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Polymers Oct 2021Layered double hydroxides (LDHs) have attracted interest as reinforcing fillers in elastomers due to their ease of synthesis and customisability. A systematic review was... (Review)
Review
Layered double hydroxides (LDHs) have attracted interest as reinforcing fillers in elastomers due to their ease of synthesis and customisability. A systematic review was performed on the effect of LDHs on the mechanical properties of elastomers using the Scopus database. Of the 61 articles relevant to the search criteria, the majority were published on polyurethane (PU) and nitrile butadiene rubber (NBR). Mg-Al LDH was used in most of the studies and Zn-Al LDH was used second most common. LDH can act as a reinforcing filler, typically increasing tensile strength even at low concentrations, so it could be used as an alternative to traditional reinforcing fillers for elastomers. LDH can also be made a functional filler by selecting the right metals and interlayer anions. It was found that Mg-Al LDH and Zn-Al LDH can both participate in crosslinking reactions and can replace MgO and ZnO, respectively. Less Zn ions are required for crosslinking when LDH is used than when ZnO is used, making LDH more environmentally friendly. Organic modification is usually required to improve compatibility with the elastomer matrix, especially in non-polar elastomers. It enables exfoliation of the LDH and intercalation of polymer chains into the LDH interlayer to occur. Organic modifiers can also be used to functionalise the LDH. Stearic acid used in crosslinking systems can be replaced by stearate anions from stearate-modified LDH.
PubMed: 34771273
DOI: 10.3390/polym13213716 -
The Cochrane Database of Systematic... Sep 2021Each year, in high-income countries alone, approximately 100 million people develop scars. Excessive scarring can cause pruritus, pain, contractures, and cosmetic... (Review)
Review
BACKGROUND
Each year, in high-income countries alone, approximately 100 million people develop scars. Excessive scarring can cause pruritus, pain, contractures, and cosmetic disfigurement, and can dramatically affect people's quality of life, both physically and psychologically. Hypertrophic scars are visible and elevated scars that do not spread into surrounding tissues and that often regress spontaneously. Silicone gel sheeting (SGS) is made from medical-grade silicone reinforced with a silicone membrane backing and is one of the most commonly used treatments for hypertrophic scars.
OBJECTIVES
To assess the effects of silicone gel sheeting for the treatment of hypertrophic scars in any care setting.
SEARCH METHODS
In April 2021 we searched the Cochrane Wounds Specialised Register; the Cochrane Central Register of Controlled Trials (CENTRAL); Ovid MEDLINE (including In-Process & Other Non-Indexed Citations); Ovid Embase and EBSCO CINAHL Plus. We also searched clinical trials registries for ongoing and unpublished studies, and scanned reference lists of relevant included studies as well as reviews, meta-analyses and health technology reports to identify additional studies. There were no restrictions with respect to language, date of publication or study setting.
SELECTION CRITERIA
We included randomised controlled trials (RCTs) that enrolled people with any hypertrophic scars and assessed the use of SGS.
DATA COLLECTION AND ANALYSIS
Two review authors independently performed study selection, 'Risk of bias' assessment, data extraction and GRADE assessment of the certainty of evidence. We resolved initial disagreements by discussion, or by consulting a third review author when necessary.
