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At least 217 records · Page 12Linked to original sources

PubMed1997

Randomized, prospective, double-blind study of the effects on pain perception of lidocaine jelly versus plain lubricant during outpatient rigid cystoscopy.

PURPOSE: There is no clear evidence that intraurethral lidocaine jelly decreases pain and/or makes rigid cystoscopy more tolerable for patients. Since lidocaine jelly is significantly more expensive than plain lubricant, we attempted to assess the true benefit of this agent. MATERIALS AND METHODS: We performed a randomized, prospective, double-blind study to compare the anesthetic effects of intraurethral 2% lidocaine jelly versus plain lubricant in patients undergoing rigid cystoscopy. Unlike previous studies, we ensured adequate urethral filling by using 30 cc of each agent and we waited 20 minutes after instillation of the agent before performing cystoscopy to allow adequate absorption. Cystoscopy was performed using a 17 to 21F rigid instrument. A total of 189 patients was entered into the study but 10 were excluded from analysis due to incomplete questionnaires. A 10-point scale (1-least to 10-most painful) was used to measure pain perception. RESULTS: In men pain perception was significantly decreased when lidocaine jelly was used (mean plus or minus standard error 3.00 +/- 0.21 versus 4.36 +/- 0.37 points, p = 0.002). In women there was no observed difference in pain perception when lidocaine jelly or plain lubricant was used (3.21 +/- 0.38 versus 3.11 +/- 0.30 points, p = 0.823). Patient race, performance of a related procedure, cystoscope size or history of cystoscopy did not significantly affect reported pain scores. There was a slight decrease in pain perception with increasing age (-0.23 +/- 0.10 points per decade, p = 0.021). The level of patient anxiety before cystoscopy was also significantly associated with pain perception (p < 0.001). CONCLUSIONS: Lidocaine jelly offers no advantage over plain lubricant in regard to pain control during rigid cystoscopy in women. However, when used in adequate amounts and allowed to dwell in the urethra for 20 minutes before cystoscopy, lidocaine jelly can significantly decrease pain in men.

Adult↗

PubMed1996

Sore throat with the laryngeal mask: does the lubricant matter?

In daily anesthetic practice, the insertion of a Laryngeal Mask--airway is facilitated by means of a lubricant. Many different products are in widespread clinical use, according to personal preference or what's in or on the anesthesia trolley. This study compares four different lubricants: Xylocaine 10% spray, Silkospray, Endosgel and water. When comparing the ease of insertion of the Laryngeal Mask, the genuine lubricants proved to be superior to water. However, no single lubricant was associated with a statistically significant lower incidence of postoperative sore throat.

Anesthetics, Local↗

PubMedDate not supplied

Surfactant barrier lining peritoneal mesothelium: lubricant and release agent.

OBJECTIVE: Five studies are described to determine whether there is an outermost lining of surface-active phospholipid (SAPL) adsorbed to the peritoneum and to quantify its ability to act as a release (antistick) agent and boundary lubricant by standard tests. METHODS: Using a hydrophobic probe (phosphin E), epifluorescence microscopy was used to demonstrate an outermost lining of oligolamellar SAPL by spectral analysis of the emitted light, a finding consistent with the appreciable hydrophobicity demonstrated on canine peritoneal mesothelium and its virtual elimination by incubation with bile salt. Good release and excellent lubricating capabilities of human peritoneal SAPL have been quantified as the release factor and coefficient of friction, respectively, by standard tests from the physical sciences. RESULTS: A well-defined outermost layer was clearly visible on peritoneal mesothelium whose color spectrum was identical to that produced by pure phosphatidylcholine ultrasonicated into its oligolamellar state. Further evidence for a SAPL lining was demonstrated by a parietal contact angle of 43 degrees (47 degrees visceral) on this surface and its virtual elimination by incubation with dilute bile salt. Human SAPL from continuous ambulatory peritoneal dialysis (CAPD) effluent proved an effective release agent, reducing adhesion by 67%, and an excellent lubricant as quantified by a coefficient of friction of 0.091 under load (1.9 kg/cm2). CONCLUSIONS: The good release and excellent lubricating properties of SAPL adsorbed to mesothelial surfaces are highly desirable in reducing wear and exfoliation of epithelial cells. In spanning epithelial cells, the same lining might also serve to render tight junctions tight and reduce macromolecular escape while compatible with many aspects of CAPD, including lipid permeability and conflicting results obtained from administering exogenous SAPL.

