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1.
Cureus ; 15(7): e41669, 2023 Jul.
Article in English | MEDLINE | ID: mdl-37575748

ABSTRACT

Periprosthetic joint infection (PJI) is one of the most common complications after total hip arthroplasty (THA). Two-stage revision surgery is one of the treatment options for PJI, however, it has been associated with poor patient tolerance, reduced patient mobility, and periarticular tissue contracture leading to difficulty during second-stage reconstruction. The custom-made articulating spacer (CUMARS) was developed to provide an alternative that is better tolerated and to reduce the complexity of second-stage reconstruction. This study details the treatment of a patient with PJI post-THA with significant periosteal reaction using a CUMARS construct, which enabled immediate post-operative weight bearing, eventual eradication of infection, restoration of femoral bone stock, and avoidance of second-stage reconstruction.

2.
Arthritis Care Res (Hoboken) ; 73(12): 1754-1762, 2021 12.
Article in English | MEDLINE | ID: mdl-32937005

ABSTRACT

OBJECTIVE: To understand what sports orthopedic surgeons (OS), primary care physicians (PCPs) with sports medicine training, and physical therapists (PTs) managing nonelite athletes with anterior cruciate ligament (ACL) injury tell their patients about their osteoarthritis (OA) risk. METHODS: An electronic survey was distributed by the Canadian Academy of Sport and Exercise Medicine (PCPs, OS), the Sports and Orthopedic Divisions of the Canadian Physiotherapy Association (PTs), and to OS identified through the Royal College of Physicians and Surgeons and the Canadian Orthopaedic Association. The survey included 4 sections: demographics, factors discussed, timing of discussions, and discussion of risk factors and their management. Proportions or means with 95% confidence intervals were calculated. RESULTS: A total of 501 health care professionals (HCPs) responded (98 PCPs, 263 PTs, and 140 OS). Of those responding, 70-77% of physicians reported always discussing OA risk, but only 35% of PTs did. All HCPs reported that patient activities perceived as detrimental to knee health, ACL reinjury, and simultaneous injury to other structures in the knee were most often the reason for discussing OA risk. OA risk was discussed at initial management post-injury (65-94%), with few discussing risk subsequently. Eighty percent of physicians and 99% of PTs indicated that PTs were suited to provide OA risk and management information. CONCLUSION: HCPs routinely managing people with ACL injury do not consistently discuss OA risk post-injury with them. Educational strategies for HCPs are urgently needed to develop care pathways inclusive of support for OA risk management following ACL injury.


Subject(s)
Anterior Cruciate Ligament Injuries/complications , Disclosure/statistics & numerical data , Orthopedic Surgeons , Osteoarthritis, Knee/etiology , Physical Therapists , Canada , Cross-Sectional Studies , Humans , Risk Factors , Surveys and Questionnaires
3.
Arthritis Care Res (Hoboken) ; 71(2): 227-236, 2019 02.
Article in English | MEDLINE | ID: mdl-30295430

ABSTRACT

OBJECTIVE: To compare and contrast the perspectives of patients with arthritis and those of rehabilitation professionals regarding starting and sustaining use of physical activity trackers (PATs). METHODS: We conducted focus group sessions with patients, physiotherapists, and occupational therapists in Ontario, Alberta, or British Columbia, Canada. To be eligible, patients must have self-reported a diagnosis of inflammatory or osteoarthritis. Rehabilitation professionals reported that at least 40% of their caseload was dedicated to arthritis care. Participants had any level of experience with PATs. A thematic analytic approach was used. RESULTS: The following 3 themes were identified: 1) anticipating sharing objective measures of physical activity. Participants agreed that use of PATs had the potential to improve consultations between patients with arthritis and rehabilitation professionals but were uncertain how to achieve this potential; 2) perceived or experienced barriers to start or continue using a PAT. Participants shared doubts about whether existing PATs would meet specific needs of patients with arthritis and expressed concerns about possible negative impacts; and 3) bolstering motivation? Although there was agreement that use of PATs could bolster the motivation of patients who were already active, patients and rehabilitation professionals had different opinions regarding whether use of PATs alone would motivate patients to start increasing activity levels. CONCLUSION: Our study highlights similarities and differences between the perspectives of patients and rehabilitation professionals regarding the potential value and risks of integrating PATs into arthritis self-management. Despite agreement about the potential of PATs, participants were uncertain how to effectively incorporate these tools to enhance patient-clinician consultations and had differing views about whether use of PATs would support a patient's motivation to be active.


