PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “HYALURONIC ACID”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 433 records · Page 24Linked to original sources
PubMed1975

Studies on the generation of hydrogen peroxide during some non-enzymic reactions changing the hyaluronic acid molecule.

The effect of catalase on non-enzymic-induced changes in the conformation of hyaluronic acid in a vitreous humour preparation was measured using viscometry. Ascorbate, heavy metal ions, riboflavin or EDTA all lowered the viscosity of hyaluronic acid solutions. These effects could be prevented by the addition of catalase. This suggested that H2 O2 is produced by these compounds and that the resulting change in conformation of hyaluronic acid may be due to peroxyl and hydroxyl attack by the free radicals thus generated.

Animals↗
PubMed2000

Mechanism of hyaluronan binding and degradation: structure of Streptococcus pneumoniae hyaluronate lyase in complex with hyaluronic acid disaccharide at 1.7 A resolution.

Hyaluronic acid (HA) is an important constituent of the extracellular matrix; its bacterial degradation has been postulated to contribute to the spread of certain streptococci through tissue. Pneumococci and other streptococci produce hyaluronate lyase, an enzyme which depolymerizes HA, thus hyaluronate lyase might contribute directly to bacterial invasion. Although two different mechanisms for lyase action have been proposed, there was no crystallographic evidence to support those mechanisms. Here, we report the high-resolution crystal structure of Streptococcus pneumoniae hyaluronate lyase in the presence of HA disaccharide product, which ultimately provides the first crystallographic evidence for the binding of HA to hyaluronate lyase. This structural complex revealed a key interaction between the Streptococcus peneumoniae hyaluronate lyase protein and the product, and supports our previously proposed novel catalytic mechanism for HA degradation based on the native Streptococcus peneumoniae hyaluronate lyase structure. The information provided by this complex structure will likely be useful in the development of antimicrobial pharmaceutical agents.

Binding Sites↗
PubMed1978

Characterization of proteoglycan and the proteoglycan--hyaluronic acid complex by electric birefringence.

An electric field causes partial alignment of macromolecules in a dilute solution. The accompanying changes in the solution birefringence offer a sensitive and quick means of monitoring the rates of particle orientation and hence the size of the solute molecules. Such measurements are reported for dilute solutions of proteoglycans in the absence and presence of added hyaluronic acid. The proteoglycan molecules are shown to be some 580 nm long. In the presence of hyaluronic acid they form aggregates that appear to be consistent with the model previously proposed in which the proteoglycans attach radially to the extended hyaluronic acid chain. The electric-birefringence relaxation rates indicate aggregates of similar length to that of the extended hyaluronic acid chain, with the proteoglycans spaced on average at 29nm intervals. A proteoglycan sample the cystine residues of which had been reduced and alkylated showed no evidence of aggregation with hyaluronic acid up to the concentrations of the acid corresponding to 1% of the total uronic acid content. The electric-birefringence method is shown to have a large potential in the study of associating polysaccharide solutions.

Alkylation↗
PubMed1994

The extracellular matrix of the fetal wound: hyaluronic acid controls lymphocyte adhesion.

Adhesive interactions between lymphocytes and components of the extracellular matrix (ECM) within a wound environment play a crucial role in determining the inflammatory response following tissue injury. In fetal wounds the extracellular matrix is composed predominantly of hyaluronic acid. Within this environment the inflammatory reaction as a result of injury is minimal. We propose that this lack of an inflammatory cell response in the fetal wound is due to the high levels of hyaluronic acid within the ECM and the inability of lymphocytes to adhere to this matrix component. Therefore, we examined the adhesive properties of fetal lymphocytes to fibronectin, vitronectin, collagen types I, III, IV, V, and hyaluronic acid--ECM components involved in fetal and adult wound environments. Fetal lymphocytes from both spleen and thymus demonstrated significant binding capabilities to fibronectin, vitronectin, and collagen types I and III. No intrinsic binding capabilities were detected to hyaluronic acid. Adhesion was not affected by the addition of IL-1, IFN-gamma, or phorbol dibutyrate. The inability of lymphocytes to adhere to hyaluronic acid helps to explain the lack of inflammation found in fetal wounds and serves to demonstrate the importance of ECM-lymphocyte interactions in determining the inflammatory response during fetal wound healing.

