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1.
Diabet Med ; 37(1): 29-43, 2020 01.
Article in English | MEDLINE | ID: mdl-31317569

ABSTRACT

AIM: Many women do not attend recommended glucose testing following a pregnancy affected by gestational diabetes (GDM). We aimed to synthesize the literature regarding the views and experiences of women with a history of GDM on postpartum glucose testing, focusing on barriers and facilitators to attendance. METHODS: We systematically identified qualitative studies that examine women's experiences following GDM relating to glucose testing (diabetes screening) or experience of interventions to promote uptake of testing. We conducted a thematic synthesis to develop descriptive and then analytical themes, then developed recommendations to increase uptake based on the findings. We evaluated the quality of each study and the confidence that we had in the recommendations using published checklists. RESULTS: We included 16 articles after screening 23 160 citations and 129 full texts. We identified four themes of influences relating to the healthcare system and personal factors that affected both ability and motivation to attend: relationship with health care, logistics of appointments and tests, family-related practicalities and concern about diabetes. We developed 10 recommendations addressing diabetes risk information and education, and changes to healthcare systems to promote increased attendance at screening in this population, most with high or moderate confidence. CONCLUSIONS: We have identified a need to improve women's understanding about Type 2 diabetes and GDM, and to adjust healthcare provision during and after pregnancy to decrease barriers and increase motivation for testing. Encouraging higher uptake by incorporating these recommendations into practice will enable earlier management of diabetes and improve long-term outcomes.


Subject(s)
Diabetes Mellitus, Type 2/diagnosis , Mass Screening , Adult , Diabetes, Gestational , Female , Glucose Tolerance Test , Humans , Middle Aged , Postpartum Period , Pregnancy , Qualitative Research
2.
Diabet Med ; 36(6): 702-717, 2019 06.
Article in English | MEDLINE | ID: mdl-30723968

ABSTRACT

AIMS: After gestational diabetes, many women exhibit behaviours that increase their risk of developing Type 2 diabetes. We aimed to systematically synthesize the literature that focuses on the views of women with a history of gestational diabetes on reducing their risk of developing diabetes postpartum through lifestyle and behaviour changes. METHODS: We identified qualitative studies that examined the views of women with a history of gestational diabetes towards healthy eating and physical activity, Type 2 diabetes risk management or their experience of a diabetes prevention programme, and conducted a thematic synthesis to develop descriptive and then analytical themes. We also evaluated the quality of each study and the confidence that we had in our findings. RESULTS: We included 21 articles after screening 23 160 citations and 129 full texts. We identified six themes of interacting influences on postpartum behaviour: role as mother and priorities; social support; demands of life; personal preferences and experiences; risk perception and information; and finances and resources (plus preferred format of interventions). These factors inhibited many women from addressing their own health, while they motivated others to persevere. We also developed 20 recommendations, most with high or moderate confidence, for effective promotion of healthy lifestyles in this population. CONCLUSIONS: Many factors hinder healthy lifestyles after gestational diabetes, yet how women interpret them can motivate or prevent changes that reduce diabetes risk. As our recommendations emphasize, women's experiences and needs should be considered when designing strategies to promote healthier lifestyles in this population.


Subject(s)
Diabetes Mellitus, Type 2/prevention & control , Diabetes, Gestational/therapy , Mothers/psychology , Perception , Practice Guidelines as Topic , Puerperal Disorders/prevention & control , Risk Reduction Behavior , Adult , Diabetes Mellitus, Type 2/psychology , Diabetes, Gestational/pathology , Diabetes, Gestational/psychology , Disease Progression , Female , Health Behavior , Healthy Lifestyle/physiology , Humans , Life Style , Mothers/statistics & numerical data , Pregnancy , Puerperal Disorders/psychology
3.
Int J Biol Macromol ; 108: 291-299, 2018 Mar.
Article in English | MEDLINE | ID: mdl-29191425

ABSTRACT

The present study describes the one-step purification and biochemical characterization of an endo-1,4-ß-xylanase from Aspergillus tamarii Kita. Extracellular xylanase was purified to homogeneity 7.43-fold through CM-cellulose. Enzyme molecular weight and pI were estimated to be 19.5kDa and 8.5, respectively. The highest activity of the xylanase was obtained at 60°C and it was active over a broad pH range (4.0-9.0), with maximal activity at pH 5.5. The enzyme was thermostable at 50°C, retaining more than 70% of its initial activity for 480min. The K0.5 and Vmax values on beechwood xylan were 8.13mg/mL and 1,330.20µmol/min/mg of protein, respectively. The ions Ba2+ and Ni2+, and the compounds ß-mercaptoethanol and DTT enhanced xylanase activity, while the heavy metals (Co2+, Cu2+, Hg+, Pb2+ and Zn2+) strongly inhibited the enzyme, at 5mM. Enzymatic hydrolysis of xylooligosaccharides monitored in real-time by mass spectrometer showed that the shortest xylooligosaccharide more efficiently hydrolyzed by A. tamarii Kita xylanase corresponded to xylopentaose. In agreement, HPLC analyzes did not detect xylopentaose among the hydrolysis products of xylan. Therefore, this novel GH11 endo-xylanase displays a series of physicochemical properties favorable to its application in the food, feed, pharmaceutical and paper industries.