MAIN RESULTS
Thirteen studies met the inclusion criteria. Study sample sizes ranged from 10 to 60 participants. The trials were clinically heterogeneous with differences in duration of follow-up, and scar site. We report 10 comparisons, SGS compared with no SGS treatment and SGS compared with the following treatments: pressure garments; silicone gel; topical onion extract; polyurethane; propylene glycol and hydroxyethyl cellulose sheeting; Kenalog injection; flashlamp-pumped pulsed-dye laser; intense pulsed light and Gecko Nanoplast (a silicone gel bandage). Six trials had a split-site design and three trials had an unclear design (resulting in a mix of paired and clustered data). Included studies reported limited outcome data for the primary review outcomes of severity of scarring measured by health professionals and adverse events (limited data reported by some included studies, but further analyses of these data was not possible) and no data were reported for severity of scarring reported by patients. For secondary outcomes some pain data were reported, but health-related quality of life and cost effectiveness were not reported. Many trials had poorly-reported methodology, meaning the risk of bias was unclear. We rated all evidence as being either of low or very low certainty, often because of imprecision resulting from few participants, low event rates, or both, all in single studies. SGS compared with no SGS Seven studies with 177 participants compared SGS with no SGS for hypertrophic scars. Two studies with 31 participants (32 scars) reported severity of scarring assessed by health professionals, and it is uncertain whether there is a difference in severity of scarring between the two groups (mean difference (MD) -1.83, 95% confidence interval (CI) -3.77 to 0.12; very low-certainty evidence, downgraded once for risk of bias, and twice for serious imprecision). One study with 34 participants suggests SGS may result in a slight reduction in pain level compared with no SGS treatment (MD -1.26, 95% CI -2.26 to -0.26; low-certainty evidence, downgraded once for risk of bias and once for imprecision). SGS compared with pressure garments One study with 54 participants was included in this comparison. The study reported that SGS may reduce pain levels compared with pressure garments (MD -1.90, 95% CI -2.99 to -0.81; low-certainty evidence, downgraded once for risk of bias and once for imprecision). SGS compared with silicone gel One study with 32 participants was included in this comparison. It is unclear if SGS impacts on severity of scarring assessed by health professionals compared with silicone gel (MD 0.40, 95% CI -0.88 to 1.68; very low-certainty evidence, downgraded once for risk of bias, twice for imprecision). SGS compared with topical onion extract One trial (32 participants) was included in this comparison. SGS may slightly reduce severity of scarring compared with topical onion extract (MD -1.30, 95% CI -2.58 to -0.02; low-certainty evidence, downgraded once for risk of bias, and once for imprecision). SGS compared with polyurethane One study with 60 participants was included in this comparison. It is unclear if SGS impacts on the severity of scarring assessed by health professionals compared with polyurethane (MD 0.50, 95% CI -2.96 to 3.96; very low-certainty evidence, downgraded once for risk of bias, and twice for imprecision). SGS compared with self-adhesive propylene glycol and hydroxyethyl cellulose sheeting One study with 38 participants was included in this comparison. It is uncertain if SGS reduces pain compared with self-adhesive propylene glycol and hydroxyethyl cellulose sheeting (MD -0.12, 95% CI -0.18 to -0.06). This is very low-certainty evidence, downgraded once for risk of bias, once for imprecision and once for indirectness. SGS compared with Gecko Nanoplast One study with 60 participants was included in this comparison. It is unclear if SGS impacts on pain compared with Gecko Nanoplast (MD 0.70, 95% CI -0.28 to 1.68; very low-certainty evidence, downgraded once for risk of bias and twice for imprecision. There was a lack of reportable data from the other three comparisons of SGS with Kenalog injection, flashlamp-pumped pulsed-dye laser or intense pulsed light.
AUTHORS' CONCLUSIONS
There is currently limited rigorous RCT evidence available about the clinical effectiveness of SGS in the treatment of hypertrophic scars. None of the included studies provided evidence on severity of scarring validated by participants, health-related quality of life, or cost effectiveness. Reporting was poor, to the extent that we are not confident that most trials are free from risk of bias. The limitations in current RCT evidence suggest that further trials are required to reduce uncertainty around decision-making in the use of SGS to treat hypertrophic scars.
