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Treatment of Chinese Patients with Hypertriglyceridemia with a Pharmaceutical-Grade Preparation of Highly Purified Omega-3 Polyunsaturated Fatty Acid Ethyl Esters: Main Results of a Randomized, Double-Blind, Controlled Trial. Vasc Health Risk Manag 2021; 17:571-580. [PMID: 34552329 PMCID: PMC8450163 DOI: 10.2147/vhrm.s325217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 08/26/2021] [Indexed: 11/23/2022] Open
Abstract
Introduction The lipid-modifying potential of omega-3 polyunsaturated fatty acids in Chinese patients is under-researched. We conducted a multicenter, randomized, placebo-controlled, double-blind, parallel-group study of twice-daily treatment with OMACOR (OM3EE), a prescription-only formulation of highly purified ethyl esters of omega-3 polyunsaturated fatty acids in Chinese adult patients (≥18 years) who had elevated baseline fasting serum triglycerides (TG). Methods Patients were stratified according to the severity of their hypertriglyceridemia (severe HTG, with baseline TG ≥500 and <1000 mg/dL or moderate HTG, with baseline TG >200 and <500 mg/dL) or use of statins. Patients randomized to OM3EE therapy received 2 g/day for 4 weeks, then 4 g/day for 8 weeks. The primary efficacy endpoint was the percentage change in fasting serum TG between baseline and the end of treatment in patients with severe HTG. The study was concluded after a planned interim analysis demonstrated a significant TG-lowering effect of OM3EE in that contingent (p=0.0019). Results The mean TG end-of-treatment effect of OM3EE was -29.46% (standard deviation 40.60%) in the severe HTG contingent compared with +0.26% (standard deviation 54.68%) in the placebo group. Corresponding changes were -12.12% and -23.25% in the moderate HTG and combination cohorts (vs +55.45% and +6.24% in relevant placebo groups). A dose-dependent reduction in TG was evident in all patient contingents. Safety and tolerability of OM3EE were in line with previous experience. Discussion These data indicate that OMACOR therapy at a dose of 2-4 g/day is an effective treatment for Chinese patients with raised TG levels and is well tolerated.
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Ultra-low-dose estradiol and dydrogesterone: a phase III study for vasomotor symptoms in China. Climacteric 2021; 25:286-292. [PMID: 34402360 DOI: 10.1080/13697137.2021.1956894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
OBJECTIVE This study aimed to evaluate the efficacy and safety of ultra-low-dose estradiol plus dydrogesterone for vasomotor symptoms in postmenopausal women in China (trial registration CTR20160689). METHODS A total of 332 patients were randomized to continuous combined estradiol 0.5 mg + dydrogesterone 2.5 mg or placebo for 12 weeks. The primary efficacy endpoint was change in the number of hot flushes per day from baseline to end of treatment. Secondary efficacy endpoints included change in the number of moderate-to-severe hot flushes per day, menopausal symptoms from baseline and quality of life. RESULTS Between baseline and end of treatment, change in the mean number of hot flushes per day was -5.9 (95% confidence interval [CI] - 6.6, -5.2) with estradiol + dydrogesterone and -4.5 (95% CI -5.1, -3.8) with placebo, with a mean difference of -1.4 hot flushes per day (95% CI -2.2, -0.7; p < 0.001). Significant differences in favor of estradiol + dydrogesterone were also observed in several secondary efficacy endpoints. The study treatment was well tolerated. CONCLUSION Continuous combined estradiol 0.5 mg + dydrogesterone 2.5 mg reduced hot flushes in postmenopausal women in China. This ultra-low-dose regimen provides an additional option for women experiencing the vasomotor symptoms of menopause. These data are consistent with previous results in other populations.