Animals↗

PubMed2001

Study on the lubrication mechanism of natural joints by confocal laser scanning microscopy.

Natural joints have an excellent lubricating function, but the detailed mechanism is still unclear. To clarify this lubricating mechanism, we observed the behavior of the cartilage surface under the physiological loading condition with confocal laser scanning microscopy in normal and osteoarthritis (OA) cartilage rabbit specimens. Even with a considerable loading condition, in both natural and OA cartilage, the fluid pool area coexisted with the direct contact area. In the junction from the direct contact area to the fluid area, there was a third area with a liquid-crystal arrangement. In OA cartilage, these areas were generally irregular and small. These results suggest that a lubrication system in the fluid phase, such as squeeze film lubrication, might work under severe pressure in normal cartilage, and hyaluronic acid macromolecules in the synovial fluid might form a liquid-crystal structure and support pressure on the cartilage surface, whereas these systems did not affect the OA cartilage.

Animals↗

PubMed1998

Induction of peroxisomal oxidases in mussels: comparison of effects of lubricant oil and benzo(a)pyrene with two typical peroxisome proliferators on peroxisome structure and function in Mytilus galloprovincialis.

Marine mussels are used as bioindicators of water pollution in marine and estuarine environments in the so-called "Mussel Watch" programs because of their capacity to accumulate numerous organic xenobiotics including aromatic hydrocarbons. In this study, we have analyzed the effects of two xenobiotics [benzo(a)pyrene and the water accommodated fraction of a lubricant oil] and two typical (rodent) peroxisome proliferators (clofibrate and dioctyl phthalate) on structure and function of peroxisomes in digestive glands of mussels Mytilus galloprovincialis, either following water exposure (for 1, 7, and 21 days) or after direct injection through the adductor muscle (for 1 and 7 days). The activities of catalase (CAT), acyl-CoA oxidase (AOX), and D-amino acid oxidase were determined in whole homogenates of digestive glands. In addition, stereological methods were applied on sections stained histochemically for demonstration of catalase activity in order to quantify the morphological changes of peroxisomes. The peroxisomal acyl-CoA oxidase and D-amino acid oxidase were increased in mussels injected for 7 days with benzo(a)pyrene, phthalate, and clofibrate and a similar trend was noted for benzo(a)pyrene and lubricant oil in water exposure experiments (21 days). The catalase activity was reduced or unchanged depending on the mode of exposure of animals. By stereology, significant increases of numerical and volume densities of peroxisomes were found in animals injected for 7 days with lubricant oil or clofibrate. These observations indicate that peroxisomal oxidases in mussels are induced at moderate rates in response to different xenobiotics and that their determination could provide a (sensitive) marker for detection of effects of some toxic pollutants, particularly the lubricant oils which in addition induce significant structural alterations of mussel peroxisomes.

Animals↗

PubMed1989

Lubrication of selected salivary molecules and artificial salivas.

The lubrication regime displayed by human salivas (parotid and submandibular-sublingual), purified salivary molecules (the mucins MG1 and MG2 and alpha-amylases), and selected artificial salivas (Oracare D, Saliva Substitute, and Orthana) was assessed in vitro using a friction-testing device. Thin-film (boundary) lubrication was observed for all of the salivary samples and two of the artificial salivas examined. Oracare D, a glycerol-based artificial saliva, was the exception since it lubricated by a thick-film (hydrodynamic) regime. On a molar basis, the best lubricants of the purified salivary molecules were MG1 greater than MG2 approximately nonglycosylated alpha-amylases approximately glycosylated alpha-amylases.

Amylases↗

PubMed1976

The effect of vaginal lubricants on Neisseria gonorrhoeae.

