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1.
S Afr Med J ; 111(10): 995-997, 2021 Oct 05.
Article in English | MEDLINE | ID: mdl-34949296

ABSTRACT

BACKGROUND: Reports have emerged globally of antimicrobial resistance (AMR) in Neisseria gonorrhoeae and Mycoplasma genitalium infections. In South Africa (SA), there are substantial differences between private and public healthcare with regard to antimicrobial drug prescribing practice, which could affect AMR patterns of private and public healthcare patients. OBJECTIVES: To perform a pilot study to determine the frequency of AMR of N. gonorrhoeae and M. genitalium in patients accessing SA's private healthcare sector. METHODS: In this cross-sectional study, N. gonorrhoeae-positive cultures and M. genitalium DNA samples were collected from a private healthcare reference laboratory from August 2018 to August 2019. In N. gonorrhoeae-positive cultures, antimicrobial susceptibility testing was performed, followed by N. gonorrhoeae multiantigen sequence typing (NG-MAST) to determine genetic relatedness of the isolates. To determine macrolide and fluoroquinolone resistance rates, M. genitalium-positive samples were analysed by sequencing the 23S rRNA, gyrA and parC genes. RESULTS: Twenty-one N. gonorrhoeae- and 27 M. genitalium-positive specimens were included in this analysis. High rates of resistance were detected among gonococcal isolates, with 90% resistance to tetracycline, 86% to penicillin and 62% to ciprofloxacin, but no resistance to azithromycin, cefixime and ceftriaxone. NG-MAST revealed genetically diverse isolates with 83% novel NG-MAST sequence types. Macrolide and fluoroquinolone resistance-associated mutations were detected in 18.5% (n=5/27) and 7.4% (n=2/27) of M. genitalium strains, respectively. CONCLUSIONS: We observed high frequencies of ciprofloxacin, penicillin and tetracycline resistance in N. gonorrhoeae and macrolide resistance-associated mutations in M. genitalium in private healthcare sector patients in SA. This finding highlights the need to use diagnostics for sexually transmitted infections and to include the private healthcare sector in antimicrobial surveillance and stewardship programmes.


Subject(s)
Anti-Bacterial Agents/therapeutic use , Drug Resistance, Bacterial , Gonorrhea/drug therapy , Mycoplasma Infections/drug therapy , Mycoplasma genitalium/drug effects , Neisseria gonorrhoeae/drug effects , Cross-Sectional Studies , Female , Gonorrhea/epidemiology , Humans , Male , Microbial Sensitivity Tests , Mycoplasma Infections/epidemiology , Mycoplasma genitalium/isolation & purification , Neisseria gonorrhoeae/isolation & purification , Pilot Projects , Private Sector , South Africa
2.
Sci Rep ; 10(1): 18518, 2020 10 28.
Article in English | MEDLINE | ID: mdl-33116233

ABSTRACT

Patient recovery expectations can predict treatment outcome. Little is known about the association of patient recovery expectations on treatment outcome in patients with neck pain consulting a manual therapist. This study evaluates the predictive value of recovery expectations in neck pain patients consulting manual therapists in the Netherlands. The primary outcome measure 'recovery' is defined as 'reduction in pain and perceived improvement'. A prospective cohort study a total of 1195 neck pain patients. Patients completed the Patient Expectancies List (PEL) at baseline (3 item questionnaire, score range from 3 to 12), functional status (NDI), the Global Perceived Effect (GPE) for recovery (7-points Likert scale) post treatment and pain scores (NRS) at baseline and post treatment. The relationship between recovery expectancy and recovery (dichotomized GPE scores) was assessed by logistic regression analysis. Patients generally reported high recovery expectations on all three questions of the PEL (mean sumscores ranging from 11.3 to 11.6). When adjusted for covariates the PEL sum-score did not predict recovery (explained variance was 0.10 for the total PEL). Separately, the first question of the PEL showed predictive potential (OR 3.7; 95%CI 0.19-73.74) for recovery, but failed to reach statistical significance. In this study patient recovery expectations did not predict treatment outcome. Variables predicting recovery were recurrence and duration of pain. The precise relationship between patient recovery expectations and outcome is complex and still inconclusive. Research on patient expectancy would benefit from more consistent use of theoretical expectancy and outcome models.