Subject(s)
Arthritis/rehabilitation , Exercise/physiology , Fitness Trackers/standards , Physical Therapists/standards , Qualitative Research , Self-Management/methods , Adult , Aged , Arthritis/diagnosis , Arthritis/epidemiology , Attitude of Health Personnel , British Columbia/epidemiology , Female , Humans , Male , Middle Aged , Ontario/epidemiology , Young Adult
4.
CMAJ Open ; 6(3): E269-E275, 2018.
Article in English | MEDLINE | ID: mdl-30026190

ABSTRACT

BACKGROUND: It has been suggested that total knee replacement is being performed in people with less-severe osteoarthritis. We aimed to determine whether there were differences in the presurgery profile, symptoms and disability of 2 cohorts who underwent total knee replacement over a 10-year period. METHODS: Patients aged 18-85 years undergoing primary total knee replacement for osteoarthritis at 1 of 4 sites in Toronto and Strathroy, Ontario, were recruited in a cohort study during 2006-2008 (cohort 1) and 2012-2015 (cohort 2). Patients undergoing unicompartmental or revision arthroplasty were excluded. Demographic and health (body mass index [BMI], comorbidity) variables and osteoarthritis severity, as assessed with the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and the disability component of the Late-Life Function and Disability Instrument (LLFDI-D), were collected before surgery. We calculated proportions, means and standard deviations with 95% confidence intervals (CIs) for all data. We constructed density plots by tertile score for the WOMAC pain and physical function subscales and the LLFDI-D limitation scale. RESULTS: There were 494 patients in cohort 1 and 251 patients in cohort 2. There were no differences in age, sex, education, living status, BMI, comorbidity, pain severity or disability between the cohorts based on overlapping 95% CIs and the density plots. More patients in cohort 1 than in cohort 2 were single (176 [35.6%], 95% CI 32.5%-41.1% v. 63 [25.1%], 95% CI 20.3%-31.0%). Patients in cohort 2 reported less limitation in higher-demand activities than did those in cohort 1 (mean score on LLFDI-D 62.3 [95% CI 60.7-63.9] v. 59.2 [95% CI 58.2-60.2]). INTERPRETATION: The patient profile and reported osteoarthritis severity were similar in 2 cohorts that had total knee replacement over a 10-year period. This suggests that increasing total knee replacement volumes over this period likely were not driven by these factors.

5.
BMJ Open ; 7(8): e015737, 2017 Aug 18.
Article in English | MEDLINE | ID: mdl-28821515

ABSTRACT

OBJECTIVE: The impact of the context of a person's life on recovery from surgical interventions is not well understood. This study evaluated if people's social, environmental and biomedical context was associated with change in frequency in engagement in life activities after total knee replacement (TKR). METHODS: 418 people aged 30+ years who had TKR were followed presurgery to 1 year postsurgery. The outcome was change in frequency in engagement in life activities measured by the Late Life Disability Index (LLDI). Predictor variables of interest evaluated in multivariable linear regression analysis were positive and negative life events (Life Experiences Survey), development of a new comorbidity, another joint replacement and complications after TKR surgery. RESULTS: Mean age was 65 years, 36% were male; 22% and 21% had no comorbidity presurgery and postsurgery. Presurgery LLDI frequency was 69.6 (±11.4) and the mean change was 6.1 (±10.2). Thirty-four per cent and 65% reported at least one positive or negative life event. Seven per cent developed hypertension, 6% cardiovascular disease, 2% lung disease and 2% diabetes. Eleven per cent had a complication and 9% another hip or knee replaced. Smaller changes in LLDI frequency were associated with more negative life events (beta=-0.56; 95% CI -0.92 to-0.18) and complications (beta=-4.01; 95% CI -6.63 to -1.38) after adjusting for age, sex, education, body mass index, comorbidities presurgery, number of symptomatic joints and knee-specific pain and function, LLDI limitations and depression. A new comorbidity or another joint replacement was not associated with outcome in unadjusted or adjusted analysis. CONCLUSIONS: Multifaceted life experiences shape the context of peoples' lives impacting their engagement in activities important for healthy living post-TKR.