Topics: Bandages; Cicatrix, Hypertrophic; Humans; Silicone Gels; Wound Healing
PubMed: 34564840
DOI: 10.1002/14651858.CD013357.pub2 -
Bioactive Materials Nov 2021Acute or degenerative meniscus tears are the most common knee lesions. Meniscectomy provides symptomatic relief and functional recovery only in the short- to mid-term... (Review)
Review
Acute or degenerative meniscus tears are the most common knee lesions. Meniscectomy provides symptomatic relief and functional recovery only in the short- to mid-term follow-up but significantly increases the risk of osteoarthritis. For this reason, preserving the meniscus is key, although it remains a challenge. Allograft transplants present many disadvantages, so during the last 20 years preclinical and clinical research focused on developing and investigating meniscal scaffolds. The aim of this systematic review was to collect and evaluate all the available evidence on biosynthetic scaffolds for meniscus regeneration both and in clinical studies. Three databases were searched: 46 preclinical studies and 30 clinical ones were found. Sixteen natural, 15 synthetic, and 15 hybrid scaffolds were studied . Among them, only 2 were translated into clinic: the Collagen Meniscus Implant, used in 11 studies, and the polyurethane-based scaffold Actifit®, applied in 19 studies. Although positive outcomes were described in the short- to mid-term, the number of concurrent procedures and the lack of randomized trials are the major limitations of the available clinical literature. Few studies also combined the use of cells or growth factors, but these augmentation strategies have not been applied in the clinical practice yet. Current solutions offer a significant but incomplete clinical improvement, and the regeneration potential is still unsatisfactory. Building upon the overall positive results of these "old" technologies to address partial meniscal loss, further innovation is urgently needed in this field to provide patients better joint sparing treatment options.
PubMed: 33898878
DOI: 10.1016/j.bioactmat.2021.03.033 -
Medicine Mar 2021The aim of this meta-analysis with trial sequential analysis (TSA) was to evaluate the effect of a polyurethane (PU) tracheal tube cuff on the prevention of... (Meta-Analysis)
Meta-Analysis
Comparison of polyurethane tracheal tube cuffs and conventional polyvinyl chloride tube cuff for prevention of ventilator-associated pneumonia: A systematic review with meta-analysis.
BACKGROUND
The aim of this meta-analysis with trial sequential analysis (TSA) was to evaluate the effect of a polyurethane (PU) tracheal tube cuff on the prevention of ventilator-associated pneumonia (VAP).
METHODS
We performed a systematic search using the MEDLINE database through PubMed, Cochrane Central Register of Controlled Trial, SCOPUS, and Web of Science.Randomized controlled trials comparing the incidence of VAP and clinically relevant outcomes between PU cuff tubes and polyvinyl chloride (PVC) cuff tubes in adult patients. Two authors independently extracted study details, patient characteristics, and clinical outcomes such as incidence of VAP, bacterial colonization of tracheal aspirate, duration of mechanical ventilation, ICU stay, and ICU mortality.
RESULTS
From 309 studies identified as potentially eligible, six studies with 1226 patients were included in this meta-analysis. All studies compared the incidence of VAP between PU cuffs and PVC cuffs. Use of a PU cuff was not associated with a reduction in VAP incidence (RR = 0.68; 95% CI, 0.45-1.03) with significant statistical heterogeneity (I2 = 65%). The quality of evidence was "very low." According to the TSA, the actual sample size was only 15.8% of the target sample size, and the cumulative Z score did not cross the trial sequential monitoring boundary for benefit. No positive impact was reported for the other relevant outcomes for PU cuffs.
CONCLUSIONS
The use of a PU cuff for mechanical ventilation did not prevent VAP. Further trials with a low risk of bias need to be performed.
Topics: Equipment Design; Humans; Intensive Care Units; Intubation, Intratracheal; Pneumonia, Ventilator-Associated; Polyurethanes; Polyvinyl Chloride; Respiration, Artificial
PubMed: 33655952
DOI: 10.1097/MD.0000000000024906 -
The Cochrane Database of Systematic... Feb 2021Extracranial carotid artery stenosis is the major cause of stroke, which can lead to disability and mortality. Carotid endarterectomy (CEA) with carotid patch... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Extracranial carotid artery stenosis is the major cause of stroke, which can lead to disability and mortality. Carotid endarterectomy (CEA) with carotid patch angioplasty is the most popular technique for reducing the risk of stroke. Patch material may be made from an autologous vein, bovine pericardium, or synthetic material including polytetrafluoroethylene (PTFE), Dacron, polyurethane, and polyester. This is an update of a review that was first published in 1996 and was last updated in 2010.