Subject(s)
Neck Pain/therapy , Recovery of Function/physiology , Adult , Female , Humans , Male , Middle Aged , Motivation , Musculoskeletal Manipulations/methods , Netherlands , Outcome Assessment, Health Care , Pain Measurement , Patient Medication Knowledge/trends , Prognosis , Prospective Studies , Surveys and Questionnaires , Treatment Outcome
3.
Musculoskelet Sci Pract ; 46: 102069, 2020 04.
Article in English | MEDLINE | ID: mdl-31989963

ABSTRACT

The aim of this study is to compare Dutch usual care musculoskeletal therapy in patients with non-specific neck pain with recommendations from international clinical practice guidelines. Physical therapy is diverse, as it may consist of exercise, massage, advice, and other modalities. Physical therapists with post graduate qualifications in manual therapy (MT) may additionally apply spinal thrust manipulation or non-thrust mobilization techniques to treat neck pain. It is important that, in the absence of a Dutch clinical guideline for the treatment of patients with neck pain, musculoskeletal therapists use the available recommendations from international clinical practice guidelines when treating patients with neck pain. One updated clinical practice guideline was identified (Blanpied, 2017), a report from the Task Force on Neck Pain (Guzman et al., 2008) and the IFOMPT International Framework for Examination of the Cervical Region for potential of Cervical Arterial Dysfunction prior to Orthopaedic Manual Therapy Intervention (Rushton et al., 2014). At baseline 1193 patients are included and data with regard to pain, disability, fear avoidance, expectations and applied treatment modalities are gathered. Outcome is measured using the Global Perceived Effect questionnaire. Results show that patients with acute neck pain are treated significantly more often with manipulation compared to patients with sub-acute or chronic neck pain (p < .000) and younger patients are treated with manipulation more often than older patients (p < .000). In the presence of comorbidity, the preference of spinal manipulation seems to diminish, in favour of mobilization and exercise. Almost every patient receives multimodal therapy (94.3%) and spinal manipulation and mobilization are rarely used as a stand-alone treatment (4.5% and 0.8%). Dutch musculoskeletal therapists choose treatment strategies that correspond with recommendations from international guidelines.


Subject(s)
Educational Status , Guideline Adherence , Manipulation, Spinal/standards , Neck Pain/therapy , Physical Therapists/education , Physical Therapists/standards , Adolescent , Adult , Age Factors , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Netherlands , Practice Guidelines as Topic , Prospective Studies
4.
J Ethnopharmacol ; 112(1): 1-6, 2007 May 30.
Article in English | MEDLINE | ID: mdl-17399925

ABSTRACT

The antinociceptive properties of Casearia sylvestris Sw. (Flacourtiaceae) were investigated in various models of pain-related behavior in mice. The hydroalcoholic crude extract of the plant (30-300mg/kg, per os) clearly inhibited nocifensive responses induced by ovalbumin (hindpaw licking) or acetic acid (writhes) in graded fashion. At 300mg/kg, the extract reduced nocifensive behaviors (from 71.1+/-13.3 to 14.8+/-9.3s; from 31.3+/-4.5 to 3.3+/-1.2 writhes, respectively) to similar extents as indomethacin (5mg/kg; 5.7+/-1.1s and 3.3+/-1.2 writhes, respectively). Significant antinociceptive effects in the hot plate test were only detected following administration of the highest extract dose, but this analgesic action appeared to be specific as the extract failed to change motor and exploratory activities. The antinociceptive effect of Casearia sylvestris extract in the acetic acid test was prevented by prior treatment with the non-selective opioid receptor antagonist naloxone (1mg/kg; 5.8+/-4.2 and 31.5+/-3.1 writhes in vehicle-treated and naloxone-treated groups, respectively), indicating that the endogenous opioid system is involved in its analgesic mechanism of action. Thus, our investigation suggests a potential therapeutic benefit of Casearia sylvestris Sw. in treating conditions associated with inflammatory pain.