Animals↗
PubMed1980

The inability of superoxide dismutase to inhibit the depolymerization of hyaluronic acid by ferrous ions and ascorbate.

Superoxide radicals were investigated as to their capability of depolymerizing the hyaluronic acid of the bovine vitreous body. Using viscometry it was found that O2 radicals, generated by the hypoxanthine/xanthine oxidase method or the combination of NADH and phenazine methosulphate, degraded hyaluronic acid. This reaction was suppressed by superoxide dismutase, catalase, and peroxidase. In contrast, the depolymerization of hyaluronic acid by oxidation-reduction systems like ascorbic acid or ferrous ions was abolished by catalase and peroxidase while superoxide dismutase showed no effect.

Animals↗
PubMed1974

X-ray fibre diffraction of cartilage proteoglycan aggregates containing hyaluronic acid.

Ordered conformations of proteoglycan-hyaluronic acid aggregates in the intercellular matrix in cartilage were observed by X-ray diffraction. The sodium salt form of three samples, (a) aggregated proteoglycan, (b) disaggregated proteoglycan and (c) reconstituted disaggregated proteoglycan, give essentially similar X-ray fibre-type diffraction photographs. The patterns correlate with the chondroitin 4-sulphate component and can be interpreted as twofold helical conformations, similar to that observed previously for the free acid form of chondroitin 4-sulphate (Isaac & Atkins, 1973). The information takes us one step nearer the situation found in cartilage in vivo.

Animals↗
PubMed2004

[Effect of the hyaluronic acid on tracheal healing. A canine experimental mode].

Several drugs have been used to modulate of the tracheal healing process in order to prevent tracheal stenosis. Hyaluronic acid (HA) is a modulator of the fibrogenesis. In this work we evaluate the effect in order the application of hyaluronic acid has on tracheal healing, after cervical tracheoplasty in dogs. A cervical tracheal resection and tracheoplasty was performed in 12 dogs and they were treated following surgery as follows: Group I (n = 6) Topical application of normal saline solution (0.9%) on the anastomosis site. Group II Topical application of hyaluronic acid on the trachea anastomosed. The animals were evaluated clinical, radiological and tracheoscopically during 4 weeks and were submitted to euthanasia. Macroscopic and microscopic examinations of the tracheal anastomotic healing were evaluated. Biochemical collagen quantification by the Woessner method was performed to evaluate the collagen development at the anastomotic site. All the animals survived the surgical procedure and the study time. No animal presented differences in clinical evaluation. Radiological and endoscopical findings both two showed more development of the tracheal stenosis in-group than in group II. The tracheoscopy and macroscopic studies showed major inflammation and development of fibrotic tissue with a firm consistency in the healing of the group I than in group II. Microscopic examination in group I showed severe fibrosis and inflammatory reaction. The group II presented deposits of a thin and organized collagen fibers and minimal inflammatory reaction. Biochemical collagen concentration was larger in-group I, however significantly. We conclude that the hyaluronic acid applied after cervical tracheoplasty in dogs reduces postsurgical tracheal stenosis and inflammation, as well as improve the quality of the tracheal healing.

Adjuvants, Immunologic↗
PubMed2006

Effects of hyaluronic acid on Ca(2+) influx, lactate dehydrogenase activity, and cyclic AMP synthesis in canine ejaculated sperm during In Vitro capacitation.