OBJECTIVES
To assess the safety and efficacy of different types of patch materials used in carotid patch angioplasty. The primary hypothesis was that a synthetic material was associated with lower risk of patch rupture versus venous patches, but that venous patches were associated with lower risk of perioperative stroke and early or late infection, or both.
SEARCH METHODS
We searched the Cochrane Stroke Group trials register (last searched 25 May 2020); the Cochrane Central Register of Controlled Trials (CENTRAL; 2020, Issue 4), in the Cochrane Library; MEDLINE (1966 to 25 May 2020); Embase (1980 to 25 May 2020); the Index to Scientific and Technical Proceedings (1980 to 2019); the Web of Science Core Collection; ClinicalTrials.gov; and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) portal. We handsearched relevant journals and conference proceedings, checked reference lists, and contacted experts in the field.
SELECTION CRITERIA
Randomised and quasi-randomised trials (RCTs) comparing one type of carotid patch with another for CEA.
DATA COLLECTION AND ANALYSIS
Two review authors independently assessed eligibility, risk of bias, and trial quality; extracted data; and determined the quality of evidence using the GRADE approach. Outcomes, for example, perioperative ipsilateral stroke and long-term ipsilateral stroke (at least one year), were collected and analysed.
MAIN RESULTS
We included 14 trials involving a total of 2278 CEAs with patch closure operations: seven trials compared vein closure with PTFE closure, five compared Dacron grafts with other synthetic materials, and two compared bovine pericardium with other synthetic materials. In most trials, a patient could be randomised twice and could have each carotid artery randomised to different treatment groups. Synthetic patch compared with vein patch angioplasty Vein patch may have little to no difference in effect on perioperative ipsilateral stroke between synthetic versus vein materials, but the evidence is very uncertain (odds ratio (OR) 2.05, 95% confidence interval (CI) 0.66 to 6.38; 5 studies, 797 participants; very low-quality evidence). Vein patch may have little to no difference in effect on long-term ipsilateral stroke between synthetic versus vein materials, but the evidence is very uncertain (OR 1.45, 95% CI 0.69 to 3.07; P = 0.33; 4 studies, 776 participants; very low-quality evidence). Vein patch may increase pseudoaneurysm formation when compared with synthetic patch, but the evidence is very uncertain (OR 0.09, 95% CI 0.02 to 0.49; 4 studies, 776 participants; very low-quality evidence). However, the numbers involved were small. Dacron patch compared with other synthetic patch angioplasty Dacron versus PTFE patch materials PTFE patch may reduce the risk of perioperative ipsilateral stroke (OR 3.35, 95% CI 0.19 to 59.06; 2 studies, 400 participants; very low-quality evidence). PTFE patch may reduce the risk of long-term ipsilateral stroke (OR 1.52, 95% CI 0.25 to 9.27; 1 study, 200 participants; very low-quality evidence). Dacron may result in an increase in perioperative combined stroke and transient ischaemic attack (TIA) (OR 4.41 95% CI 1.20 to 16.14; 1 study, 200 participants; low-quality evidence) when compared with PTFE. Early arterial re-stenosis or occlusion (within 30 days) was also higher for Dacron patches. During follow-up for longer than one year, more 'any strokes' (OR 10.58, 95% CI 1.34 to 83.43; 2 studies, 304 participants; low-quality evidence) and stroke/death (OR 6.06, 95% CI 1.31 to 28.07; 1 study, 200 participants; low-quality evidence) were reported with Dacron patch closure, although numbers of outcome events were small. Dacron patch may increase the risk of re-stenosis when compared with other synthetic materials (especially with PTFE), but the evidence is very uncertain (OR 3.73, 95% CI 0.71 to 19.65; 3 studies, 490 participants; low-quality evidence). Bovine pericardium patch compared with other synthetic patch angioplasty Bovine pericardium versus PTFE patch materials Evidence suggests that bovine pericardium patch results in a reduction in long-term ipsilateral stroke (OR 4.17, 95% CI 0.46 to 38.02; 1 study, 195 participants; low-quality evidence). Bovine pericardial patch may reduce the risk of perioperative fatal stroke, death, and infection compared to synthetic material (OR 5.16, 95% CI 0.24 to 108.83; 2 studies, 290 participants; low-quality evidence for PTFE, and low-quality evidence for Dacron; OR 4.39, 95% CI 0.48 to 39.95; 2 studies, 290 participants; low-quality evidence for PTFE, and low-quality evidence for Dacron; OR 7.30, 95% CI 0.37 to 143.16; 1 study, 195 participants; low-quality evidence, respectively), but the numbers of outcomes were small. The evidence is very uncertain about effects of the patch on infection outcomes.