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Dydrogesterone as an oral alternative to vaginal progesterone for IVF luteal phase support: A systematic review and individual participant data meta-analysis. PLoS One 2020; 15:e0241044. [PMID: 33147288 PMCID: PMC7641447 DOI: 10.1371/journal.pone.0241044] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 10/07/2020] [Indexed: 12/13/2022] Open
Abstract
The aim of this systematic review and meta-analysis was to conduct a comprehensive assessment of the evidence on the efficacy and safety of oral dydrogesterone versus micronized vaginal progesterone (MVP) for luteal phase support. Embase and MEDLINE were searched for studies that evaluated the effect of luteal phase support with daily administration of oral dydrogesterone (20 to 40 mg) versus MVP capsules (600 to 800 mg) or gel (90 mg) on pregnancy or live birth rates in women undergoing fresh-cycle IVF (protocol registered at PROSPERO [CRD42018105949]). Individual participant data (IPD) were extracted for the primary analysis where available and aggregate data were extracted for the secondary analysis. Nine studies were eligible for inclusion; two studies had suitable IPD (full analysis sample: n = 1957). In the meta-analysis of IPD, oral dydrogesterone was associated with a significantly higher chance of ongoing pregnancy at 12 weeks of gestation (odds ratio [OR], 1.32; 95% confidence interval [CI], 1.08 to 1.61; P = 0.0075) and live birth (OR, 1.28; 95% CI, 1.04 to 1.57; P = 0.0214) compared to MVP. A meta-analysis combining IPD and aggregate data for all nine studies also demonstrated a statistically significant difference between oral dydrogesterone and MVP (pregnancy: OR, 1.16; 95% CI, 1.01 to 1.34; P = 0.04; live birth: OR, 1.19; 95% CI, 1.03 to 1.38; P = 0.02). Safety parameters were similar between the two groups. Collectively, this study indicates that a higher pregnancy rate and live birth rate may be obtained in women receiving oral dydrogesterone versus MVP for luteal phase support.
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A Phase III randomized controlled trial of oral dydrogesterone versus intravaginal progesterone gel for luteal phase support in in vitro fertilization (Lotus II): results from the Chinese mainland subpopulation. Gynecol Endocrinol 2020; 36:175-183. [PMID: 31397179 DOI: 10.1080/09513590.2019.1645110] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Lotus II, a randomized, open-label, multicenter, international study compared the efficacy and safety of oral dydrogesterone versus micronized vaginal progesterone (MVP) gel for luteal support in IVF. A prespecified subgroup analysis was performed on 239 Chinese mainland subjects from the overall study population (n = 1034), who were randomized to oral dydrogesterone 30 mg or 8% MVP gel 90 mg daily from the day of oocyte retrieval until 12 weeks of gestation. The aim was to demonstrate non-inferiority of oral dydrogesterone to MVP gel, assessed by the presence of a fetal heartbeat at 12 weeks of gestation. In the Chinese mainland subpopulation, there was a numerical difference of 9.4% in favor of oral dydrogesterone, with ongoing pregnancy rates at 12 weeks of gestation of 61.4% and 51.9% in the oral dydrogesterone and MVP gel groups, respectively (adjusted difference, 9.4%; 95% CI: -3.4 to 22.1); in the overall population, these were 38.7% and 35%, respectively (adjusted difference, 3.7%; 95% CI: -2.3 to 9.7). In both the Chinese mainland subpopulation and the overall population, dydrogesterone had similar efficacy and safety to MVP gel. With convenient oral administration, dydrogesterone has potential to transform luteal support treatment.
