 50 animals). The modified Ames test was considered to be positive if the mutagenicity index was > or = 2.0, and PAC analyses were similarly designated as positive or negative according to proposed guidelines. All of the alternative test methods showed similar agreement with dermal carcinogenicity bioassay data; concordance values were > or = 80%. However, each test was incorrect in ca. 10%-20% of the cases evaluated.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

The effect of additive hyaluronic acid on animal joints with experimentally reduced lubricating ability.

A series of in vitro experiments demonstrated a clear effect of additive hyaluronic acid (HA) on animal joints with experimentally reduced lubricating ability. Eleven canine hip joints were utilized and the experimental conditions tested were: i) intact joints, ii) after washing the joint surfaces, and iii) after adding 1% HA to them. The frictional coefficient of every joint increased after washing and subsequently decreased after adding HA. The mean values were 0.007 (SD 0.004) on the intact joints, 0.020 (SD 0.009) after washing, and 0.013 (SD 0.005) after the addition of HA. The differences between the three values of frictional coefficients were shown to be statistically significant (p < 0.01).

Animals↗

PubMed2004

Influence of additive hyaluronic acid on the lubricating ability in the temporomandibular joint.

In synovial fluid, hyaluronic acid (HA) is an essential component for the lubrication of joints, thus preventing friction. The relationship between HA and joint friction is not unambiguously established yet. In the present study, the effect of the application of HA on the frictional coefficient in the temporomandibular joint was evaluated. After measuring the frictional coefficient in intact porcine joints (n = 10), the subsequent effect of phosphate-buffered saline (PBS) washing and gauze scouring and the application of HA was examined. Compared with the intact joint, the frictional coefficient was significantly larger after PBS washing and gauze scouring. Subsequent application of HA resulted in a significant decrease (50-75%) of the frictional coefficient. However, it did not recover to the same value as in the intact joints. Observations by scanning electron microscopy showed that after PBS washing, the amorphous layer of the articular cartilage was still intact, whereas it was partially collapsed after gauze scouring. In conclusion, the addition of HA did reduce the coefficient of friction under the experimental conditions in this study; the relevance to the clinical condition and the duration of the treatment effect in vivo require further investigation.

Algorithms↗

PubMed1978

Effects of compression force, particle size, and lubricants on dissolution rate.

The effects of compression force, particle size, and lubricant concentration on the dissolution rates of compressed disks of salicylic acid, aspirin, and an equimolar mixture of aspirin and salicylic acid were investigated. Compression forces from 450 to 9100 kg had no effect on dissolution rates. With 5% starch incorporated into an equimolar mixture of aspirin and salicylic acid, the dissolution rates were independent of compression forces from 910 to 9100 kg. A 10-fold change of particle size of the materials being compressed did not affect the dissolution rates. An increase in the concentration from 0.1 to 5% of calcium stearate, glyceryl monostearate, magnesium stearate, and stearic acid progressively slowed the dissolution rate. An increase in the concentration from 0.1 to 5% talc and polyethylene glycol 4000 did not affect the dissolution rates. An increase in the concentration of starch from 0.1 to 5% progressively increased the dissolution rates.

Aspirin↗

PubMed1996

Utilization and degradation of an ester-based synthetic lubricant by Acinetobacter lwoffi.

An oil-degrading bacterium, Acinetobacter lwoffi, isolated by elective culture from the Medway estuary, utilized an ester-based synthetic lubricating oil EMKARATE DE 155 as sole carbon and energy source. Analysis of culture supernatants by gas chromatography showed the accumulation of a nondegradable metabolite 1,1,1 Tris (hydroxymethyl)propane in addition to two metabolizable fatty acids, octanoic and decanoic acids as products of the synthetic oil degradation. Esterase activities were subsequently demonstrated in oil and acetate-grown cells. The synthetic oil therefore appears to be partially biodegradable in the environment.

Acinetobacter↗

PubMed1992

Ocular lubricants and intraocular stray light.

The question was raised whether ocular lubricants or artificial tears might have adverse effects on optical clarity of the eye. Eight current commercial products were tested on five young subjects, using the Straylight Meter. No adverse effects were found.

Adult↗

PubMed1989

In vitro characterization of human salivary lubrication.

The friction coefficients for parotid and submandibular-sublingual salivas of 7 subjects were measured. At the load and speeds used, the lubricatory properties of the secretions followed the McKee-Petroff's curve. The friction coefficients for both secretions approximated those reported for boundary and thin film lubrication.

Adolescent↗

PubMed1990

A new assessment in vitro of human salivary lubrication using a compliant substrate.

The lubrication effect of salivary secretions was assessed in terms of separating a rigid object from a compliant substrate. There was little difference among the various secretions of a single donor. The viscosity of salivas increased as a function of time. Neither the friction testing nor viscometry provided an adequate model of the tissue-coating function ascribed to saliva.

Adult↗

PubMed1990

Investigation of used synthetic lubricants by computerized gas chromatography/mass spectrometry.

The chemical fractions of a used, synthetic lubricating oil for petrol engines were separated by flash chromatography on a silica gel column using variable mixtures of hexane/chloroform as eluents. The products extracted in the most polar fraction were separated by gas chromatography and then analyzed by computerized mass spectrometry. The analytical method used allowed the identification, among the various compounds, of a family of tetrahydropyran homologues with an aminic chain, phthalates, thiophene and pyridine derivatives. The presence of these structures, some of which are of toxicological interest, was also shown by infrared spectra.