AUTHORS' CONCLUSIONS
The number of outcome events is too small to allow conclusions, and more trial data are required to establish whether any differences do exist. Nevertheless, there is little to no difference in effect on perioperative and long-term ipsilateral stroke between vein and any synthetic patch material. Some evidence indicates that other synthetic patches (e.g. PTFE) may be superior to Dacron grafts in terms of perioperative stroke and TIA rates, and both early and late arterial re-stenosis and occlusion. Pseudoaneurysm formation may be more common after use of a vein patch than after use of a synthetic patch. Bovine pericardial patch, which is an acellular xenograft material, may reduce the risk of perioperative fatal stroke, death, and infection compared to other synthetic patches. Further large RCTs are required before definitive conclusions can be reached.
Topics: Aneurysm, False; Angioplasty; Bias; Bioprosthesis; Blood Vessel Prosthesis; Carotid Stenosis; Endarterectomy, Carotid; Humans; Polyethylene Terephthalates; Polytetrafluoroethylene; Postoperative Complications; Randomized Controlled Trials as Topic; Saphenous Vein; Stroke
PubMed: 33598915
DOI: 10.1002/14651858.CD000071.pub4 -
Systematic Review of Thumb Carpometacarpal Joint Hemiresection Interposition Arthroplasty Materials.Hand (New York, N.Y.) Sep 2022Osteoarthritis of the first carpometacarpal joint is a common condition. Various management options and surgical procedures have been described to treat symptomatic...
BACKGROUND
Osteoarthritis of the first carpometacarpal joint is a common condition. Various management options and surgical procedures have been described to treat symptomatic cases. Many systematic reviews examine aspects of thumb carpometacarpal joint osteoarthritis treatment, although none solely examines the outcomes of trapezial partial resection and interposition arthroplasty in stage II to III patients in detail, yet this technique is of growing interest as surgeons seek more nuanced, tailored approaches for osteoarthritis of the first carpometacarpal joint.
METHODS
A systematic review of the thumb carpometacarpal joint hemiresection and interposition arthroplasty was performed with pain assessment as a primary outcome measure and patient-reported outcome measures (PROMs) and reoperation rate as secondary outcome measures. A search was performed between 2004 and 2019 using MEDLINE, Embase, and PubMed. Preferred Reporting Items and Systematic Reviews and Meta-Analyses guidelines were used.
RESULTS
Twenty-nine articles met the inclusion criteria and were included in the final review. Pain relief and improved PROMs were described in all the articles using this technique with all the interposition materials. Materials such as polyurethane urea matrix and poly-l/d-lactide scaffold had higher complication rates. Revision rates varied and were highest with the polyurethane urea matrix.
CONCLUSIONS
This review shows that hemiresection interposition arthroplasty is a useful technique and provides symptomatic benefit in patients with Eaton-Littler stage II and III osteoarthritis. Revision surgery rates due to persistent pain and instability were higher with the use of implants. Larger and long-term studies of this technique using autologous or more bioinert materials and implants are required to assess duration of symptomatic benefit.
Topics: Arthroplasty; Carpometacarpal Joints; Humans; Osteoarthritis; Pain; Polyurethanes; Thumb; Urea
PubMed: 33307813
DOI: 10.1177/1558944720974124 -
European Journal of Vascular and... Feb 2021There is discordance between reviews comparing eversion endarterectomy (EvE) with conventional carotid endarterectomy (CEA) mostly because under this term various... (Comparative Study)
Comparative Study Meta-Analysis
OBJECTIVE
There is discordance between reviews comparing eversion endarterectomy (EvE) with conventional carotid endarterectomy (CEA) mostly because under this term various "closure" techniques are included, from direct closure to a wide spectrum of patches with different materials.