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Oral dydrogesterone versus intravaginal micronized progesterone gel for luteal phase support in IVF: a randomized clinical trial. Hum Reprod 2019; 33:2212-2221. [PMID: 30304457 PMCID: PMC6238366 DOI: 10.1093/humrep/dey306] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 09/24/2018] [Indexed: 11/14/2022] Open
Abstract
STUDY QUESTION Is oral dydrogesterone 30 mg daily non-inferior to 8% micronized vaginal progesterone (MVP) gel 90 mg daily for luteal phase support in IVF? SUMMARY ANSWER Oral dydrogesterone demonstrated non-inferiority to MVP gel for the presence of fetal heartbeats at 12 weeks of gestation (non-inferiority margin 10%). WHAT IS KNOWN ALREADY The standard of care for luteal phase support in IVF is the use of MVP; however, it is associated with vaginal irritation, discharge and poor patient compliance. Oral dydrogesterone may replace MVP as the standard of care if it is found to be efficacious with an acceptable safety profile. STUDY DESIGN, SIZE, DURATION Lotus II was a randomized, open-label, multicenter, Phase III, non-inferiority study conducted at 37 IVF centers in 10 countries worldwide, from August 2015 until May 2017. In total, 1034 premenopausal women (>18 to <42 years of age) undergoing IVF were randomized 1:1 (stratified by country and age group), using an Interactive Web Response System, to receive oral dydrogesterone 30 mg or 8% MVP gel 90 mg daily. PARTICIPANTS/MATERIALS, SETTING, METHODS Subjects received either oral dydrogesterone (n = 520) or MVP gel (n = 514) on the day of oocyte retrieval, and luteal phase support continued until 12 weeks of gestation. The primary outcome measure was the presence of fetal heartbeats at 12 weeks of gestation, as determined by transvaginal ultrasound. MAIN RESULTS AND THE ROLE OF CHANCE Non-inferiority of oral dydrogesterone was demonstrated, with pregnancy rates in the full analysis sample (FAS) at 12 weeks of gestation of 38.7% (191/494) and 35.0% (171/489) in the oral dydrogesterone and MVP gel groups, respectively (adjusted difference, 3.7%; 95% CI: −2.3 to 9.7). Live birth rates in the FAS of 34.4% (170/494) and 32.5% (159/489) were obtained for the oral dydrogesterone and MVP gel groups, respectively (adjusted difference 1.9%; 95% CI: −4.0 to 7.8). Oral dydrogesterone was well tolerated and had a similar safety profile to MVP gel. LIMITATIONS, REASONS FOR CAUTION The analysis of the results was powered to consider the ongoing pregnancy rate, but a primary objective of greater clinical interest may have been the live birth rate. This study was open-label as it was not technically feasible to make a placebo applicator for MVP gel, which may have increased the risk of bias for the subjective endpoints reported in this study. While the use of oral dydrogesterone in fresh-cycle IVF was investigated in this study, further research is needed to investigate its efficacy in programmed frozen-thawed cycles where corpora lutea do not exist. WIDER IMPLICATIONS OF THE FINDINGS This study demonstrates that oral dydrogesterone is a viable alternative to MVP gel, due to its comparable efficacy and tolerability profiles. Owing to its patient-friendly oral administration route, dydrogesterone may replace MVP as the standard of care for luteal phase support in fresh-cycle IVF. STUDY FUNDING/COMPETING INTERESTS(S) This study was sponsored and supported by Abbott. G.G. has received investigator fees from Abbott during the conduct of the study. Outside of this submitted work, G.G. has received non-financial support from MSD, Ferring, Merck-Serono, IBSA, Finox, TEVA, Glycotope and Gedeon Richter, as well as personal fees from MSD, Ferring, Merck-Serono, IBSA, Finox, TEVA, Glycotope, VitroLife, NMC Healthcare, ReprodWissen, Biosilu, Gedeon Richter and ZIVA. C.B. is the President of the Belgian Society of Reproductive Medicine (unpaid) and Section Editor of Reproductive BioMedicine Online. C.B. has received grants from Ferring Pharmaceuticals, participated in an MSD sponsored trial, and has received payment from Ferring, MSD, Biomérieux, Abbott and Merck for lectures. G.S. has no conflicts of interest to be declared. A.P. is the General Secretary of the Indian Society of Assisted Reproduction (2017–2018). B.D. is President of Pune Obstetric and Gynecological Society (2017–2018). D.-Z.Y. has no conflicts of interest to be declared. Z.-J.C. has no conflicts of interest to be declared. E.K. is an employee of Abbott Laboratories GmbH, Hannover, Germany and owns shares in Abbott. C.P.-F. is an employee of Abbott GmbH & Co. KG, Wiesbaden, Germany and owns shares in Abbott. H.T.’s institution has received grants from Merck, MSD, Goodlife, Cook, Roche, Origio, Besins, Ferring and Mithra (now Allergan); and H.T. has received consultancy fees from Finox-Gedeon Richter, Merck, Ferring, Abbott and ObsEva. TRIAL REGISTRATION NUMBER NCT02491437 (clinicaltrials.gov). TRIAL REGISTRATION DATE 08 July 2015. DATE OF FIRST PATIENT’S ENROLLMENT 17 August 2015.