The possible interference of vaginal lubricants in culture diagnosis of gonorrhea was investigated by studying in vitro effect of selected lubricants on Neisseria gonorrhoeae. Two lubricants widely used in family planning and other clinics were demonstrated to have a bactericidal effect on N. gonorrhoeae when tested with more than one method. Gonococci were killed on contact with Lubrifoam, even at a 10 per cent concentration, and an exposure time as short as one minute was sufficient to inhibit the growth on chocolate agar medium. The K-Y jelly showed less inhibitory effect than Lubrifoam. These findings suggest that certain vaginal lubricants have bactericidal effects and their presence can inhibit the growth of Neisseria gonorrhoeae.

Neisseria gonorrhoeae↗

PubMedDate not supplied

Vasoactive intestinal polypeptide (VIP) provokes vaginal lubrication in normal women.

The human vagina is known to be heavily innervated by vasoactive intestinal polypeptide (VIP) immunoreactive nerve fibres. In the present study we have examined the effect of VIP (900 pmol x kg-1 x h-1, IV during 30 min) on vaginal lubrication and blood flow in fourteen normal non-pregnant women. Vaginal blood flow was measured by the heat clearance technique and the vaginal lubrication quantified by the weight gain of preweighed filter papers placed on the surface of the vaginal wall for 30 min. Arterial blood pressure, pulse frequency and the concentration of VIP in peripheral blood were monitored. VIP (median concentrations of 200-300 pmol x l-1) induced a significant increase in vaginal blood flow accompanied by a 100% increase in vaginal lubrication (from 27 mg/cm2 to 53 mg/cm2). The VIP infusion lead to a significant increase in pulse frequency and a significant fall in diastolic arterial blood pressure. The findings suggest that VIP may participate in the control of the local physiological changes observed during sexual arousal: genital vasodilation and increase in vaginal lubrication.

Adult↗

PubMed2004

The ecotoxicology of vegetable versus mineral based lubricating oils: 3. Coral fertilization and adult corals.

Biodegradable vegetable-derived lubricants (VDL) might be less toxic to marine organisms than mineral-derived oils (MDL) due to the absence of high molecular weight aromatics, but this remains largely untested. In this laboratory study, adult corals and coral gametes were exposed to various concentrations of a two-stroke VDL-1A and a corresponding MDL to determine which lubricant type was more toxic to each life stage. In the fertilization experiment, gametes from the scleractinian coral Acropora microphthalma were exposed to water-accommodated fractions (WAF) of VDL-1A and MDL for four hours. The MDL and VDL-1A WAFs inhibited normal fertilization of the corals at 200 microg l(-1) total hydrocarbon content (THC) and 150 microg l(-1) THC respectively. Disturbance of a stable coral-dinoflagellate symbiosis is regarded as a valid measure of sub-lethal stress in adult corals. The state of the symbiosis in branchlets of adult colonies of Acropora formosa was monitored using indicators such as dinoflagellate expulsion and dark-adapted photosystem II yields of dinoflagellate (using pulse amplitude modulation fluorescence). An effect on symbiosis was measurable following 48 h exposure to the lubricants at concentrations of 190 microg l(-1) and 37 microg l(-1) THC for the MDL and VDL-1A respectively. GC/MS revealed that the main constituent of the VDL-1A WAF was the compound coumarin, added by the manufacturer to improve odour. The fragrance containing coumarin was removed from the lubricant formulation and the toxicity towards adult corals re-examined. The coumarin-free VDL-2 exhibited significantly less toxicity towards the adult corals than all of the other oil types tested, with the only measurable effect being a slight but significant drop in photosynthetic efficiency at 280 microg l(-1).

Animals↗

PubMed2006

Impact of molecular structure on the lubricant squeeze-out between curved surfaces with long range elasticity.

The properties of butane (C4H10) lubricants confined between two approaching solids are investigated by a model that accounts for the curvature and elastic properties of the solid surfaces. We consider the linear n-butane and the branched isobutane. For the linear molecule, well defined molecular layers develop in the lubricant film when the width is of the order of a few atomic diameters. The branched isobutane forms more disordered structures which permit it to stay liquidlike at smaller surface separations. During squeezing the solvation forces show oscillations corresponding to the width of a molecule. At low speeds (<0.1 ms) the last layers of isobutane are squeezed out before those of n-butane. Since the (interfacial) squeezing velocity in most practical applications is very low when the lubricant layer has molecular thickness, one expects n-butane to be a better boundary lubricant than isobutane. With n-butane possessing a slightly lower viscosity at high pressures, our result refutes the view that squeeze-out should be harder for higher viscosities; on the other hand our results are consistent with wear experiments in which n-butane were shown to protect steel surfaces better than isobutane.