Subject(s)
Analgesics/pharmacology , Casearia , Pain/drug therapy , Analgesics/therapeutic use , Analgesics/toxicity , Analgesics, Opioid/pharmacology , Animals , Disease Models, Animal , Dose-Response Relationship, Drug , Lethal Dose 50 , Male , Mice , Morphine/pharmacology , Naloxone/pharmacology , Narcotic Antagonists/pharmacology , Pain/etiology , Plant Extracts/pharmacology , Plant Extracts/therapeutic use , Plant Extracts/toxicity , Rats
5.
Can J Microbiol ; 51(8): 643-54, 2005 Aug.
Article in English | MEDLINE | ID: mdl-16234863

ABSTRACT

The culturable component of bacterial communities found in the endoroot and associated exoroot (root zone soil) was examined in potatoes (Solanum tuberosum L.) grown under either conventional or minimum tillage systems. Bacterial species--abundance relationships were determined and in vitro antibiosis ability investigated to discover whether tillage practice or bacteria source (endo- or exoroot) influenced bacterial community structure and functional versatility. Antibiosis abilities against Phytophthora erythroseptica Pethyb. (causal agent of pink rot of potatoes), Streptomyces scabies (Thaxt.) Waksm. and Henrici) (causal agent of potato common scab), and Fusarium oxysporum Schlecht. Emend. Snyder and Hansen (causal agent of fusarium potato wilt) were selected as indicators of functional versatility. Bacterial community species richness and diversity indices were significantly greater (P = 0.001) in the exoroot than in the endoroot. While both endo- and exoroot communities possessed antibiosis ability against the phytopathogens tested, a significantly greater proportion (P = 0.0001) of the endoroot population demonstrated antibiosis ability than its exoroot counterpart against P. erythroseptica and F. oxysporum. Tillage regime had no significant influence on species-abundance relationships in the endo- or exoroot but did influence the relative antibiosis ability of bacteria in in vitro challenges against S. scabies, where bacteria sourced from minimum tillage systems were more likely to have antibiosis ability (P = 0.0151). We postulate that the difference in the frequency of isolates with antibiosis ability among endoroot versus exoroot populations points to the adaptation of endophytic bacterial communities that favour plant host defence against pathogens that attack the host systemically.


Subject(s)
Antibiosis , Bacteria/growth & development , Fusarium/growth & development , Phytophthora/growth & development , Plant Tubers/microbiology , Solanum tuberosum/microbiology , Streptomyces/growth & development , Agriculture/methods , Bacteria/classification , Bacteria/isolation & purification , Ecosystem , Plant Diseases/microbiology
6.
Phys Med Biol ; 45(12): 3563-76, 2000 Dec.
Article in English | MEDLINE | ID: mdl-11131184

ABSTRACT

Clinical application of high-temperature thermal therapy as a treatment for solid tumours requires an accurate and close to real-time method for assessing tissue damage. Imaging methods that detect structural changes during heating may underestimate the extent of thermal damage. This is due to the occurrence of delayed damage manifested at tissue locations exposed to temperatures lower than those required to cause immediate structural changes. An alternative approach is to measure temperature and then calculate the expected damage based on the temperature history at each tissue location. Magnetic resonance (MR) imaging methods now allow temperature maps of the target and surrounding tissues to be generated in almost real-time. The aim of this work was to evaluate whether thermal damage zones calculated on the basis of MR thermometry maps measured during heating correspond to actual tissue damage as measured after treatment by histological methods and MR imaging. Four male rabbits were treated with high-temperature thermal therapy delivered in the brain by a single microwave antenna operating at 915 MHz. MR scanning was performed before, during and after treatment in a 1.5 T whole-body scanner. Temperature maps were produced using the proton resonance frequency (PRF) shift method of MR thermometry. In addition, conventional T1-weighted and T2-weighted spin-echo images were acquired after treatment. Thermal damage zones corresponding to cell death, microvascular blood flow stasis and protein coagulation were calculated using an Arrhenius analysis of the MR temperature/time course data. The calculated zones were compared with the lesions seen on histopathological examination of the brains which were removed within 6-8 h of treatment. The results showed that calculated damage zones based on MR thermometry agreed well with areas of damage as assessed using histology after heating was completed. The data suggest that real-time calculations of final expected thermal damage based on an Arrhenius analysis of MR temperature data may provide a useful method of real-time monitoring of thermal therapy when combined with conventional T2-weighted images taken after treatment.