Subject(s)
Activities of Daily Living , Arthroplasty, Replacement, Knee , Knee Joint/surgery , Life Change Events , Aged , Arthroplasty, Replacement, Hip , Canada , Comorbidity , Depression/etiology , Disability Evaluation , Female , Humans , Knee Joint/pathology , Male , Middle Aged , Osteoarthritis, Knee/surgery , Pain/etiology , Prospective Studies , Regression Analysis , Surveys and Questionnaires
6.
BMC Health Serv Res ; 16(1): 415, 2016 08 19.
Article in English | MEDLINE | ID: mdl-27543108

ABSTRACT

BACKGROUND: Timely access to effective treatments for arthritis is a priority at national, provincial and regional levels in Canada due to population aging coupled with limited health human resources. Models of care for arthritis are being implemented across the country but mainly in local contexts, not from an evidence-informed policy or framework. The purpose of this study is to examine existing models of care for arthritis in Canada at the local level in order to identify commonalities and differences in their implementation that could point to important considerations for health policy and service delivery. METHODS: Semi-structured key informant interviews were conducted with 70 program managers and/or care providers in three Canadian provinces identified through purposive and snowball sampling followed by more detailed examination of 6 models of care (two per province). Interviews were transcribed verbatim and analyzed thematically using a qualitative descriptive approach. RESULTS: Two broad models of care were identified for Total Joint Replacement and Inflammatory Arthritis. Commonalities included lack of complete and appropriate referrals from primary care physicians and lack of health human resources to meet local demands. Strategies included standardized referrals and centralized intake and triage using non-specialist health care professionals. Differences included the nature of the care and follow-up, the role of the specialist, and location of service delivery. CONCLUSIONS: Current models of care are mainly focused on Total Joint Replacement and Inflammatory Arthritis. Given the increasing prevalence of arthritis and that published data report only a small proportion of current service delivery is specialist care; provision of timely, appropriate care requires development, implementation and evaluation of models of care across the continuum of care.


Subject(s)
Arthritis/therapy , Delivery of Health Care/organization & administration , Health Policy , Arthroplasty, Replacement , Canada , Humans , Interviews as Topic , Models, Theoretical , Referral and Consultation , Triage
7.
J Nurs Manag ; 24(8): 1007-1026, 2016 Nov.
Article in English | MEDLINE | ID: mdl-27573220

ABSTRACT

AIM: The aim of this integrative review was to describe the organisational, unregulated nurse, and resident outcomes associated with effective supervisory performance of regulated nurses (registered nurses or registered practical nurses) in long-term care homes. BACKGROUND: While there are data on the influence of regulated nurse staffing levels on resident outcomes, the influence of effective supervisory performance of regulated nurses on resident and organisational outcomes, nursing assistant outcomes have yet to be comprehensively explored. EVALUATION: A search of six databases was made for articles dating from 2000 to 2015. Twenty-four articles were selected and an integrative review was performed. RESULTS: Effective nurse supervision had statistically significant positive associations (P < 0.05, P < 0.000) with six different organisational, unregulated nurse and resident outcomes: nurse assistant job satisfaction, turnover/intention to leave, effectiveness, decision making, job stress and consumer satisfaction. Qualitative analyses corroborate these findings. CONCLUSIONS: There appear to be some associations between effective supervisory performance of regulated nurses with positive organisational, unregulated nursing and resident outcomes. IMPLICATIONS FOR NURSING MANAGEMENT: Nursing managers and leaders in long-term care may promote improvements in effective nurse supervision performance as a way of reducing turnover and improving resident outcomes.