DATA SOURCES
MEDLINE (via PubMed) and SCOPUS.
REVIEW METHODS
This was a systematic review of the Medline (via PubMed) and SCOPUS databases for randomised controlled trials (RCTs) comparing different CEA closure techniques. Network meta-analysis (NMA) was performed with a frequentist approach. The primary and the secondary outcome measures were the 30 day combined stroke and death rate and the late restenosis rate, respectively.
RESULTS
Twenty-three RCTs were finally included in the NMA with a total of 4440 patients randomised, representing seven different techniques (primary carotid closure, n = 753; EvE, n = 431; vein patch closure, n = 973; polytetrafluoroethylene [PTFE] patch, n = 948; Dacron patch, n = 828; bovine pericardium patch, n = 249; and polyurethane patch, n = 258). NMA showed that EvE had a decreased 30 day combined stroke and death rate vs. all other methods of arterial closure, with the exception of PTFE and bovine pericardium patching. Additionally, EvE was associated with the lowest restenosis rate vs. all other methods of arterial closure after CEA. EvE was significantly superior to Dacron patches with regard to late restenosis, with the prediction intervals (PIs) lying completely on the beneficial side (risk ratio 0.06; PI 0.01-0.58) and increasing confidence of this comparison. Rare catastrophic complications of vein patch blow out or synthetic patch infection were reported in 0.2% of the total (n = 9/4 400) and no comparisons were made.
CONCLUSION
EvE and patching with bovine pericardium or PTFE is associated with a lower incidence in both short term and late undesired outcomes following CEA and seems to represent the best choice compared with other carotid closure techniques. These results may support the vascular surgeon's choice of technique/patch material.
Topics: Biocompatible Materials; Blood Vessel Prosthesis; Blood Vessel Prosthesis Implantation; Carotid Arteries; Endarterectomy, Carotid; Humans; Outcome Assessment, Health Care; Postoperative Complications; Wound Closure Techniques
PubMed: 33257115
DOI: 10.1016/j.ejvs.2020.10.009 -
Materials (Basel, Switzerland) Jul 2020We conducted a systematic review in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement to ascertain why... (Review)
Review
We conducted a systematic review in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement to ascertain why polyurethanes (PUs) have been used in the manufacture and design of cardiovascular devices. A complete database search was performed with PubMed, Scopus, and Web of Science as the information sources. The search period ranged from 1 January 2005 to 31 December 2019. We recovered 1552 articles in the first stage. After the duplicate selection and extraction procedures, a total of 21 papers were included in the analysis. We concluded that polyurethanes are being applied in medical devices because they have the capability to tolerate contractile forces that originate during the cardiac cycle without undergoing plastic deformation or failure, and the capability to imitate the behaviors of different tissues. Studies have reported that polyurethanes cause severe problems when applied in blood-contacting devices that are implanted for long periods. However, the chemical compositions and surface characteristics of polyurethanes can be modified to improve their mechanical properties, blood compatibility, and endothelial cell adhesion, and to reduce their protein adhesion. These modifications enable the use of polyurethanes in the manufacture and design of cardiovascular devices.
PubMed: 32707852
DOI: 10.3390/ma13153250 -
Journal of Foot and Ankle Research Jun 2020The effect of different orthotic materials on plantar pressures has not been systematically investigated. This study aimed to review and summarise the findings from...
BACKGROUND
The effect of different orthotic materials on plantar pressures has not been systematically investigated. This study aimed to review and summarise the findings from studies that have evaluated the effect of orthotic materials on plantar pressures.
METHODS
We conducted a systematic review of experimental studies that evaluated the effect of foot orthotic materials or shoe insole materials on plantar pressures using in-shoe testing during walking. The following databases were searched: MEDLINE, CINAHL, Embase and SPORTDiscus. Included studies were assessed for methodological quality using a modified Quality Index. Peak pressure, pressure-time integral, maximum force, force-time integral, contact area, and contact time were variables of interest. Data were synthesised descriptively as studies were not sufficiently homogeneous to conduct meta-analysis. Standardised mean differences (Cohen's d) were calculated to provide the size of the effect between materials found in each study.