Subject(s)
Brain/radiation effects , Hot Temperature/therapeutic use , Hyperthermia, Induced/methods , Magnetic Resonance Spectroscopy/methods , Microwaves/therapeutic use , Temperature , Animals , Brain/pathology , Hot Temperature/adverse effects , Magnetic Resonance Imaging/methods , Male , Models, Statistical , Protons , Rabbits , Time Factors
7.
Magn Reson Med ; 43(1): 62-71, 2000 Jan.
Article in English | MEDLINE | ID: mdl-10642732

ABSTRACT

The proton-resonance frequency (PRF) shift method of MR thermometry provides an easy and practical means of quantitatively monitoring in vivo temperatures for MR image-guided thermal-coagulation therapy. However, reported discrepancies in the numerical value of the PRF-thermal coefficient persist, when measured in a variety of experimental conditions and in different tissue types, both ex vivo and in vivo. In this report, a potential source of variation in the PRF-shift method of thermometry is identified that manifests as a constant incremental phase shift per unit change in temperature that is independent of the echo-time setting, when constructing temperature-sensitive phase images from a gradient-echo pulse sequence. It is proposed that this confounding phase-shift offset arises from thermally induced changes in the electrical conductivity of the material. To this end, it is demonstrated that the MR-derived temperature changes could be in error by as much as 28%, as measured from a simple calibration experiment on freshly excised cow liver. A simple method of overcoming this phase-shift offset is described.


Subject(s)
Electromagnetic Fields , Hot Temperature , Hyperthermia, Induced , Liver/physiology , Magnetic Resonance Imaging , Models, Biological , Animals , Artifacts , Cattle , Culture Techniques , Electric Conductivity , Liver/pathology , Phantoms, Imaging , Thermometers
8.
Radiology ; 214(1): 290-7, 2000 Jan.
Article in English | MEDLINE | ID: mdl-10644139

ABSTRACT

Percutaneous interstitial microwave thermoablation of locally recurrent prostate carcinoma was continually guided with magnetic resonance (MR) imaging. Phase images and data were obtained with a rapid gradient-echo technique and were used to derive tissue temperature change on the basis of proton-resonance shift. Thermally devitalized regions correlated well with the phase image findings. MR imaging-derived temperatures were linearly related to the fluoroptic tissue temperatures. MR imaging can be used to guide thermoablation.


Subject(s)
Hyperthermia, Induced/instrumentation , Magnetic Resonance Imaging/instrumentation , Prostatic Neoplasms/therapy , Thermometers , Aged , Artifacts , Humans , Image Processing, Computer-Assisted , Male , Microwaves , Neoplasm Recurrence, Local/pathology , Neoplasm Recurrence, Local/therapy , Neoplasm Staging , Prostate/pathology , Prostatic Neoplasms/pathology , Treatment Outcome
9.
Life Sci ; 64(26): 2429-37, 1999.
Article in English | MEDLINE | ID: mdl-10403502