Subject(s)
Leadership , Long-Term Care/standards , Nurse Administrators/standards , Outcome Assessment, Health Care/methods , Work Performance/standards , Attitude of Health Personnel , Humans , Interprofessional Relations , Long-Term Care/methods , Quality of Health Care
8.
Worldviews Evid Based Nurs ; 13(6): 411-419, 2016 Dec.
Article in English | MEDLINE | ID: mdl-27458714

ABSTRACT

BACKGROUND: Understanding the structures and processes related to the supervisor performance of regulated nurses (registered nurses [RN] and registered practical nurses [RPN]) is critical in order to discern how administrators of long-term care (LTC) homes can facilitate and better support nurses given their important contribution to nurse assistants' job satisfaction and resident outcomes. AIMS: The aim of this integrative review is to identify the structures and processes related to supervisory performance of regulated nurses in LTC. METHODS: An electronic search of six databases for studies published in English between 2000 and September 2015 was conducted by a librarian. The inclusion criteria were studies focused on RN or RPN supervisory performance in LTC, which included a structure or process related to supervisory performance of the nurse. Screening, quality assessment using the Mixed Methods Assessment Tool, and data extraction for the included studies were conducted independently by two reviewers. RESULTS: A total of 22 studies were included in the review. Six nurse structures (e.g., nurses' "perceptions of their supervisory role and authority" as well as their "personal qualities"), and eight organizational structures (e.g., "organizational support (culture) for supervisory and management practices" and "staffing levels") were identified. Six processes of effective supervisory performance were identified, such as "being flexible, understanding, considerate listeners and encourage staff input" as well as "respect, value, recognize, acknowledge and motivate" nursing assistants they supervise. LINKING EVIDENCE TO ACTION: The results highlight the nuanced and complex nature of nurses' supervisory performance and the multifaceted approach required to support effective nurse supervisors in LTC. Future research should examine how resident-related structures, as well as other moderators and mediators, may influence supervisory performance. Developing detailed models of effective supervision can inform future interventions targeting modifiable processes related to supervisory performance to thereby change practice and optimize supervisory performance in LTC.


Subject(s)
Attitude of Health Personnel , Leadership , Long-Term Care/standards , Nursing, Supervisory/standards , Process Assessment, Health Care , Humans , Organizational Culture
9.
Phytochemistry ; 71(13): 1545-57, 2010 Sep.
Article in English | MEDLINE | ID: mdl-20615518

ABSTRACT

Root oil of Ligusticum grayi (Apiaceae) contains numerous irregular sesquiterpenoids. In addition to the known acyclic sesquilavandulol and a sesquilavandulyl aldehyde, two thapsanes, one epithapsane, and 14 sesquiterpenoids representing eight hitherto unknown carbon skeletons were found. These skeletons are: prethapsane, i.e. 1,1,2,3a,7,7-hexamethyloctahydro-1H-indene; isothapsane, i.e. 1,2,3a,6,7,7a-hexamethyloctahydro-1H-indene; ligustigrane, i.e. 1,1,2,7,7,7a-hexamethyloctahydro-1H-indene; isoligustigrane, i.e. 1,1,2,6,7,7a-hexamethyloctahydro-1H-indene; preisothapsane, i.e. 1,1,2,3a,6,7-hexamethyloctahydro-1H-indene; isoprethapsane, i.e. 1,1,2,4,7,7-hexamethyloctahydro-1H-indene; allothapsane, i.e. 1,1,2,3a,7,7a-hexamethyloctahydro-1H-indene; and oshalagrane, i.e. 1,1,2,4,6,6-hexamethylspiro[4.4]nonane. The bicyclic sesquiterpenoids are presumably biosynthesized by head-to-head coupling of geranyl diphosphate and dimethylallyl diphosphate, followed by a cyclization sequence leading to a hydroindane skeleton with six one-carbon substituents. Subsequent rearrangements--primarily methyl migrations--account for the remarkable variety of structures represented in L. grayi root oil.


Subject(s)
Ligusticum/chemistry , Plant Roots/chemistry , Sesquiterpenes/chemistry , Magnetic Resonance Spectroscopy , Mass Spectrometry , Plant Oils/chemistry , Sesquiterpenes/isolation & purification
10.
Nat Clin Pract Rheumatol ; 5(1): 46-51, 2009 Jan.
Article in English | MEDLINE | ID: mdl-19098928