Subject(s)
Aspergillus/enzymology , Xylosidases/chemistry , Chromatography , Chromatography, High Pressure Liquid , Enzyme Activation , Enzyme Stability , Glucuronates , Hydrolysis , Kinetics , Mass Spectrometry , Models, Molecular , Molecular Weight , Oligosaccharides , Protein Conformation , Recombinant Proteins , Substrate Specificity , Xylosidases/isolation & purification
4.
Osteoarthritis Cartilage ; 25(1): 76-84, 2017 01.
Article in English | MEDLINE | ID: mdl-27539889

ABSTRACT

OBJECTIVE: To determine the association of different types of meniscal pathology with knee pain, bone marrow lesion (BML) volume, and end-stage knee osteoarthritis (esKOA). DESIGN: Participants were selected from an ancillary project to the Osteoarthritis Initiative (OAI) who had at least one knee with symptomatic osteoarthritis. Baseline magnetic resonance images (MRI) were evaluated for meniscal pathology using a modified International Society of Arthroscopy, Knee Surgery, and Orthopaedic Sports Medicine (ISAKOS) classification system. We collapsed 10 types of meniscal pathology into five categories: normal, intrameniscal signal, morphological deformity/extrusion (altered meniscal shape and/or extrusion but no apparent substance loss), tear, and maceration. Outcomes included Western Ontario and McMaster Universities osteoarthritis index (WOMAC) knee pain and BML volume at baseline and after 2 years. We defined the prevalence of esKOA based on a validated algorithm. We performed logistic regression and adjusted for age, sex, and body mass index (BMI). RESULTS: The 463 participants (53% male) included in the analysis had mean age 63 (9.2) years, BMI 29.6 (4.6) kg/m2, and 71% had Kellgren-Lawrence grade ≥2. Morphological deformity/extrusion and maceration, but no other types of meniscal pathology, were associated with BML volume (morphological deformity/extrusion odds ratio [OR] = 2.47, 95% CI: 1.49, 4.09, maceration OR = 5.85, 95% CI: 3.40, 10.06) and change in BML volume (morphological deformity/extrusion OR = 2.17, 95% CI: 1.37, 3.45, maceration OR = 3.12, 95% CI: 1.87, 5.19). Only maceration was associated with baseline WOMAC knee pain (OR = 2.82, 95% CI: 1.79, 4.43) and prevalence of esKOA (OR = 7.53, 95% CI: 4.25, 13.31). CONCLUSIONS: Based on MRI, morphologic deformity/extrusion and maceration rather than intrameniscal signal or tear were associated with osteoarthritis severity and progression, which highlights the importance of differentiating distinct types of meniscal pathology.


Subject(s)
Meniscus/pathology , Osteoarthritis, Knee/pathology , Arthralgia/diagnostic imaging , Arthralgia/pathology , Female , Humans , Knee Joint/diagnostic imaging , Knee Joint/pathology , Magnetic Resonance Imaging , Male , Meniscus/diagnostic imaging , Middle Aged , Osteoarthritis, Knee/classification , Osteoarthritis, Knee/diagnostic imaging
5.
Protein Eng Des Sel ; 26(1): 15-23, 2013 Jan.
Article in English | MEDLINE | ID: mdl-23012443

ABSTRACT

A bifunctional enzyme has been created by fusing two Bacillus subtilis enzymes: the ß-1,3-1,4-glucanase (BglS, EC 3.2.1.73) that hydrolyzes plant cell wall ß-glucans and the copper-dependent oxidase laccase (CotA, EC 1.10.3.2) that catalyzes the oxidation of aromatic compounds with simultaneous reduction of oxygen to water. The chimeric laccase/ß-1,3-1,4-glucanase was created by insertion fusion of the bglS and cotA genes, and expressed in Escherichia coli. The affinity-purified recombinant chimeric enzyme showed both laccase and glucanase activities, with a maximum laccase activity at pH 4.5 and 75°C that showed a V(max) 30% higher than observed for the parental laccase. The maximum glucanase activity in the chimeric enzyme was at pH 6.0 and 50°C, with a slight reduction in V(max) by ∼10% compared with the parental glucanase. A decreased K(M) resulted in an overall increase in the K(cat)/K(M) value for the glucanase activity of the chimeric enzyme. The hydrolytic activity of the chimera was 20% higher against natural milled sugarcane bagasse as compared with equimolar mixtures of the separate parental enzymes. Molecular dynamics simulations indicated the approximation of the two catalytic domains in the chimeric enzyme, and the formation of an inter-domain interface may underlie the improved catalytic function.