ABSTRACT

Wilbrandia ebracteata Cogn. (Cucurbitaceae) is commonly known in Brazil as "Taiuia". The roots are employed in folk medicine for the treatment of several diseases, such as rheumatic disease. This study has evaluated the anti-inflammatory action of dicloromethane fraction (F-DCM), purified fraction (PFIII) and Cucurbitacin B extracted from crude extract of W. ebracteata in experimental models in vivo. The F-DCM (0.3 to 10 mg.kg(-1), i.p. or 3 to 30 mg.kg(-1) p.o.) produced significant but not dose-dependent inhibition of the carrageenan-induced cell influx and exsudate leakage in the pleural cavity of mice. The F-DCM 0.01 to 10 mg.kg(-1), i.p. or 0.1 to 10 mg.kg(-1) p.o.) decreased the levels of PGE2 in the exsudate leakage induced by carrageenan in the pleural cavity after 4 h with a calculated ID50 of 0.01 (0.002-0.09, i.p.) and 0.29 (0.05-1.45, p.o.) mg.kg(-1). The PFIII (3 mg.kg(-1), i.p.) inhibited 80% of cell migration (1.50 +/- 0.09 x 10(6) cells/cavity) and exsudate leakage by about 50% (3.09 +/- 0.71 microg/ml) in relation to the control group. Cucurbitacin B (0.1 mg.kg(-1), i.p.), the main compound of PFIII, reduced significantly the levels of PGE2 in the exsudate leakage by 40.7% (10.41 +/- 2.67 ng.ml(-1)). These data show that the active principle(s) present in the F-DCM of W. ebracteata elicited pronounced anti-inflammatory effects when assessed by i.p. or p.o. routes, as well as PFIII. The F-DCM was also able to prevent PGE2 formation in exsudate leakage induced by carrageenan, as well as Cucurbitacin B, its active principle. These results indicate that the anti-inflammatory activity of Wilbrandia ebracteata can be related with the inhibition of the production of PGE2.


Subject(s)
Anti-Inflammatory Agents/therapeutic use , Cucurbitaceae/therapeutic use , Dinoprostone/metabolism , Phytotherapy , Pleurisy/drug therapy , Triterpenes/therapeutic use , Animals , Anti-Inflammatory Agents/administration & dosage , Anti-Inflammatory Agents/chemistry , Anti-Inflammatory Agents/pharmacology , Capillary Permeability/drug effects , Carrageenan/pharmacology , Cucurbitaceae/chemistry , Dexamethasone/pharmacology , Dose-Response Relationship, Drug , Leukocytes, Mononuclear/drug effects , Leukocytes, Mononuclear/immunology , Male , Methylene Chloride , Mice , Neutrophils/drug effects , Neutrophils/immunology , Plant Extracts/administration & dosage , Plant Extracts/chemistry , Plant Extracts/pharmacology , Plant Extracts/therapeutic use , Plants, Medicinal/chemistry , Plants, Medicinal/therapeutic use , Pleural Effusion/drug therapy , Pleurisy/chemically induced , Pleurisy/metabolism , Pleurisy/pathology , Triterpenes/administration & dosage , Triterpenes/chemistry , Triterpenes/pharmacology
10.
Magn Reson Med ; 41(5): 909-18, 1999 May.
Article in English | MEDLINE | ID: mdl-10332873

ABSTRACT

The proton-resonance frequency (PRF) shift method of thermometry has become a promising tool for magnetic resonance image-guided thermal therapies. Although the PRF thermal coefficient has recently been shown to be independent of tissue type when measured ex vivo, significant discrepancy remains on its value for tissues measured in vivo under a variety of experimental conditions. The authors identify a potential source of variation in the PRF thermal coefficient that arises from temperature-induced changes in the volume magnetic susceptibility of tissue and is dependent on the orientation and geometry of the heat-delivery device and its associated heat pattern. This study demonstrates that spatial variations in the apparent PRF thermal coefficient could lead to errors of up to +/-30% in the magnetic resonance estimated temperature change if this effect is ignored.


Subject(s)
Magnetic Resonance Imaging/methods , Thermometers , Algorithms , Body Temperature , Electron Spin Resonance Spectroscopy , Hot Temperature , Humans , Hyperthermia, Induced , Image Processing, Computer-Assisted , Monitoring, Physiologic , Phantoms, Imaging , Protons , Radiology, Interventional , Thermal Conductivity , Thermodynamics
11.
Nurs Sci Q ; 12(1): 52-61, 1999 Jan.
Article in English | MEDLINE | ID: mdl-11847652

ABSTRACT

The purpose of this article is to explore the adequacy of published scientific evidence supporting therapeutic touch as a nursing intervention. Meta-analytic techniques were used to integrate the research-based literature published in the past decade. The results seem to indicate that therapeutic touch has a positive, medium effect on physiological and psychological variables. It is impossible to make any substantive claims at this time because there is limited published research and because many of the studies had significant methodological issues that could seriously bias the reported results. Resolving these methodological issues is imperative for therapeutic touch research to move forward.