ABSTRACT

Symptoms and functional limitations are commonly reported primary outcome measures in ankylosing spondylitis (AS); however, participation has not been widely evaluated, as reflected by the scarcity of literature on the subject. People with AS suggest that participation in social roles (e.g. employment, leisure, and relationships with others) is a critical outcome that is often adversely affected by the sequelae of the disease and by the demands of managing them. Confusion surrounding the concept of 'social role participation' has presented difficulties in defining, developing and using participation as an outcome measure. Specifically, distinguishing participation in a social role from the performance of activities that might be associated with that role is critical for measuring participation, as the repertoire of associated activities will vary between individuals. Furthermore, considering which roles are important to individuals and evaluating their satisfaction with participating in a role at the times and in the ways they would like are also key elements of this measurement. Participation as an outcome measure takes on increased importance in diseases such as AS where, in the absence of a cure, the benefits of interventions often arise from improvements to patients' quality of life. Participation is a predictor of quality of life in diseases other than AS; therefore, evaluating social role participation, understanding the factors that affect it, and intervening to prevent or alleviate participation restrictions will be critical for people with AS.


Subject(s)
Activities of Daily Living , Social Behavior , Spondylitis, Ankylosing/psychology , Disability Evaluation , Humans , Quality of Life , Sickness Impact Profile
11.
J Agric Food Chem ; 56(14): 5595-8, 2008 Jul 23.
Article in English | MEDLINE | ID: mdl-18564847

ABSTRACT

Limonoids are a family of highly oxygenated triterpenoid secondary metabolites found in significant quantities in Citrus and reported to possess multiple health promoting properties. This is the first known report of the isolation and characterization of an epimer of limonin. The epimer, named epilimonin, was isolated by fractional crystallization from a mixture consisting mainly of limonin and epilimonin obtained as byproduct from our efforts to isolate limonin glucoside. Side-by-side comparison of the MS, IR, and (1)H and (13)C NMR data of epilimonin and limonin lead to the assignment of C-17 as the site of epimerization. An earlier study on the bioavailability of limonin glucoside in humans had indicated that limonin glucoside was metabolized to give limonin and a second limonin metabolite. Results from analyzing epilimonin by the same chromatographic conditions used for the bioavailability study suggest that the second limonin metabolite was epilimonin.


Subject(s)
Citrus/chemistry , Limonins/chemistry , Limonins/isolation & purification , Chemical Fractionation , Chromatography, High Pressure Liquid , Crystallization , Isomerism , Limonins/analysis , Magnetic Resonance Spectroscopy , Spectrometry, Mass, Electrospray Ionization
12.
Lipids ; 41(1): 77-83, 2006 Jan.
Article in English | MEDLINE | ID: mdl-16555475

ABSTRACT

The purpose of this investigation was to develop conditions for producing 2-monoricinoleoyl DAG. We used lipase-catalyzed hydrolysis of triricinolein to obtain 2-monoricinolein and thereafter synthesized 1,2(2,3)-diricinolein through esterification of 2-monoricinolein, using ricinoleic acid as the acyl donor. Five different 1,3-specific immobilized lipases were tested for the initial methanolysis reaction: Candida antarctica type B, Rhizomucor miehei, Rhizopus oryzae (ROL), Thermomyces lanuginosus, and Aspergillus niger. For the second esterification reaction, we investigated these five lipases plus Pseudomonas cepacia, Penicillium roquefortii, Candida rugosa, and Pseudomonas fluorescence. Toluene and diisopropyl ether (DIPE) were examined as reaction media at a water activity of 0.11. ROL in DIPE gave the highest yield of 2-monoricinolein from triricinolein, 78% after 3 h of reaction. The isolated 2-monoricinolein was esterified with ricinoleic acid for synthesis of 1,2(2,3)-diricinolein. ROL in DIPE gave the highest yield of 1,2(2,3)-diricinolein, 58% after 1 h of reaction, and NMR analysis showed that the purity was 97.2%. This methodology can be used for synthesizing radiolabeled 1,2(2,3)-diricinolein to study lipid biosynthesis in castor and other oilseeds.