Subject(s)
Bacillus subtilis/enzymology , Cellulose/metabolism , Endo-1,3(4)-beta-Glucanase/metabolism , Laccase/metabolism , Protein Engineering/methods , Saccharum/metabolism , Cellulose/chemistry , Endo-1,3(4)-beta-Glucanase/chemistry , Endo-1,3(4)-beta-Glucanase/genetics , Kinetics , Laccase/chemistry , Laccase/genetics , Molecular Dynamics Simulation , Oxidation-Reduction , Protein Conformation , Recombinant Fusion Proteins/chemistry , Recombinant Fusion Proteins/genetics , Recombinant Fusion Proteins/metabolism , Saccharum/chemistry
6.
Curr Med Chem ; 19(17): 2760-72, 2012.
Article in English | MEDLINE | ID: mdl-22489724

ABSTRACT

It has become apparent in the last years that metal ion homeostasis and its dysfunction which results in increased accumulation in brain, notably of copper, iron and zinc, may be associated with a number of neurodegenerative diseases, such that chelation therapy may be one therapeutic option. We briefly outline chelators currently available together with strategies to develop new chelators capable of crossing the blood-brain-barrier. The homeostasis of iron in brain together with changes in brain iron with ageing are reviewed as well as the role of iron in Parkinson's disease, and the potential of chelation therapy in PD. Copper and zinc homeostasis in brain and age associated changes are then outlined, along with a discussion of the possible involvement of Zn, Cu and Fe in Alzheimer's disease. We conclude with a brief summary of chelation therapy in AD.


Subject(s)
Chelating Agents , Neurodegenerative Diseases , Aging/drug effects , Aging/metabolism , Animals , Chelating Agents/pharmacology , Chelating Agents/therapeutic use , Homeostasis/drug effects , Humans , Metals, Heavy/metabolism , Neurodegenerative Diseases/drug therapy , Neurodegenerative Diseases/metabolism , Neurodegenerative Diseases/physiopathology , Parkinson Disease/drug therapy , Parkinson Disease/metabolism , Parkinson Disease/physiopathology
7.
Parasitol Res ; 107(5): 1163-71, 2010 Oct.
Article in English | MEDLINE | ID: mdl-20680343

ABSTRACT

The proline-rich inhibitor of 31 kDa (PI31) is highly conserved through metazoan evolution, and its activity in the proteasome inhibition is well-established although the precise mechanism of inhibition is unclear. The coding DNA sequence of Schistosoma mansoni PI31 (SmPI31) was cloned, and the recombinant protein was expressed in bacterial system. The correct amino acid sequence was confirmed by mass spectrometry and circular dichroism suggests that SmPI31 contains both α-helix and non-structured regions. Inhibition assays, using the Suc-Leu-Leu-Val-Tyr-4-MCA substrate for proteasome degradation, showed that the S. mansoni proteasome may be regulated by the inhibitory activity of SmPI31. A gene expression assay using qRT-PCR at various stages during the S. mansoni life cycle has shown that SmPI31 transcripts are expressed in all studied stages, suggesting that PI31 plays an important role during the developmental processes of the parasite. In this study first evidence is presented that PI31 has a conserved structure and plays a role as proteasome inhibitor in adult worms and it is expressed through life cycle.


Subject(s)
Cysteine Proteinase Inhibitors/biosynthesis , Gene Expression Profiling , Proteasome Inhibitors , Protozoan Proteins/biosynthesis , Schistosoma mansoni/enzymology , Animals , Circular Dichroism , Cloning, Molecular , Cysteine Proteinase Inhibitors/chemistry , Cysteine Proteinase Inhibitors/genetics , Gene Expression , Mice , Mice, Inbred BALB C , Protein Conformation , Protozoan Proteins/chemistry , Protozoan Proteins/genetics , RNA, Messenger/biosynthesis , RNA, Messenger/genetics , Reverse Transcriptase Polymerase Chain Reaction , Schistosoma mansoni/genetics
8.
Protein Pept Lett ; 16(8): 877-86, 2009.
Article in English | MEDLINE | ID: mdl-19689413

ABSTRACT

Many snake venom phospholipase A(2)s (vPLA(2)s) present biological effects that are independent of hydrolytic activity. Here we review the evidence for the calcium-independent membrane damaging activity of vPLA(2)s, the possible relevance of this activity on their biological effects, and models for the mechanism of membrane permeabilization by these proteins.