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A Phase III randomized controlled trial comparing the efficacy, safety and tolerability of oral dydrogesterone versus micronized vaginal progesterone for luteal support in in vitro fertilization. Hum Reprod 2017; 32:1019-1027. [PMID: 28333318 PMCID: PMC5400051 DOI: 10.1093/humrep/dex023] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 01/25/2017] [Indexed: 12/22/2022] Open
Abstract
STUDY QUESTION Is oral dydrogesterone 30 mg daily (10 mg three times daily [TID]) non-inferior to micronized vaginal progesterone (MVP) 600 mg daily (200 mg TID) for luteal support in in vitro fertilization (IVF), assessed by the presence of fetal heartbeats determined by transvaginal ultrasound at 12 weeks of gestation? SUMMARY ANSWER Non-inferiority of oral dydrogesterone versus MVP was demonstrated at 12 weeks of gestation, with a difference in pregnancy rate and an associated confidence interval (CI) that were both within the non-inferiority margin. WHAT IS KNOWN ALREADY MVP is routinely used in most clinics for luteal support in IVF, but it is associated with side effects, such as vaginal irritation and discharge, as well as poor patient acceptance. Dydrogesterone may be an alternative treatment due to its patient-friendly oral administration. STUDY DESIGN, SIZE, DURATION Lotus I was an international Phase III randomized controlled trial, performed across 38 sites, from August 2013 to March 2016. Subjects were premenopausal women (>18 to <42 years of age; body mass index (BMI) ≥18 to ≤30 kg/m2) with a documented history of infertility who were planning to undergo IVF. A centralized electronic system was used for randomization, and the study investigators, sponsor's study team, and subjects remained blinded throughout the study. PARTICIPANTS/MATERIALS, SETTING, METHODS In total, 1031 subjects were randomized to receive either oral dydrogesterone (n = 520) or MVP (n = 511). Luteal support was started on the day of oocyte retrieval and continued until 12 weeks of gestation (Week 10), if a positive pregnancy test was obtained at 2 weeks after embryo transfer. MAIN RESULTS AND THE ROLE OF CHANCE In the full analysis set (FAS), 497 and 477 subjects in the oral dydrogesterone and MVP groups, respectively, had an embryo transfer. Non-inferiority of oral dydrogesterone was demonstrated, with pregnancy rates at 12 weeks of gestation of 37.6% and 33.1% in the oral dydrogesterone and MVP treatment groups, respectively (difference 4.7%; 95% CI: −1.2–10.6%). Live birth rates of 34.6% (172 mothers with 213 newborns) and 29.8% (142 mothers with 158 newborns) were obtained in the dydrogesterone and MVP groups, respectively (difference 4.9%; 95% CI: −0.8–10.7%). Oral dydrogesterone was well tolerated and had a similar safety profile to MVP. LIMITATIONS, REASONS FOR CAUTION The analysis of the results was powered to consider the clinical pregnancy rate, but the live birth rate may be of greater clinical interest. Conclusions relating to the differences between treatments in live birth rate, observed in this study, should therefore be made with caution. WIDER IMPLICATIONS OF THE FINDINGS Oral dydrogesterone may replace MVP as the standard of care for luteal phase support in IVF, owing to the oral route being more patient-friendly than intravaginal administration, as well as it being a well tolerated and efficacious treatment. STUDY FUNDING/COMPETING INTEREST(S) Sponsored and supported by Abbott Established Pharmaceuticals Division. H.T.’s institution has received grants from Merck, MSD, Goodlife, Cook, Roche, Besins, Ferring and Mithra (now Allergan) and H.T. has received consultancy fees from Finox, Ferring, Abbott, ObsEva and Ovascience. G.S. has nothing to disclose. E.K. is an employee of Abbott GmbH. G.G. has received investigator fees from Abbott during the conduct of the study; outside of this submitted work, G.G. has received personal fees and non-financial support from MSD, Ferring, Merck-Serono, Finox, TEVA, Glycotope, as well as personal fees from VitroLife, NMC Healthcare LLC, ReprodWissen LLC and ZIVA LLC. TRIAL REGISTRATION NUMBER NCT01850030 (clinicaltrials.gov). TRIAL REGISTRATION DATE 19 April 2013. DATE OF FIRST PATIENT'S ENROLLMENT 23 August 2013.