RESULTS
Five studies were identified as meeting the eligibility criteria. All five studies were laboratory-based and used a repeated measures design. The quality of the studies varied with scores ranging between 20 and 23 on the modified Quality Index (maximum index score 28). The included studies investigated the effects of polyurethane (including PORON®), polyethylene (including Plastazote®), ethyl vinyl acetate (EVA) and carbon graphite on plantar pressures. Polyurethane (including PORON®), polyethylene (including Plastazote®) and EVA were all found to reduce peak pressure.
CONCLUSION
Based on the limited evidence supplied from the five studies included in this review, some orthotic materials can reduce plantar pressures during walking. Polyurethane (including PORON®), polyethylene (including Plastazote®) and EVA reduce peak pressure beneath varying regions of the foot. Future well-designed studies will strengthen this evidence.
Topics: Adult; Aged; Biomechanical Phenomena; Equipment Design; Female; Foot; Foot Orthoses; Humans; Male; Middle Aged; Plantar Plate; Pressure; Walking; Weight-Bearing
PubMed: 32527296
DOI: 10.1186/s13047-020-00401-3 -
Annals of Work Exposures and Health Jul 2020Diisocyanates are a group of chemicals that are widely used in occupational settings. They are known to induce various health effects, including skin- and respiratory...
Diisocyanates are a group of chemicals that are widely used in occupational settings. They are known to induce various health effects, including skin- and respiratory tract sensitization resulting in allergic dermatitis and asthma. Exposure to diisocyanates has been studied in the past decades by using different types of biomonitoring markers and matrices. The aim of this review as part of the HBM4EU project was to assess: (i) which biomarkers and matrices have been used for biomonitoring diisocyanates and what are their strengths and limitations; (ii) what are (current) biomonitoring levels of the major diisocyanates (and metabolites) in workers; and (iii) to characterize potential research gaps. For this purpose we conducted a systematic literature search for the time period 2000-end 2018, thereby focussing on three types of diisocyanates which account for the vast majority of the total isocyanate market volume: hexamethylene diisocyanate (HDI), toluene diisocyanate (TDI), and 4,4'-methylenediphenyl diisocyanate (MDI). A total of 28 publications were identified which fulfilled the review inclusion criteria. The majority of these studies (93%) investigated the corresponding diamines in either urine or plasma, but adducts have also been investigated by several research groups. Studies on HDI were mostly in the motor vehicle repair industry [with urinary hexamethylene diamine result ranging from 0.03 to 146.5 µmol mol-1 creatinine]. For TDI, there is mostly data on foam production [results for urinary toluene diamine ranging from ~0.01 to 97 µmol mol-1 creatinine] whereas the available MDI data are mainly from the polyurethane industry (results for methylenediphenyl diamine range from 0.01 to 32.7 µmol mol-1 creatinine). About half of the studies published were prior to 2010 hence might not reflect current workplace exposure. There is large variability within and between studies and across sectors which could be potentially explained by several factors including worker or workplace variability, short half-lives of biomarkers, and differences in sampling strategies and analytical techniques. We identified several research gaps which could further be taken into account when studying diisocyanates biomonitoring levels: (i) the development of specific biomarkers is promising (e.g. to study oligomers of HDI which have been largely neglected to date) but needs more research before they can be widely applied, (ii) since analytical methods differ between studies a more uniform approach would make comparisons between studies easier, and (iii) dermal absorption seems a possible exposure route and needs to be further investigated. The use of MDI, TDI, and HDI has been recently proposed to be restricted in the European Union unless specific conditions for workers' training and risk management measures apply. This review has highlighted the need for a harmonized approach to establishing a baseline against which the success of the restriction can be evaluated.
Topics: Biological Monitoring; Humans; Occupational Exposure; Polyurethanes; Toluene 2,4-Diisocyanate; Workplace
PubMed: 32313948
DOI: 10.1093/annweh/wxaa038