Subject(s)
Phospholipases A2/metabolism , Snake Venoms/enzymology , Snakes , Animals , Cell Membrane/metabolism , Cell Membrane Permeability , Humans , Mutagenesis, Site-Directed , Phospholipases A2/chemistry , Phospholipases A2/genetics
9.
Inflamm Res ; 58(4): 210-7, 2009 Apr.
Article in English | MEDLINE | ID: mdl-19169647

ABSTRACT

OBJECTIVE: Suramin is a polysulphonated napthylurea antiprotozoal and anthelminitic drug, which also presents inhibitory activity against a broad range of enzymes. Here we evaluate the effect of suramin on the hydrolytic and biological activities of secreted human group IIA phospholipase A(2) (hsPLA(2)GIIA). MATERIALS AND METHODS: The hsPLA(2)GIIA was expressed in E. coli, and refolded from inclusion bodies. The hydrolytic activity of the recombinant enzyme was measured using mixed dioleoylphosphatidylcholine/dioleoylphosphatidylglycerol (DOPC/DOPG) liposomes. The activation of macrophage cell line RAW 264.7 by hsPLA(2) GIIA was monitored by NO release, and bactericidal activity against Micrococcus luteus was evaluated by colony counting and by flow cytometry using the fluorescent probe Sytox Green. RESULTS: The hydrolytic activity of the hsPLA(2) GIIA was inhibited by a concentration of 100 nM suramin and the activation of macrophages by hsPLA(2) GIIA was abolished at protein/suramin molar ratios where the hydrolytic activity of the enzyme was inhibited. In contrast, both the bactericidal activity of hsPLA(2) GIIA against Micrococcus luteus and permeabilization of the bacterial inner membrane were unaffected by suramin concentrations up to 50 microM. CONCLUSIONS: These results demonstrate that suramin selectively inhibits the activity of the hsPLA(2) GIIA against macrophages, whilst leaving the anti-bacterial function unchanged.


Subject(s)
Antinematodal Agents/pharmacology , Group II Phospholipases A2/metabolism , Macrophage Activation/drug effects , Suramin/pharmacology , Animals , Antinematodal Agents/chemistry , Cell Line , Group II Phospholipases A2/chemistry , Group II Phospholipases A2/genetics , Humans , Inclusion Bodies/enzymology , Macrophage Activation/physiology , Macrophages/cytology , Macrophages/physiology , Microbial Sensitivity Tests , Molecular Structure , Protein Conformation , Recombinant Proteins/chemistry , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Suramin/chemistry
10.
Osteoarthritis Cartilage ; 16(3): 330-6, 2008 Mar.
Article in English | MEDLINE | ID: mdl-18325452

ABSTRACT

RATIONALE: Minimum tibiofemoral joint space width in the medial compartment (JSW) is the most well-established structural outcome measure for osteoarthritis (OA) of the knee. Its usefulness as a measure of therapeutic effectiveness in short-term studies is limited by the rate and variability of joint space narrowing (JSN) in the OA population. Microfocal radiography has been shown to improve reproducibility of JSW measurement compared to standard radiography, but measurement of magnification from microfocal knee films has been problematic, and JSN is yet to be investigated in a longitudinal microfocal study. OBJECTIVE: To establish the effect on JSW reproducibility of a new method of magnification measurement in microfocal radiographs. To report on and compare rates of medial tibiofemoral JSN and their variations in the placebo arms of microfocal and standard radiographic clinical trials in OA, using fluoroscopic semi-flexed (SF) knee positioning. To place in the context of published estimates of rates of JSN from comparable studies. METHODS: Using microfocal radiography, 36 patients were followed at a single centre for 2 years. Using standard radiography, 86 patients were followed for 1 year at a single centre, and 549 for 2 years in a multi-centre international study. Computerised JSW measurement was undertaken using enhanced and automated versions of existing algorithms. Rates of JSN were examined in the context of a review of published rates of JSN using a variety of techniques. RESULTS: Reproducibility of JSW measurement from microfocal radiographs was improved by the new magnification measurement. Rates of JSN were similar across the studies, but more variable when using standard radiography. The rates of JSN were also consistent with those from previously published investigations; all estimates since 2000, bar one, being consistent with the value 0.05 mm/year. CONCLUSION: Microfocal radiography using the new method lowered the variability of the rate of JSN, but the high cost and low availability of microfocal equipment remains a barrier to its more widespread use. The consistently low but highly variable rates of JSN seen in the review suggest that continued attempts to improve radiographic and mensural techniques are unlikely to significantly reduce required sample sizes.