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A Phase III randomized controlled trial comparing the efficacy, safety and tolerability of oral dydrogesterone versus micronized vaginal progesterone for luteal support in in vitro fertilization. Hum Reprod 2017; 32:2152. [PMID: 28938733 DOI: 10.1093/humrep/dex266] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Abstract
1. The metabolism of dydrogesterone was investigated in human liver cytosol (HLC) and human liver microsomes (HLM). Enzymes involved in dydrogesterone metabolism were identified and their relative contributions were estimated. 2. Dydrogesterone clearance was clearly higher in HLC compared to HLM. The major active metabolite 20α-dihydrodydrogesterone (20α-DHD) was only produced in HLC. 3. The formation of 20α-DHD by cytosolic aldo-keto reductase 1C (AKR1C) was confirmed with isoenzyme-specific AKR inhibitors. 4. Using recombinantly expressed human cytochrome P450 (CYP) isoenzymes, dydrogesterone was shown to be metabolically transformed by CYP3A4 and CYP2C19. 5. A clear contribution of CYP3A4 to microsomal metabolism of dydrogesterone was demonstrated with HLM and isoenzyme-specific CYP inhibitors, and confirmed by a significant correlation between dydrogesterone clearance and CYP3A4 activity. 6. Contribution of CYP2C19 was shown to be clearly less than CYP3A4 and restricted to a small group of human individuals with very high CYP2C19 activity. Therefore, it is expected that CYP2C19 genetic variations will not affect dydrogesterone pharmacokinetics in man. 7. In conclusion, dydrogesterone metabolism in the liver is dominated primarily by cytosolic enzymes (particularly AKR1C) and secondarily by CYP3A4, with the former exclusively responsible for 20α-DHD formation.
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Oral ultra-low dose continuous combined hormone replacement therapy with 0.5mg 17β-oestradiol and 2.5mg dydrogesterone for the treatment of vasomotor symptoms: Results from a double-blind, controlled study. Maturitas 2010; 67:227-32. [DOI: 10.1016/j.maturitas.2010.07.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2010] [Revised: 07/02/2010] [Accepted: 07/02/2010] [Indexed: 10/19/2022]
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Abstract
BACKGROUND The aim of our study was to investigate the clearance of functional proteins by different low-density lipoprotein-apheresis (LDL-A) methods with the help of proteomic analyses. METHODS Proteins were eluated from the different LDL-A columns and investigated with 2D electrophoresis combined with mass spectrometry methods. In parallel, we quantified the plasma protein loss from patients treated with double-filtration plasmapheresis (DFPP; n = 9), direct adsorption of lipoproteins (DALI; n = 5) or heparin-induced extracorporeal LDL precipitation (HELP; n = 7) with routine laboratory methods and western blots. RESULTS Proteomic analyses of the column-bound proteins revealed a column-type-dependent loss with the highest number of protein spots in DALI-treated patients (1001 +/- 36), followed by HELP (881 +/- 25) and DFPP (535 +/- 20). More than 70 functional proteins were identified. These proteins are involved in the coagulation pathway (e.g. kininogen1) and have adhesive (e.g. fibronectin), rheological (e.g. fibrinogen) and immunological/inflammatory properties (e.g. complement components). Quantification with western blot analyses demonstrated a significant depletion (P < 0.01) of these proteins comparing serum samples before and after the column with a systemic lowering in patients' serum. CONCLUSIONS These data reveal strong interaction between column and serum proteins during LDL-A. The clearance of proteins with adhesive, rheological, and inflammatory characteristics may have beneficial effects on microcirculation and reduce chronic inflammation but may also concomitantly induce side effects such as an increased bleeding risk.