Subject(s)
Therapeutic Touch/standards , Bias , Effect Modifier, Epidemiologic , Evidence-Based Medicine , Humans , Nursing Evaluation Research/standards , Research Design/standards , Therapeutic Touch/methods , Therapeutic Touch/nursing , Treatment Outcome
13.
JAMA ; 280(18): 1631, 1998 Nov 11.
Article in English | MEDLINE | ID: mdl-9820272
14.
Heart ; 80(1): 35-9, 1998 Jul.
Article in English | MEDLINE | ID: mdl-9764056

ABSTRACT

OBJECTIVE: To investigate the feasibility of fixed dose, weight adjusted subcutaneous low molecular weight heparin (LMWH), with monitoring of anti-Xa levels and assessment of coronary patency rates after three to five days, thereby giving an initial indication of its safety and efficacy. DESIGN: In 30 patients with acute myocardial infarction, LMWH (nadroparine) was given as a body weight adjusted intravenous bolus with thrombolysis (rt-PA infusion) and in weight adjusted subcutaneous doses at six hours, and every 12 hours thereafter for 72 hours. The target range was defined prospectively as 0.35-0.70 anti-factor Xa activity (aXa) units. The aXa level was measured every six hours. Coronary angiography was performed in all patients within five days after the start of thrombolytic treatment to determine patency (TIMI 2 and 3 flow) of the infarct related artery. RESULTS: The mean (SEM) aXa level over 72 hours was 0.52 (0.08) U/ml; from 12 hours onwards 88% of all aXa measurements were within the target range. At angiography, a patent infarct related artery was present in 24 of the 30 patients. No major bleeding complications occurred, though minor bleeding complications were observed in two patients. CONCLUSIONS: This small study indicates that LMWH is feasible as an adjunct to thrombolysis in patients with acute myocardial infarction. The aXa levels were within the target range and patency rates at three to five days were around 80%, with no major bleeding complications.


Subject(s)
Anticoagulants/therapeutic use , Myocardial Infarction/drug therapy , Nadroparin/therapeutic use , Thrombolytic Therapy , Tissue Plasminogen Activator/therapeutic use , Adult , Aged , Aged, 80 and over , Chemotherapy, Adjuvant , Coronary Angiography , Feasibility Studies , Humans , Middle Aged , Monitoring, Physiologic , Myocardial Infarction/diagnostic imaging , Prospective Studies , Recombinant Proteins/therapeutic use , Treatment Outcome
15.
Magn Reson Med ; 40(3): 454-9, 1998 Sep.
Article in English | MEDLINE | ID: mdl-9727949

ABSTRACT

The temperature sensitivity of the proton-resonance frequency (PRF) has proven valuable for the monitoring of MR image-guided thermal coagulation therapy. However, there is significant inconsistency in reported values of the PRF-thermal coefficient, as measured from experiments encompassing a range of in vivo and ex vivo tissue types and experimental conditions. A method of calibrating the temperature dependence of the PRF is described and results are presented that indicate a tissue-type independence. To this end, other possible mechanisms for variations in the PRF-thermal coefficient are suggested, including physiological perturbations and volume magnetic susceptibility effects from geometry and orientation.


Subject(s)
Hyperthermia, Induced/instrumentation , Magnetic Resonance Imaging/instrumentation , Magnetic Resonance Spectroscopy/instrumentation , Thermometers , Animals , Calibration , Computer Systems , Humans , Phantoms, Imaging , Rabbits , Swine
16.
J Nutr ; 128(9): 1421-8, 1998 Sep.
Article in English | MEDLINE | ID: mdl-9732300