The effects of hyaluronic acid, which comprises the cumulus intercellular matrix, on Ca(2+) influx, lactate dehydrogenase (LDH) activity, and cyclic AMP synthesis in canine sperm during capacitation was investigated. Ejaculated sperm were collected from 10 Beagle dogs and the sperm were incubated for 4 hr in Eagle's MEM containing 10 microg/ml of hyaluronic acid. The percentages of actively motile sperm, hyperactivated sperm (HA-sperm), acrosome-reacted sperm (AR-sperm), and sperm labeled with fluoresceinated Ca(2+) indicator (Ca(2+)-labeled sperm) were evaluated to assess Ca(2+) influx into the sperm. LDH activity and cAMP concentration were measured in homogenized sperm. The mean percentages of motile sperm, HA-sperm, and Ca(2+)-labeled sperm in the MEM containing hyaluronic acid were higher than in the control medium (P<0.05, 0.05, and 0.01, respectively), but there was no difference between the percentages of AR-sperm. Mean LDH activity and mean cAMP concentration were also significantly higher than the control values (P<0.05). The percentages of HA-sperm correlated with those of Ca(2+)-labeled sperm (r(2)=0.810). The results indicate that hyaluronic acid increases Ca(2+) influx, LDH activity, and cAMP synthesis in canine ejaculated sperm during capacitation in vitro.

Acrosome Reaction↗
PubMed2005

Intra-articular hyaluronic acid for the treatment of osteoarthritis of the knee: systematic review and meta-analysis.

BACKGROUND: Osteoarthritis of the knee affects up to 10% of the elderly population. The condition is frequently treated by intra-articular injection of hyaluronic acid. We performed a systematic review and meta-analysis of randomized controlled trials to assess the effectiveness of this treatment. METHODS: We searched MEDLINE, EMBASE, CINAHL, BIOSIS and the Cochrane Controlled Trial Register from inception until April 2004 using a combination of search terms for knee osteoarthritis and hyaluronic acid and a filter for randomized controlled trials. We extracted data on pain at rest, pain during or immediately after movement, joint function and adverse events. RESULTS: Twenty-two trials that reported usable quantitative information on any of the predefined end points were identified and included in the systematic review. Even though pain at rest may be improved by hyaluronic acid, the data available from these studies did not allow an appropriate assessment of this end point. Patients who received the intervention experienced a reduction in pain during movement: the mean difference on a 100-mm visual analogue scale was -3.8 mm (95% confidence interval [CI] -9.1 to 1.4 mm) after 2-6 weeks, -4.3 mm (95% CI -7.6 to -0.9 mm) after 10-14 weeks and -7.1 mm (95% CI -11.8 to -2.4 mm) after 22-30 weeks. However, this effect was not compatible with a clinically meaningful difference (expected to be about 15 mm on the visual analogue scale). Furthermore, the effect was exaggerated by trials not reporting an intention-to-treat analysis. No improvement in knee function was observed at any time point. Even so, the effect of hyaluronic acid on knee function was more favourable when allocation was not concealed. Adverse events occurred slightly more often among patients who received the intervention (relative risk 1.08, 95% CI 1.01 to 1.15). Only 4 trials explicitly reported allocation concealment, had blinded outcome assessment and presented intention-to-treat data. INTERPRETATION: According to the currently available evidence, intra-articular hyaluronic acid has not been proven clinically effective and may be associated with a greater risk of adverse events. Large trials with clinically relevant and uniform end points are necessary to clarify the benefit-risk ratio.

Humans↗
PubMed2000

Intra-articular hyaluronic acid in the treatment of haemophilic arthropathy of the knee. Clinical, radiological and sonographical assessment.