Subject(s)
Knee Joint/diagnostic imaging , Osteoarthritis, Knee/diagnostic imaging , Outcome Assessment, Health Care/statistics & numerical data , Radiographic Magnification/methods , Adult , Aged , Disease Progression , Female , Humans , Knee Joint/pathology , Male , Middle Aged , Osteoarthritis, Knee/pathology , Radiographic Magnification/instrumentation , Reproducibility of Results , Rotation
11.
Biophys Chem ; 125(1): 213-20, 2007 Jan.
Article in English | MEDLINE | ID: mdl-16945473

ABSTRACT

Bothropstoxin-I (BthTx-I) is a Lys49-PLA(2) from the venom of Bothrops jararacussu that lacks detectable catalytic activity, yet causes rapid Ca(2+)-independent membrane damage. With the aim of understanding the interaction between BthTx-I and amphiphilic molecules, we have studied the interaction of sodium dodecyl sulphate (SDS) with the protein. Circular dichroism and attenuated total reflection Fourier-transform infrared spectra of BthTx-I reveal changes in the alpha-helical organization of the protein at an SDS/BthTx-I molar ratio of 20-25. At SDS/BthTx-I ratios of 40-45 the alpha-helices return to a native-like conformation, although fluorescence emission anisotropy measurements of 2-amino-N-hexadecyl-benzamide (AHBA) demonstrate that the total SDS is below the critical micelle concentration when this transition occurs. These results may be interpreted as the result of SDS accumulation by the BthTx-I homodimer and the formation of a pre-micelle SDS/BthTx-I complex, which may subsequently be released from the protein surface as a free micelle. Similar changes in the alpha-helical organization of BthTx-I were observed in the presence of dipalmitoylphosphatidylcholine liposomes, suggesting that protein structure transitions coupled to organization changes of bound amphiphiles may play a role in the Ca(2+)-independent membrane damage by Lys49-PLA(2)s.


Subject(s)
Crotalid Venoms/metabolism , Micelles , Phospholipases A/metabolism , Sodium Dodecyl Sulfate/metabolism , 1,2-Dipalmitoylphosphatidylcholine/pharmacology , Circular Dichroism , Fluorescence Polarization , Hydrogen Bonding/drug effects , Liposomes/pharmacology , Protein Structure, Secondary/drug effects , Sodium Dodecyl Sulfate/pharmacology , Spectroscopy, Fourier Transform Infrared
12.
Rheumatology (Oxford) ; 46(2): 257-64, 2007 Feb.
Article in English | MEDLINE | ID: mdl-16837470

ABSTRACT

OBJECTIVES: To determine whether risedronate (RIS) slows down trabecular bone loss in the medial compartment of the proximal tibia, a characteristic of patients with progressive knee osteoarthritis (OA). METHODS: Initially, 100 patients were randomly selected from each treatment group (each N approximately 300) comprising placebo and RIS 5 mg/day, 15 mg/day and 50 mg/week from a double blind, multi-centre, placebo-controlled, 2 yr investigation of OA knee patients in North America. Using fluoroscopic semi-flexed standard radiography, baseline and exit knee radiographs were digitized by laser scanner. Following computerized measurement of minimum medial compartment joint space width, each group was subdivided into joint space narrowing (JSN) non-progressor or JSN-progressor (JSN >or=0.6 mm measured at any point post-baseline). Computerized method of fractal signature analysis (FSA) quantified longitudinal changes separately in horizontal and vertical trabeculae in region of interest (three-fourth width of tibial compartment x 6 mm height) in the medial compartment. Following the initial study, all JSN-progressor knees within the entire patient cohort (N = 1232) were similarly analysed. RESULTS: OA knees in JSN non-progressor group had a slight decrease in FSA for vertical and horizontal trabeculae and showed no drug effect. In JSN-progressor knees, bone loss was greater in both placebo and RIS 5 mg/day groups compared with those in RIS 15 mg/day group in which trabeculae were retained, and in the RIS 50 mg/week group in which the vertical trabecular number increased significantly (P < 0.05). CONCLUSION: This preliminary study showed that patients with marked cartilage loss (JSN>or=0.6 mm) receiving RIS 15 mg/day retained vertical trabecular structure, and those receiving RIS 50 mg/week increased vertical trabecular number, thereby preserving the structural integrity of subchondral bone in knee OA.