Journal Article↗

PubMed2006

Friction laws for lubricated nanocontacts.

We have used friction force microscopy to probe friction laws for nanoasperities sliding on atomically flat substrates under controlled atmosphere and liquid environment, respectively. A power law relates friction force and normal load in dry air, whereas a linear relationship, i.e., Amontons' law, is observed for junctions fully immersed in model lubricants, namely, octamethylciclotetrasiloxane and squalane. Lubricated contacts display a remarkable friction reduction, with liquid and substrate specific friction coefficients. Comparison with molecular dynamics simulations suggests that load-bearing boundary layers at junction entrance cause the appearance of Amontons' law and impart atomic-scale character to the sliding process; continuum friction models are on the contrary of limited predictive power when applied to lubrication effects. An attempt is done to define general working conditions leading to the manifestation of nanoscale lubricity due to adsorbed boundary layers.

Journal Article↗

PubMed2002

Effects of ovariectomy and estrogen and androgen treatment on sildenafil-mediated changes in female genital blood flow and vaginal lubrication in the animal model.

OBJECTIVE: Our purpose was to investigate the effects of ovariectomy and estradiol and testosterone treatment on sildenafil- induced changes in genital hemodynamics and vaginal lubrication. STUDY DESIGN: Female New Zealand White rabbits were either kept intact or underwent ovariectomy. Two weeks after ovariectomy, animals were treated with vehicle, testosterone, or a combination of estradiol and testosterone for 14 days. Genital hemodynamics and vaginal lubrication were recorded at the end of the treatment period. RESULTS: Ovariectomy caused a marked decrease in vaginal lubrication but did not significantly alter genital hemodynamics. In contrast to testosterone treatment of ovariectomized animals, estradiol treatment significantly increased genital blood flow and vaginal lubrication above that observed in control animals. Sildenafil administration caused a significant increase in genital hemodynamics irrespective of the hormonal status. CONCLUSION: This study suggests that estradiol but not testosterone modulates genital hemodynamics and that sildenafil enhances genital blood flow irrespective of hormonal status.

Animals↗

PubMed2003

Effects of ovariectomy and estrogen replacement on basal and pelvic nerve stimulated vaginal lubrication in an animal model.

The goal of this study was to investigate the effects of ovariectomy and estrogen replacement on vaginal tissue integrity and vaginal lubrication in basal conditions and in response to pelvic nerve stimulation (PNS). Two weeks after ovariectomy, female New Zealand White rabbits were administered vehicle or estradiol (200 micrograms/day) for an additional 2 weeks. Ovariectomy caused significant vaginal atrophy and diminished vaginal lubrication in the basal state and after PNS, compared to intact controls. Estrogen replacement normalized lubrication values and tissue wet weight to control levels. In conclusion, vaginal tissue integrity and lubrication are diminished by ovariectomy and are normalized by estrogen replacement.

Animals↗

PubMed1997

A preliminary assessment of intra-oral lubricating systems for dry mouth patients.

OBJECTIVE: To provide extended intra-oral delivery of a saliva substitute. INTERVENTION: Three different types of prostheses containing saliva substitute were designed and assessed: a two-part device resembling a mandibular complete denture sealed by cobalt-samerium magnets, a one-part clear resin device for the edentate patients and a flexible mouth guard type of appliance containing a lubricant releasing bubble for the dentate patients. SETTING: A teaching hospital Oral Medicine and Rheumatology Clinic. SUBJECTS: 8 edentate and 3 dentate Sjogren Syndrome sufferers. OUTCOME MEASURES: Subjective dryness after a week of wearing the lubricating appliance. RESULTS: The majority of the subjects wore the appliances for 6-12 hours during each 24 hours. The initial dryness severity diminished after wearing the lubricating prosthesis. The patients preferred to wear the appliance at night. CONCLUSION: All criteria were fulfilled on designing a saliva substitute lubricating appliance and some of the subjects have worn this prosthesis successfully for up to 3 years. Particular benefit was obtained by night-time wear.