Subject(s)
Diglycerides/chemical synthesis , Lipase/chemistry , Monoglycerides/chemistry , Catalysis , Chromatography, High Pressure Liquid , Esterification , Magnetic Resonance Spectroscopy
13.
J Ethnopharmacol ; 105(1-2): 255-62, 2006 Apr 21.
Article in English | MEDLINE | ID: mdl-16359837

ABSTRACT

The growth-inhibiting activity of Tabebuia impetiginosa Martius ex DC dried inner bark-derived constituents against Helicobacter pylori ATCC 43504 was examined using paper disc diffusion and minimum inhibitory concentration (MIC) bioassays. The activity of the isolated compounds was compared to that of the commercially available anti-Helicobacter pylori agents, amoxicillin, metronidazole, and tetracycline. The biologically active components of Tabebuia impetiginosa dried inner bark (taheebo) were characterized by spectroscopic analysis as 2-(hydroxymethyl)anthraquinone, anthraquinone-2-carboxylic acid, and 2-hydroxy-3-(3-methyl-2-butenyl)-1,4-naphthoquinone (lapachol). With the paper disc diffusion assay 2-(hydroxymethyl)anthraquinone exhibited strong activity against Helicobacter pylori ATCC 43504 at 0.01 mg/disc. Anthraquinone-2-carboxylic acid, lapachol and metronidazole were less effective, exhibiting moderate anti-Helicobacter pylori activity at 0.1 mg/disc. Amoxicillin and tetracycline were the most potent compounds tested, displaying very strong activity at 0.005 mg/disc. 2-(Hydroxymethyl)anthraquinone exhibited moderate activity at this dose. Tetracycline still had strong activity at 0.001 mg/disc while amoxicillin had little activity at this dose. In the MIC bioassay, 2-(hydroxymethyl)anthraquinone (2 microg/mL), anthraquinone-2-carboxylic acid (8 microg/mL), and lapachol (4 microg/mL) were more active than metronidazole (32 microg/mL) but less effective than amoxicillin (0.063 microg/mL) and tetracycline (0.5 microg/mL). The anti-Helicobacter pylori activity of seven 1,4-naphthoquinone derivatives (structurally related to lapachol), 1,4-naphthoquinone, 5,8-dihydroxy-1,4-naphthoquinone (naphthazarin), 2-methyl-1,4-naphthoquinone (menadione), 2-hydroxy-1,4-naphthoquinone (lawsone), 5-hydroxy-2-methyl-1,4-naphthoquinone (plumbagin), 5-hydroxy-1,4-naphthoquinone (juglone), and 2,3-dichloro-1,4-naphthoquinone (dichlone) was also evaluated using the paper disc assay. Menadione and plumbagin were the most potent compounds tested with the later still exhibiting very strong activity at 0.001 mg/disc. Menadione, juglone and tetracycline had strong activity at this low dose while the latter two compounds and amoxicillin had very strong activity at 0.005 mg/disc. Lawsone was unusual in that it had very strong activity at 0.1 and 0.05 mg/disc but weak activity at doses of 0.01 mg/disc and lower. Naphthazalin, lapachol and dichlone had similar activities while metronidazole had the lowest activity of all compounds tested. These results may be an indication of at least one of the pharmacological actions of taheebo. The Tabebuia impetiginosa dried inner bark-derived materials, particularly 2-(hydroxymethyl)anthraquinone, merit further study as potential Helicobacter pylori eradicating agents or lead compounds.


Subject(s)
Anti-Bacterial Agents/pharmacology , Helicobacter pylori/drug effects , Plant Extracts/pharmacology , Tabebuia/chemistry , Magnetic Resonance Spectroscopy , Mass Spectrometry/methods , Microbial Sensitivity Tests , Spectroscopy, Fourier Transform Infrared
14.
J Agric Food Chem ; 53(19): 7630-6, 2005 Sep 21.
Article in English | MEDLINE | ID: mdl-16159196

ABSTRACT

Commercial grapefruit seed extracts (GSE) were extracted with chloroform. The solvent was evaporated, and the resulting solid was subsequently analyzed by high-performance liquid chromatography (HPLC), electrospray ionization mass spectrometry (ESI/MS), tandem mass spectrometry (ESI/MS/MS), and elemental analysis (by proton-induced X-ray emission analysis). Three major constituents were observed by HPLC and were identified as benzyldimethyldodecylammonium chloride, benzyldimethyltetradecylammonium chloride, and benzyldimethylhexadecylammonium chloride. This mixture of homologues is commonly known as benzalkonium chloride, a widely used synthetic antimicrobial ingredient used in cleaning and disinfection agents.