Subject(s)
Bone Density Conservation Agents/therapeutic use , Etidronic Acid/analogs & derivatives , Osteoarthritis, Knee/complications , Osteoporosis/drug therapy , Adult , Aged , Disease Progression , Dose-Response Relationship, Drug , Double-Blind Method , Etidronic Acid/therapeutic use , Female , Humans , Knee Joint/diagnostic imaging , Knee Joint/pathology , Longitudinal Studies , Male , Middle Aged , Osteoarthritis, Knee/diagnostic imaging , Osteoarthritis, Knee/pathology , Osteoporosis/etiology , Radiography , Risedronic Acid , Tibia/physiopathology
13.
Osteoarthritis Cartilage ; 15(2): 179-86, 2007 Feb.
Article in English | MEDLINE | ID: mdl-16905342

ABSTRACT

OBJECTIVE: To determine differences in tibial cancellous bone organisation in knee osteoarthritis (OA) between the central weight-bearing region and juxta-articular radiolucencies adjacent to small, medium or large marginal osteophytes. METHODS: Patients with medial compartment OA (n = 60; F = 39), mean (SD) age 60.0 (9.7) years, and non-OA reference subjects (n = 21; F = 5), mean (SD) age 36.8 (11.5) years, had x4 macroradiographs digitised by laser scanner. Using a modified Osteoarthritis Research Society (OARS) Atlas, right and/or left knees were graded according to marginal osteophyte size into those with small (n = 30), medium (n = 30) or large (n = 27) marginal osteophytes, identified as OPH1, OPH2 and OPH3, respectively. Non-OA knees (n = 30) were anatomically normal. Computerised method of Fractal Signature Analysis (FSA) quantified differences in cancellous bone structure between non-OA and osteophyte subgroups at two regions of interest (ROIs); central weight-bearing and tibial margin. RESULTS: Compared to non-OA, vertical trabecular number increased significantly (P < 0.05) in all osteophyte subgroups (width range 0.12-1.14 mm) within both ROIs. In OPH3, this increase was significantly (P < 0.05) greater compared to OPH2 in the central ROI, and to OPH2 and OPH1 in the marginal ROI at most trabecular widths (0.12-1.14 mm). In the marginal ROI, compared to non-OA, horizontal trabeculae number decreased in all osteophyte subgroups. This decrease was significantly greater in OPH3 compared to OPH2 and OPH1 at small to medium trabecular widths (0.12-0.54 mm). CONCLUSION: Compared to disease associated bone loss at the central ROI of the tibia, the extent of juxta-articular bone loss appears to be associated with the size of the marginal osteophytes.


Subject(s)
Image Processing, Computer-Assisted/methods , Osteoarthritis, Knee/pathology , Radiographic Image Enhancement/methods , Adult , Aged , Female , Humans , Male , Middle Aged , Osteoarthritis, Knee/diagnostic imaging , Tibia/diagnostic imaging
14.
Osteoarthritis Cartilage ; 14(12): 1302-5, 2006 Dec.
Article in English | MEDLINE | ID: mdl-16990028

ABSTRACT

OBJECTIVE: To compare the sensitivity of standard and macro-radiography for quantifying cancellous bone differences between subjects with and without medial compartment knee osteoarthritis (OA). METHODS: Patients with medial compartment knee OA (n=24) and non-OA reference subjects (n=10) had a standard and a macro-radiograph (x4 magnification) of one knee. Fractal Signature Analysis (FSA), a computerised image analysis technique, measured differences in cancellous bone structure between OA and non-OA tibiae in all radiographs. RESULTS: Compared to non-OA, FSA of vertical trabeculae in macro-radiographs increased significantly (P<0.05) in the OA group at several trabecular widths (0.30-0.60mm, 0.7 mm, 0.98-1.14 mm) and in standard radiographs at a single trabecular width (0.48 mm). CONCLUSION: Compared to standard radiography, increased spatial resolution of macro-radiography allowed greater detection of trabecular bone differences between OA and non-OA knees. Nonetheless, difference was also detected in standard radiographs.


Subject(s)
Knee Joint/diagnostic imaging , Osteoarthritis, Knee/diagnostic imaging , Adult , Aged , Aged, 80 and over , Female , Fractals , Humans , Image Processing, Computer-Assisted/methods , Knee Joint/anatomy & histology , Knee Joint/pathology , Male , Middle Aged , Osteoarthritis, Knee/pathology , Radiography , Reproducibility of Results
15.
Osteoarthritis Cartilage ; 13(11): 945-52, 2005 Nov.
Article in English | MEDLINE | ID: mdl-16154773