Aged↗

PubMedDate not supplied

Subjective and clinical evaluation of oral lubricants in xerostomic patients.

The purpose of this investigation was to evaluate and compare four oral lubricants in relation to oral mucosal status, perceived relief of dry mouth symptoms, and patient acceptance. Three commercial oral lubricants--two sprays and one gel--and a home remedy of margarine were evaluated. Twenty-five xerostomic/salivary gland dysfunctional patients demonstrating < 0.20 mL/min of unstimulated whole saliva participated in the randomized, four-phase, cross-over study. Each phase included a ten-day use of oral lubricants, followed by a four-day washout period. On the first and tenth days of use, lip and buccal mucosa dryness and perceived oral dryness were evaluated. Patient acceptance of the oral lubricant was evaluated at the end of each ten-day period. The Wilcoxon matched-pairs signed-rank test was used to analyze data over time and between-group differences. The gel group reported a statistically significant improvement in perceived oral dryness from Day 1 to Day 10. No other significant within-group differences were found. Subjects rated the gel significantly better than margarine for convenience, perceived value, minutes of relief, and in the "overall" rating. No other significant between-group differences were noted.

Administration, Topical↗

PubMed1992

Characterization of a bovine synovial fluid lubricating factor. II. Comparison with purified ocular and salivary mucin.

Boundary lubricating activity and biochemical characteristics of purified lubricating factor from bovine synovial fluid (PSLF) were compared to those of mucinous glycoprotein from human submandibular saliva and stimulated tears. Mammalian synovial fluid and saliva contain mucinous glycoproteins which reduce the coefficient of friction (mu) in a bearing of latex:glass which isolates boundary lubrication. In contrast, mucin secreted by the lacrimal gland did not lubricate. Cleveland plotting showed that these species are not identical.

Animals↗

PubMed1992

Characterization of a bovine synovial fluid lubricating factor. III. The interaction with hyaluronic acid.

Although hyaluronate is not a boundary lubricant in cartilaginous and latex:glass bearings, a distinct interaction with purified synovial lubricating factor (PSLF) was demonstrated by three means: 1) enhancement of lubricating ability in an artificial test system; 2) viscometry; 3) electron microscopy. The interaction was of a physical rather than a specific chemical type; it varied with the degree of purification of PSLF and of hyaluronate. The interaction accounts for retention of the relatively small PSLF molecule (approximately 280 kDa) with the synovial mucin on a 0.22 microns filter. The data provide evidence that hyaluronate and PSLF act synergistically in the boundary lubricating activity of animal joints.

Animals↗

PubMed2006

Intrarectal administration of lidocaine gel versus plain lubricant gel for pain control during transrectal ultrasound-guided extensive 10-core prostate biopsy in Hong Kong Chinese population: prospective double-blind randomised controlled trial.

OBJECTIVE: To compare the level of pain experienced by patients during transrectal ultrasound-guided prostatic biopsy using intrarectal 2% lidocaine gel versus plain lubricant gel. DESIGN: Prospective double-blind randomised controlled trial. SETTING: Regional hospital, Hong Kong. PATIENTS: From March 2002 to December 2003, patients who underwent ultrasound-guided prostate biopsy at a Geriatric Urology Centre. MAIN OUTCOME MEASURES: Pain and discomfort scores measured by horizontal visual analogue scales. RESULTS: A total of 338 consecutive patients were randomised to lidocaine gel or plain lubricant gel groups. The two groups were statistically similar in demographic and disease characteristics. There were no significant statistical differences in pain or discomfort score in the lidocaine gel and plain lubricant groups--pain score: 1.75 versus 1.79 (P=0.66) on day 0 and 0.21 versus 0.15 (P=0.97) on day 1; discomfort score: 0.79 versus 0.77 (P=0.86) on day 0 and 0.12 versus 0.12 (P=0.76) on day 1. No major complications were recorded in this cohort. CONCLUSIONS: Transrectal ultrasound-guided trucut biopsy of the prostate can be safely performed with no anaesthesia in Chinese patients. Pain and discomfort are minimal. It was found that 2% lidocaine gel has no statistical therapeutic or analgesic benefit over plain lubricant gel.

Administration, Rectal↗