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Abstract
Environmental factors, in particular infections, have been linked with the risk of developing multiple sclerosis (MS). The association of Epstein—Barr virus infection with childhood onset of MS has been recently recognized. As other infections characteristically experienced during childhood have not yet been studied in larger cohorts of paediatric MS, we conducted a study on 152 German children with MS (age at onset <16 years) and matched controls in the hope of gaining evidence for their possible aetiological role in MS. Patterns of antibody responses were determined to a range of infections which, in prior studies principally on adult patients, had revealed possible associations with MS. In this study on children the serology of several infections showed associations with MS. In the exceptional case of Chlamydia pneumoniae there was a significantly higher prevalence of IgM antibody but, more typically, as in the case of influenza A, measles, parainfluenza 2, varicella/zoster viruses and particularly to the herpes simplex virus type 2 (HSV-2) lysate antigen, there were significantly higher concentrations of IgG antibody. Additional investigations, however, make it highly unlikely that a relevant number of children have experienced infections with HSV-2. In general this study supports and emphasizes a complex infectious and immunologic background of MS. Multiple Sclerosis 2008; 14: 136—139. http://msj.sagepub.com
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Effect of bleaching on subsurface micro-hardness of composite and a polyacid modified composite. Dent Mater 2007; 23:198-203. [PMID: 16546248 DOI: 10.1016/j.dental.2006.01.008] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2005] [Accepted: 01/10/2006] [Indexed: 10/24/2022]
Abstract
OBJECTIVE To investigate the influence of different bleaching techniques on subsurface physical properties of composite and polyacid modified composite tested via determination of micro-hardness. METHODS Specimens of Tetric Flow, Tetric EvoCeram and Compoglass were light cured (2.5mm thickness) and stored in artificial saliva for 2 weeks (n=12/group). The samples were only removed for application of the following bleaching agents in a humid atmosphere: Either Vivastyle (1h/d), Whitestrips (30min/d), sodium-perborate-water mixture (once for 72h), Simply White (1h/d), or Opalescence XtraBoost (1st and 5th day for 15min) were applied on the surfaces of the samples. Untreated specimens served as negative controls, samples treated with ethyl alcohol for 1h acted as positive controls. After the bleaching period, samples were cross-sectioned and the micro-hardness (Knoop) of different subsurface levels (0.1mm-2.0mm) was determined. RESULTS All bleaching techniques significantly reduced the Knoop-hardness of the restoratives compared to untreated controls. Thereby, bleaching significantly affected not only superficial but also the deep layers of the specimens: in superficial layers (0.1mm, 0.2mm) lowest micro-hardness values amounted to 69.5% and 76.3% of the respective untreated controls (Compoglass/Vivastyle). In deeper subsurface levels, the lowest hardness was observed with Opalescence/Tetric EvoCeram (0.3mm: 78.3%; 0.4mm: 80%; 0.5mm: 80.5%; 1.0mm: 84.2%; 2.0mm: 84.4%). SIGNIFICANCE Bleaching with the tested bleaching agents softens the adhesive restorative materials examined. Due to the fact that subsurface layers are also affected, polishing of the surface may not suffice for re-establishing the physical properties of the surface of the fillings.