ABSTRACT

RATIONALE: Superimposition of the rims of the medial tibial plateau to within 1mm is an aim of fluoroscopic knee positioning protocols for osteoarthritic (OA) knee radiography and has also been proposed as a measure of quality for non-fluoroscopic methods. OBJECTIVE: To evaluate the effect of tibial rim alignment (TRA) on reproducibility of joint space width (JSW) measurement, both were measured from radiographs taken with each tibial plateau at a range of angles determined by different non-fluoroscopic views. METHODS: TRA and JSW measurements were taken from both knees of 100 OA patients each radiographed in fully extended, schuss/tunnel, and MTP views. Degree of TRA was compared with JSW reproducibility using correlation, and between groups defined both by the 1mm threshold and by TRA-defined quartiles. RESULTS: JSW reproducibility was dependent on the degree of TRA in the fully extended and schuss/tunnel flexed knee views, although the use of the specific TRA threshold of 1mm was not supported. In the MTP view, JSW measurement was found to be highly reproducible across the full range of TRA values. CONCLUSION: These results contradict claims that TRA to within 1mm is essential for useful measurement of JSW. It is an arbitrary threshold, of use in quality control (QC) for protocols which explicitly require such alignment, and the choice of QC criteria for other protocols should be evaluated on a view-by-view basis. The results confirm previous studies showing the MTP view to afford highly reproducible JSW measurement.


Subject(s)
Knee Joint/diagnostic imaging , Osteoarthritis, Knee/diagnostic imaging , Tibia/diagnostic imaging , Aged , Arthrography/methods , Female , Humans , Male , Middle Aged , Reproducibility of Results
16.
Osteoarthritis Cartilage ; 13(11): 998-1003, 2005 Nov.
Article in English | MEDLINE | ID: mdl-16154774

ABSTRACT

OBJECTIVE: To quantify changes to the trabecular structure in the femoral heads of patients with hip osteoarthritis (OA). METHODS: Patients with OA (n=14; F=7), mean (standard deviation age) 50.6 (10.1) years, had macroradiographs at approximately x4 magnification at baseline and 18 months later using a standardized protocol. Following digitization, computerized measurement was obtained of minimum hip joint space width and fractal signature analysis (FSA) measured longitudinal changes separately in the principal compressive (vertical) and horizontal trabeculae at the region of interest within the centre of the head. RESULTS: The patient group had mean annual rate of joint space narrowing of 0.14+/-0.36 mm/yr. FSA detected no significant changes in horizontal trabeculae, whereas the larger principal compressive (vertical) trabeculae (0.96 mm to 1.02 mm) increased significantly in thickness and the fine to medium trabeculae (0.18 mm to 0.54 mm) decreased significantly in number. CONCLUSION: The increased thickness of the larger trabeculae within the compressive structural element of the femoral head is a response to the increase in stress associated with an overall loss of trabeculae in this region, suggesting the presence of an osteoporosis within the femoral head in OA patients.


Subject(s)
Femur Head/diagnostic imaging , Osteoarthritis, Hip/diagnostic imaging , Female , Fractals , Hip Joint/diagnostic imaging , Humans , Image Interpretation, Computer-Assisted/methods , Longitudinal Studies , Male , Middle Aged , Radiography
17.
Biochimie ; 87(11): 993-1003, 2005 Nov.
Article in English | MEDLINE | ID: mdl-15967564

ABSTRACT

Bothropstoxin-I (BthTx-I) is a homodimeric Lys49-phospholipase A(2) isolated from Bothrops jararacussu venom which damages liposome membranes via a Ca(2+)-independent mechanism. The Glu12/Trp77/Lys80 triad at the dimer interface forms extensive intermolecular hydrogen bonds and hydrophobic contacts, and equilibrium chemical denaturation was used to evaluate the effect on homodimer stability of site-directed mutagenesis of these residues. Changes in the intrinsic fluorescence anisotropy and farUV circular dichroism signals were analyzed using a two-step unfolding model of the BthTx-I dimer to estimate the Gibbs free energy changes of transitions between the dimer and native monomer and between the native and denatured monomers. Whereas the Trp77His, Trp77Gln and Glu12Gln mutants showed native-like dimer stabilities, the Trp77Phe, Lys80Met and Lys80Gly mutants showed significantly reduced K(d) values. A reduced dimer stability is correlated with a decrease in the Ca(2+)-independent membrane damaging activity as monitored by the release of a liposome entrapped fluorescent marker. Although the membrane damaging activity of the monomer is fivefold less than the dimer, the myotoxic activity was unaffected, indicating that these two effects are not correlated. These data suggest that the BthTx-I dimer is predominantly stabilized by hydrogen bonding interactions, and highlight the importance of the homodimeric form for efficient Ca(2+)-independent membrane damage.