Subject(s)
Benzalkonium Compounds/analysis , Citrus paradisi/chemistry , Seeds/chemistry , Chloroform , Chromatography, High Pressure Liquid , Magnetic Resonance Spectroscopy , Mass Spectrometry , Plant Extracts/chemistry , Spectrometry, Mass, Electrospray Ionization , Spectrometry, X-Ray Emission
15.
Lipids ; 38(11): 1197-206, 2003 Nov.
Article in English | MEDLINE | ID: mdl-14733366

ABSTRACT

The objective of this study was to find the optimal parameters for lipase-catalyzed methanolysis of triricinolein to produce 1,2(2,3)-diricinolein. Four different immobilized lipases were tested, Candida antarctica type B (CALB), Rhizomucor miehei (RML), Pseudomonas cepacia (PCL), and Penicillium roquefortii (PRL). n-Hexane and diisopropyl ether (DIPE) were examined as reaction media at three different water activities (a(w)), 0.11, 0.53, and 0.97. The consumption of triricinolein and the formation of 1,2(2,3)-diricinolein, methyl ricinoleate, and ricinoleic acid were followed for up to 48 h. PRL gave the highest yield of 1,2(2,3)-diricinolein. Moreover, this lipase showed the highest specificity for the studied reaction, i.e., high selectivity for the reaction with triricinolein but low for 1,2(2,3)-diricinolein. Recoveries of 93 and 88% DAG were obtained using PRL in DIPE at a(w) of 0.11 and 0.53, respectively. Further, NMR studies showed that a higher purity of the 1,2(2,3)-isomer vs. the 1,3-isomer was achieved at higher a(w) (88% at a(w) = 0.53), compared to lower a(w) (71% at a(w) = 0.11). The DAG obtained was acylated by the DAG acyltransferase from Arabidopsis thaliana. Therefore, this enzymatic product is a useful enzyme substrate for lipid biosynthesis. Accordingly, the use of PRL in DIPE at a(w) 0.53 is considered optimal for the synthesis of 1,2(2,3)-diricinolein from triricinolein.


Subject(s)
Lipase/metabolism , Lipid Metabolism , Chromatography, High Pressure Liquid , Enzymes, Immobilized/metabolism , Fatty Acids, Nonesterified/metabolism , Glycerol/metabolism , Lipids/chemistry , Mass Spectrometry , Ricinus/metabolism , Time Factors , Triglycerides/metabolism
16.
J Agric Food Chem ; 50(6): 1393-9, 2002 Mar 13.
Article in English | MEDLINE | ID: mdl-11879009

ABSTRACT

The production of acetylenic phenol metabolites in vitro by three strains of the ascomycete Eutypa lata, the causative agent of dying-arm disease in grapevines, has been investigated. Metabolite composition and yields differed significantly between strains and with growth medium but usually reached a maximum after 24-30 days of fungal growth. A general method for the analysis and identification of metabolites by gas chromatography/mass spectrometry of their trimethylsilyl ether derivatives was developed and individual compounds were quantitated by analytical high-performance liquid chromatography (HPLC) and separated by preparative HPLC. The phenolic aldehyde, eutypine (1), reported to be the grape phytotoxin, occurred in only one of the strains examined whereas the primary metabolite was the corresponding alcohol, eutypinol (2), the presumptive detoxification product. A novel metabolite was isolated as a major constituent, together with a minor component, and their structures were established by spectroscopic methods as a methoxyquinol, named eulatinol (4), and a chromene analog (9) of 2, respectively. The evidence suggests that 1 is not solely responsible for phytotoxicity in grapevines but that dying-arm disease may result from a suite of compounds elaborated by the fungus, with the composition dependent on fungal strain and nutritional source.


Subject(s)
Ascomycota/metabolism , Mycotoxins/metabolism , Plant Diseases/microbiology , Vitis/microbiology , Alkynes , Benzaldehydes/analysis , Benzaldehydes/metabolism , Chromatography, High Pressure Liquid/methods , Gas Chromatography-Mass Spectrometry/methods , Hydrogen-Ion Concentration , Phenols/metabolism
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