ABSTRACT

Fatty acids in the diet are readily incorporated into lipids in various tissues. However, it is not clear whether all tissues have the same level of incorporation. Second, (n-6) unsaturated fatty acids increase the fluidity of membranes, but this has not been shown for (n-3) fatty acids. In this study, we measured the incorporation of (n-6) and (n-3) fatty acids into erythrocyte membrane lipids and studied their effects on the fluidity of erythrocyte membranes. One group of female miniature swine was made hypercholesterolemic by feeding the swine cholesterol and lard for 2 mo; the other group served as controls and was fed a stock diet. Both groups were then fed either corn oil or menhaden oil or a mixture of the two for 23 additional weeks. Blood was collected at 0, 2, 4, 12 and 23 wk after initialization of the experimental diets, and fatty acid composition of phospholipids was assessed. Membrane phospholipids of pigs fed menhaden oil had elevated (n-3) fatty acids (20:5 and 22:6), and lower 18:2 than those fed corn oil. There was no difference in 20:4 content. The fatty acid changes occurred as early as 2 wk after consumption of the corn oil or menhaden oil in pigs previously fed a stock diet, but it took longer in pigs previously fed lard + cholesterol, indicating residual effects of pretreatment. Menhaden oil increased anisotropy (indicating decreased fluidity) more than corn oil for the nonpolar probe diphenylhexatriene (DPH) at earlier time points, but not at 23 wk. Erythrocyte membrane fluidity was significantly related to membrane polyunsaturate content, with (n-6) fatty acids having a greater influence than (n-3) fatty acids. A comparison of the present red blood cell fatty acid compositions with brain synaptosome fatty acid compositions for the same animals showed poor correlations for some of the fatty acids. There was no significant direct relationship between docosahexaenoate (DHA) concentrations in erythrocyte membranes with DHA concentrations in brain synaptosomes from cerebellum, forebrain and caudate nucleus.


Subject(s)
Corn Oil/administration & dosage , Erythrocyte Membrane/drug effects , Fish Oils/administration & dosage , Hypercholesterolemia/blood , Membrane Fluidity , Membrane Lipids/analysis , Animals , Brain/metabolism , Brain/ultrastructure , Cholesterol/blood , Cholesterol, Dietary , Diet , Diphenylhexatriene , Erythrocyte Membrane/metabolism , Fatty Acids/analysis , Fluorescence Polarization , Hypercholesterolemia/chemically induced , Hypercholesterolemia/physiopathology , Phospholipids/analysis , Swine , Swine, Miniature , Synaptosomes/metabolism
17.
J Magn Reson Imaging ; 8(1): 128-35, 1998.
Article in English | MEDLINE | ID: mdl-9500272

ABSTRACT

The purpose of this experiment was to use MRI to monitor microwave heating and thermal damage of brain tissue in vivo. Interstitial microwave antennas were implanted into the cerebral hemispheres of seven anesthetized rabbits. Variable power of 30 to 100 W was applied for periods of 5 to 15 minutes and tissue temperature was monitored continuously. MR images were obtained throughout the procedure at 20-second intervals, using a spoiled gradient-echo sequence, without significant artifact. Magnitude, phase, and complex difference images all demonstrated temperature-related signal changes during heating. The findings were better visualized on the phase and complex difference images. Phase difference image analysis revealed an approximately linear relationship between phase change and temperature. Post-treatment thermal lesions measured up to 2.0 cm in size on pathologic specimens and exhibited a zonal pattern on spin-echo MR images.


Subject(s)
Brain/pathology , Hyperthermia, Induced/methods , Magnetic Resonance Imaging/methods , Microwaves/therapeutic use , Animals , Diathermy/instrumentation , Male , Rabbits
18.
Radiother Oncol ; 45(1): 95-8, 1997 Oct.
Article in English | MEDLINE | ID: mdl-9364638

ABSTRACT

INTRODUCTION: In attempting to improve local tumor control by higher doses of radiation, there has been a resurgence of interest in the implementation of brachytherapy in the management of primary and recurrent cancers of the nasopharynx. Brachytherapy with its steep dose fall-off is of particular interest because of the proximity of critical dose limiting structures. Recent developments in brachytherapy, such as the introduction of pulsed-dose-rate and high-dose-rate computerized afterloaders, have encouraged further evolution of brachytherapy techniques. MATERIALS AND METHODS: We have designed an inexpensive, re-usable and flexible silicone applicator, tailored to the shape of the soft tissues of the nasopharynx, which can be used with either low-dose-rate brachytherapy or high (pulsed)-dose-rate remote controlled afterloaders. RESULTS AND CONCLUSIONS: This Rotterdam nasopharynx applicator proved to be easy to introduce, patient friendly and can remain in situ for the duration of the treatment (2-6 days). The design, technique of application and the first consecutive 5 years of clinical experience in using this applicator are presented.