Subject(s)
Crotalid Venoms/chemistry , Hydrogen Bonding , Phospholipases A/chemistry , Amino Acid Sequence , Animals , Circular Dichroism , Crotalid Venoms/genetics , Dimerization , Enzyme Stability , Fluorescence Polarization , Liposomes/chemistry , Male , Mice , Mutagenesis, Site-Directed , Protein Denaturation , Protein Structure, Quaternary
18.
Drug Chem Toxicol ; 28(1): 79-90, 2005.
Article in English | MEDLINE | ID: mdl-15720037

ABSTRACT

Rat and human epidermal membranes were mounted onto in vitro diffusion cells with an exposure area of 0.64 cm2, and skin integrity was confirmed using electrical impedance. Following membrane selection, Fluorad FC-118, a 20% aqueous solution of ammonium perfluorooctanoate (AFPO), was applied to the epidermal surface of each skin replicate at approximately 150 microL/cm2 and the donor chamber opening occluded with Parafilm. Serial receptor fluid samples were collected hourly from 1 to 6 h and at 12, 24, 30, and 48 h and analyzed by liquid chromatography-mass spectrometry (LC-MS) for APFO anion (PFO-). For rat skin, the time to steady-state penetration (6500+/-3000 ng APFO x cm(-2) x h(-1)) occurred in less than 12 h, which was sustained until termination (48 h). Based on the concentration of the applied test material, the permeability coefficient (Kp) for APFO in rat skin was calculated to be 3.25+/-1.51 x 10(-5) cm/h. By end of the 48-h exposure period, only a small portion of the total APFO applied (1.44+/-1.13%) had penetrated through rat skin. For human skin, steady-state penetration of APFO (190+/-57 ng APFO x cm(-2) x h(-1)) was reached by 12 h. Based on the concentration of the applied test material, the permeability coefficient for APFO in human skin was calculated to be 9.49+/-2.86 x 10(-7) cm/h. By the end of the 48-h exposure period, only a negligible amount of the total APFO applied (0.048+/-0.01%) had penetrated through human skin. Thus, under infinite dose and occlusive conditions, the steady-state penetration of APFO from a 20% solution was approximately 34-fold faster through rat skin than human skin.


Subject(s)
Caprylates/pharmacokinetics , Epidermis/metabolism , Fluorocarbons/pharmacokinetics , Skin Absorption , Animals , Humans , In Vitro Techniques , Kinetics , Permeability , Rats , Rats, Sprague-Dawley
19.
Article in English | MEDLINE | ID: mdl-16510999

ABSTRACT

Xylanases have been the focus of research owing to their industrial potential in animal feed production, food processing and pulp and paper processes. In order to obtain insight into the structural stability of family 11 xylanases, the mesophilic family 11 xylanase (beta-1,4-xylan xylanohydrolase; EC 3.2.1.8) from Bacillus subtilis 1A1 has been crystallized and diffraction data have been collected to 1.7 A. The crystals belong to the orthorhombic space group P2(1)2(1)2, with unit-cell parameters a = 50.93, b = 70.50, c = 40.05 A. The structure has been determined by molecular replacement, resulting in a crystallographic residual of 36.4% after rigid-body refinement.


Subject(s)
Bacillus subtilis/enzymology , Endo-1,4-beta Xylanases/chemistry , Bacterial Proteins/chemistry , Bacterial Proteins/isolation & purification , Crystallography, X-Ray , Endo-1,4-beta Xylanases/isolation & purification , Protein Conformation , X-Ray Diffraction
20.
Biochem. biophys. res. commun ; 333(4): 1341-1347, 2005.
Article in English | Sec. Est. Saúde SP, SESSP-IBPROD, Sec. Est. Saúde SP, SESSP-IBACERVO | ID: biblio-1060801

ABSTRACT

The HlyX, a putative hemolysin identified from the Leptospira genomes, was cloned, expressed in Escherichia coli, purified, and its hemolytic activity was confirmed. Mouse polyclonal antiserum against the recombinant HlyX recognized HlyX-related antigens in a panel of Leptospira species extracts and it was also able to abolish the hemolytic activity of HlyX. A mixture of HlyX and LipL32, a known hemolysin from Leptospira, induced hemolysis in a synergistic way that was fully inhibited by antiserum against either protein. Moreover, sera from patients with leptospirosis also recognized the recombinant HlyX, showing that it is presented to the host immune system during Leptospira infection.


Subject(s)
Female , Humans , Animals , Mice , Escherichia coli/genetics , Escherichia coli/metabolism , Leptospira interrogans/classification , Leptospira interrogans/metabolism , Escherichia coli Proteins/metabolism , Hemolysis , Hemolysis/physiology , Hemolysin Proteins/pharmacology , Hemolysin Proteins/chemistry , Recombinant Proteins/analysis , Recombinant Proteins/chemistry , Bacterial Proteins/genetics , Bacterial Proteins/metabolism
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