Esters↗

PubMed1994

Environmental health aspects of lubricant additives.

This paper describes briefly the industrial hygiene aspects of the manufacture and use of lubricant additives and gives some details concerning the acute, chronic and environmental toxicity of important additive types. It also addresses the need to communicate information about product hazards and draws attention to some special points of concern which the additives industry in general has with existing and developing environmental health regulations. Finally, it takes a crystal ball to the long-term future of additives manufacture.

Animals↗

PubMed1994

Health, safety and environmental aspects of used crankcase lubricating oils.

This paper indicates the health, safety and environmental concerns which have been expressed regarding the handling, re-use and disposal of used crankcase lubricating oils and discusses the factors which are believed to these concerns. It also indicates the current and developing situation with regard to legislation in this area, discusses briefly the disposal of used oils in cement kilns and sets out the views of the industry sectors most involved. Finally, it describes the simple safeguards the adoption of which should enable these materials to be handled with a high degree of safety.

Environmental Health↗

PubMed1986

Long-term peritoneal tissue response in rats to mould-release agents and lubricant powder used on surgeons' gloves.

Following implantation of 50-mg samples of a starch powder used for glove lubrication, or of talc or calcium carbonate mould-release agents for gloves, in the peritoneal cavity of rats, the treated animals were killed in groups of ten after 2, 4, 8, 13, 26 and 52 wk and were examined. Groups of sham-operated animals were used as controls. Within each treatment group the frequency of peritoneal adhesions remained constant throughout the study. Talc produced significantly more adhesions than the other treatments and caused a more severe granulomatous reaction, which persisted. Calcium carbonate and starch powder produced similar numbers of adhesions and in both cases the residues became invested by a thin fibrous capsule. Calcium carbonate appeared a safer material than talc.

Animals↗

PubMed2006

Transesterification of canola oil in mixed methanol/ethanol system and use of esters as lubricity additive.

Transesterification of canola oil was carried out with methanol, ethanol, and various mixtures of methanol/ethanol, keeping the molar ratio of oil to alcohol 1:6 and using KOH as a catalyst. Mixtures of alcohol increased the rate of transesterification reaction and produced methyl as well as ethyl esters. The increased rate was result of better solubility of oil in reaction mixture due to better solvent properties of ethanol than methanol and equilibrium due to methanol. With 3:3 molar ratio of methanol to ethanol {MEE (3:3)} the amount of ethyl ester formed was 50% that of methyl ester. Properties (acid value, viscosity, density) of all esters including mixed esters were within the limits of ASTM standards. Lubricities of these esters are in the order: ethyl ester>methyl ethyl ester>methyl ester.

Esterification↗

PubMed2005

Characterization of lubricity improver additive in diesel by gas chromatography-mass spectrometry.

The characterization of lubricity improver additives by GC-MS-SIM is an important tool for the development and monitoring of new formulations as well as for quality control of additives in diesel. A simple method for the quantification of a linoleic oil additive derivative in diesel has been developed. Calibration is performed by analysis of standard solutions containing 2-hydroxy-ethyl linoleate with pentadecanoyl propanoate as the internal standard. The proposed method permitted the quantification of the linoleate ester at a concentration of 300 microg/mL in the additived diesel. The recovery of additive and the repeatability of the quantitative results are evaluated.

Calibration↗

PubMed2007

Clinical discussion on the relative efficacy of 2 surfactant-containing lubricating agents in removing proteins during contact lens wear.

BACKGROUND: This clinical study aims to evaluate the clinical efficacy of 2 popular rewetting agents, Blink-N-Clean, manufactured by Advanced Medical Optics (Santa Ana, California), and Clens 100, manufactured by Alcon (Ft. Worth, Texas), on protein removal in a nonsymptomatic population of contact lens wearers fitted with etafilcon A soft contact lenses, Acuvue 2, manufactured by Vistakon, a division of Johnson and Johnson Vision Care (Jacksonville, Florida). METHODS: This randomized, double-blind, crossover study was performed on 22 subjects who had been fitted successfully with etafilcon A soft contact lenses. Each subject was examined on 3 occasions, at 2-week intervals, to evaluate a number of clinical signs related to contact lens wear, with or without the use of ocular lubricants specifically designed to reduce the levels of proteins adsorbed on the lens. A washout period was observed between each of the study's different phases. High- and low-contrast visual acuity levels were measured using the Bailey-Lovie (logMAR) chart under mesopic and scotopic conditions. Protein levels adsorbed on the lenses were determined using a modified Lowry method. Ocular health was assessed under biomicroscopy using conventional techniques. Subjective comfort was also evaluated, using a questionnaire based on a Likert scale graded from 0 to 50. RESULTS: Objectively, no significant difference in either visual acuity or comfort was found between the use or the nonuse of drops or the use of one specific product. Using Clens 100 allowed for a significant reduction in the quantity of protein on the lens surface. More than 3 subjects of 4 (77%) preferred the Clens 100 product, in large part because they found the size of drops dispensed from the Clens 100 bottle less disturbing during insertion because of the size of the drops and blur. CONCLUSION: Among healthy contact lens wearers fitted with the same type of contact lens, a significant difference was observed in the quantity of proteins adsorbed on the lens with the use of Clens 100, as compared with the use of either Blink-N-Clean or no product at all. This difference does not seem to have had an impact because clinical signs and symptoms did not vary over the course of the study.

Adult↗