Hyaluronic acid has been used successfully in the treatment of osteoarthritis since 1989. There is no experience in haemophiliacs in larger study groups. In a prospective study, 20 patients (21 knees) with haemophilic arthropathy of the knee received 20 mg hyaluronic acid by intra-articular injection for 5 consecutive weeks. Assessment included clinical scores, X-ray, magnetic resonance imaging (MRI) and biomechanical motion analysis before and 3 months after the first injection. The score of the WFH advisory committee and the Aichroth score for special evaluation of the knee were used. After an average period of 26 months, the World Federation of Hemophilia (WFH) score, the Aichroth score and the visual analogue scale were evaluated again. All patients had pain caused by their arthropathy, nine of them had positive antibodies to human immunodeficiency virus, and 15 had chronic hepatitis C. The mean WFH score was 8.1 points, the Petterson score was 7.3 points and the Aichroth score was 38 points (maximum 55 points). The WFH score decreased to 7.3 points, the Aichroth score improved to 40 points and the subjective assessment measured with a visual analogue scale improved from 5.3 to 3.7 points. No differences from MRI controls were detected. After 3 months, 14 of 20 patients improved subjectively, particularly in longer walking distance, stair-climbing or initial pain. These positive aspects were limited by arthropathy in adjacent joints. After 26 months 10 patients still are benefiting for up to 31 months follow-up. The average WFH score was 7.3 points, the Aichroth score 39 points, the visual analogue scale 4.0 points. We recommend hyaluronic acid for haemophilic arthropathy of the knee when regular conservative therapy has failed and operative treatment is not feasible.

Activities of Daily Living↗
PubMed1974

Hyaluronic acid in cartilage and proteoglycan aggregation.

1. Dissociation of purified proteoglycan aggregates was shown to release an interacting component of buoyant density higher than that of the glycoprotein-link fraction of Hascall & Sajdera (1969). 2. This component, which produced an increase in hydrodynamic size of proteoglycans on gel chromatography, was isolated by ECTEOLA-cellulose ion-exchange chromatography and identified as hyaluronic acid. 3. The effect of pH of extraction showed that the proportion of proteoglycan aggregates isolated from cartilage was greatest at pH4.5. 4. The proportion of proteoglycans able to interact with hyaluronic acid decreased when extracted above or below pH4.5, whereas the amount of hyaluronic acid extracted appeared constant from pH3.0 to 8.5. 5. Sequential extraction of cartilage with 0.15m-NaCl at neutral pH followed by 4m-guanidinium chloride at pH4.5 was shown to yield predominantly non-aggregated and aggregated proteoglycans respectively. 6. Most of the hyaluronic acid in cartilage, representing about 0.7% of the total uronic acid, was associated with proteoglycan aggregates. 7. The non-aggregated proteoglycans were unable to interact with hyaluronic acid and were of smaller size, lower protein content and lower keratan sulphate content than the disaggregated proteoglycans. Together with differences in amino acid composition this suggested that each type of proteoglycan contained different protein cores.

Acid-Base Equilibrium↗
PubMed2006

Effect of hyaluronic acid on the excursion resistance of tendon graft: a biomechanical in vitro study in a modified human model.

BACKGROUND: Adhesion between the tendon and tendon sheath after flexor tendon graft inhibits restoration of excursion and strength of the grafted tendons, so post-operative finger function is occasionally unsatisfactory. Early setting rehabilitation is one important factor to prevent the adhesion, and another factor may be a lubricant. We considered the possibility of utilizing hyaluronic acid as a lubricant. The goal of this study is to investigate the in vitro effect of hyaluronic acid on tendon excursion resistance against a digital pulley in a modified human model. METHODS: The excursion resistance between grafted intrasynovial and extrasynovial tendons and A2 pulley were evaluated, and compared before and after soaking in 10 mg/ml hyaluronic acid. FINDINGS: The resistance increased after extrasynovial tendon graft, and then it decreased after soaking hyaluronic acid solution. INTERPRETATION: The evidence we collected suggests that some style of administration of the hyaluronic acid might reduce the excursion resistance in the tendon-pulley unit, facilitating post-operative rehabilitation and limiting adhesion, after tendon graft and possibly improve the clinical outcome of flexor tendon graft.

Adjuvants, Immunologic↗
PubMed1989

Developing rat cerebellum--II. Effects of abnormal thyroid states and undernutrition on hyaluronic acid.