Subject(s)
Brachytherapy/instrumentation , Carcinoma, Squamous Cell/radiotherapy , Nasopharyngeal Neoplasms/radiotherapy , Brachytherapy/methods , Dose-Response Relationship, Radiation , Equipment Design , Equipment Safety , Humans , Radiotherapy Dosage , Treatment Outcome
19.
J Pharm Pharmacol ; 49(4): 433-7, 1997 Apr.
Article in English | MEDLINE | ID: mdl-9232544

ABSTRACT

This study has evaluated the possible role played by the L-arginine-nitric oxide pathway in the vasorelaxant action of the hydroalcoholic extract from Eugenia uniflora, and fractions from the extract, in rings of rat thoracic aorta. The addition of an increasing cumulative concentration of hydroalcoholic extract from E. uniflora (1-300 micrograms mL-1) caused a concentration-dependent relaxation response in intact endothelium-thoracic aorta rings pre-contracted with noradrenaline (30-100 nM). The IC50 value, with its respective confidence limit, and the maximum relaxation (Rmax) were 7.02 (4.77-10.00) micrograms mL-1 and 83.94 +/- 3.04%, respectively. The removal of the endothelium completely abolished these responses. The nitric oxide synthase inhibitors N omega-nitro-L-arginine (L-NOARG, 30 microM) and N omega-nitro-L-arginine methyl ester (L-NAME, 30 microM), inhibited the relaxation (Rmax) to -10.43 +/- 7.81% and -3.69 +/- 2.62%, respectively. In addition, L-arginine (1 mM), but not D-arginine (1 mM), completely reversed inhibition by L-NOARG. Methylene blue (30 microM), a soluble guanylate cyclase inhibitor, reduced the relaxation induced by the extract to 14.60 +/- 7.40%. These data indicate that in the rat thoracic aorta the hydroalcoholic extract, and its fractions, from the leaves of E. uniflora have graded and endothelium-dependent vasorelaxant effects.


Subject(s)
Muscle, Smooth, Vascular/drug effects , Nitric Oxide/physiology , Plant Extracts/pharmacology , Alcohols/chemistry , Animals , Aorta, Thoracic , Chemical Fractionation , Cyclic GMP/metabolism , Dose-Response Relationship, Drug , Endothelium, Vascular/physiology , Enzyme Inhibitors/pharmacology , Lethal Dose 50 , Male , Muscle Relaxation/drug effects , Muscle, Smooth, Vascular/physiology , NG-Nitroarginine Methyl Ester/pharmacology , Nitric Oxide Synthase/antagonists & inhibitors , Nitroarginine/pharmacology , Plant Leaves/chemistry , Rats , Rats, Wistar
20.
Med Phys ; 24(2): 269-77, 1997 Feb.
Article in English | MEDLINE | ID: mdl-9048368

ABSTRACT

Changes in magnetic resonance (MR) signals during interstitial microwave heating are reported, and correlated with simultaneously acquired temperature readings from three fiber-optic probes implanted in a polyacrylamide gel phantom. The heating by a MR-compatible microwave antenna did not interfere with simultaneous MR image data acquisition. MR phase-difference images were obtained using a fast two-dimensional-gradient echo sequence. From these images the temperature-sensitive resonant frequency of the 1H nuclei was found to decrease approximately by 0.008 ppm/ degree C. The method and results presented here demonstrate that noninvasive MR-temperature imaging can be performed simultaneously with interstitial microwave thermal treatment.


Subject(s)
Hyperthermia, Induced , Magnetic Resonance Imaging/instrumentation , Microwaves , Temperature , Biophysical Phenomena , Biophysics , Fiber Optic Technology , Microwaves/therapeutic use , Optical Fibers , Phantoms, Imaging
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