The early postnatal pattern of hyaluronic acid (HA) deposition in rat cerebellum is affected by thyroid deficiency, thyroxine treatment and undernutrition. The modification of HA ontogenesis apparently reflects the smaller number of cells formed in undernourished rats, or alterations of cell maturation (accelerated in thyroxine-treated and slowed down in thyroid-deficient rats). The developmentally regulated loss of tissue water is also affected in the three conditions; this can be correlated with the roughly simultaneous disappearance of extracellular, but not of total, HA.

Aging↗
PubMed1978

Hyaluronic acid in the pulmonary secretions of patients with alveolar proteinosis.

Hyaluronic acid was the only glycosaminoglycan found in the pulmonary secretions of patients with alveolar proteinosis. The compound gave a hexouronate/hexosamine molar ratio of about 1:1. Glucosamine constituted over 98% of the hexosamines, the remaining being galactosamine. It moved as a single spot with the mobility of standard hyaluronic acid on cellulose acetate electrophoresis, and this spot disappeared after digestion with hyaluronidase. It was associated with small amounts of proteins, the major amino acids of which are aspartic acid, glutamic acid, glycine, alanine, and leucine.

Amino Acids↗
PubMedDate not supplied

Fabrication of hyaluronic acid hydrogel beads for cell encapsulation.

Hyaluronic acid (HA) hydrogel beads were prepared by photopolymerization of methacrylated HA and N-vinylpyrrolidone using alginate as a temporal spherical mold. Various fabrication conditions for preparing the hydrogel beads, such as the concentration of methacrylated HA and UV irradiation time, were optimized to control swelling properties and enzymatic degradability. A new concept for cell encapsulation is proposed in this paper. Viable cells were directly injected into the hydrogel beads using a microinjection technique. When bovine articular chondrocytes were injected into HA hydrogel beads and cultivated for 1 week, the cells could proliferate well within the HA beads. HA hydrogel beads could be potentially used as injectable cell delivery vehicles for regenerating tissue defects.

Animals↗
PubMed2005

Randomized, double-blind comparison of the efficacy of two hyaluronic acid derivatives, restylane perlane and hylaform, in the treatment of nasolabial folds.

BACKGROUND: Cross-linked hyaluronic acid gels may offer longer-lasting cosmetic correction and a lower risk of immunogenicity than other soft tissue augmentation agents. OBJECTIVE: To compare the efficacy and safety of a non-animal-stabilized hyaluronic acid gel (Restylane Perlane, Q-Med, Uppsala, Sweden) with that of a hylan B gel (Hylaform, Genzyme Corp., Cambridge, MA, USA), a cross-linked hyaluronic acid from chicken combs, for treatment of nasolabial folds. METHODS: One hundred fifty patients with moderate or severe nasolabial folds were randomized to contralateral treatment with Restylane Perlane and Hylaform. Efficacy was assessed using semi-objective outcome instruments at 3, 4.5, and 6 months after achievement of an "optimal cosmetic result". Patients subsequently underwent open-label bilateral retreatment with Restylane Perlane (if required) and were followed up for a further 6 months. RESULTS: The two products were equally effective in producing an optimal cosmetic result, although fewer treatment sessions were required with Restylane Perlane. At 6 months post-treatment, a higher proportion of patients showed a > or = 1-grade improvement in Wrinkle Severity Rating Scale (WSRS) score with Restylane Perlane (75%) than with Hylaform (38%). Restylane Perlane was considered superior in 64% of patients, whereas Hylaform was superior in 8% of patients. Treatment-related adverse events tended to be more frequent with Restylane Perlane. Local injection-site reactions were generally transient and mild or moderate in intensity and were no more frequent after Restylane Perlane retreatment. CONCLUSIONS: Restylane Perlane provides a more durable esthetic improvement than Hylaform and offers acceptable tolerability.

Adult↗