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Abstract
We studied seroprevalence and concentrations of Epstein-Barr virus (EBV) antibodies in 147 pediatric patients with multiple sclerosis (MS) and paired controls. The children with MS showed a near-complete seropositivity for EBV antibody against virus capsid antigen (98.6% vs 72.1% in controls, p = 0.001) but did not display serologic evidence for a recent EBV infection. EBV antibody concentrations of pediatric patients with MS were significantly higher vs controls.
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Assessment of molecular events in squamous and non-squamous cell lung carcinoma. Lung Cancer 2006; 54:293-301. [DOI: 10.1016/j.lungcan.2006.08.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2006] [Revised: 08/09/2006] [Accepted: 08/17/2006] [Indexed: 10/24/2022]
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Influence of bleaching agents and desensitizing varnishes on the water content of dentin. Oper Dent 2006; 31:536-42. [PMID: 17024940 DOI: 10.2341/05-89] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
This in vitro study investigated the possible dehydration of dentin caused by bleaching agents. Furthermore, it tested whether protective dentin varnishes can maintain the physiological moisture of dentin during bleaching treatment. Fifty-five standardized dentin cylinders were prepared from freshly extracted bovine incisors under constant water irrigation. Prior to bleaching, the treatment specimens were conditioned at room temperature in a hygrophor for 14 days. The samples were divided into 11 groups. The Group A specimens, which were completely dehydrated, and Group B, which was stored for 2 weeks in a hygrophor, served as controls (A, B n=5). The other samples (n=10 each group) were coated with Vivasens [VS] (C), Bilfuorid [BF] (D) and Seal&Protect [SP] (E). Five specimens from each group (C-E) were subsequently treated with an experimental bleaching gel (Exp BG) (20% carbamide peroxide [CP], glycerine-based gel): Cb, Db, Eb. The remaining specimens were bleached with Exp BG (F) only, Vivastyle (G: 16% CP, glycerine-based gel) or Vivastyle Paint On (H: 6% CP-varnish) for 7 days (n=5 each group) with bleaching time for gels: 2 hours/day, paint on: 20 minutes/day. After the respective treatments, the overall water content of each specimen was determined using the analytical method of Karl-Fischer-titration. The water content of bovine dentin (Group B, mean%+/-SD) obtained in this study amounted to 15.24+/-0.4. All bleaching products significantly reduced the water content compared to the controls (exp BG: 13.32+/-0.47, Vivastyle 13.2+/-0.27, paint on 13.72+/-0.54; p<0.05). Also, application of SP before bleaching resulted in reduced water content (14.06+/-0.12; p=0.0005). However, bleaching with exp BG following use of VS (14.99+/-0.42) or SP (13.85+/-0.26) did not result in a reduction of water content in dentin. Pretreatment with BF did not protect dentin from water loss during bleaching (12.44+/-0.38; bi p=0.0009). All glycerine-based bleaching products used in this study had a significant dehydrating effect on dentin. The application of protective varnishes prior to bleaching treatment may reduce or even prevent dentin dehydration.
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Abstract
BACKGROUND Intradialytic hypotension (IDH) is one of the most severe complications during hemodialysis. Its appearance is caused in part by rapid fluid removal with concomitant failure in blood pressure regulation but also by other dialytic-dependent and independent factors. PATIENTS AND METHODS We investigated total (TBW), extracellular (ECW) and intracellular water (ICW) in chronic intermittent hemodialysis dialysis hypotension-prone (CRF-HP, n = 11) and nonhypotension-prone (CRF-NHP, n = 10) patients with end-stage renal disease before, every 30 minutes during, as well as after dialysis and within onset of intradialytic hypotension by multifrequent bioimpedance analysis (BIA). Additionally, intradialytic time course of BIA in patients with acute renal failure (ARF) and septic shock (n = 10) was observed. RESULTS IDH occurred in 72.1% of CRF-HP and in 80% of ARF patients. In CRF-HP and CRF-NHP, ECW significantly decreased by -12.44 +/- 4.22% in CRF-HP and -9.0 +/- 6.2% in CRF-NHP comparing pre- and post-dialysis values (each p < 0.01). Conversely, ICW increased by +11.5 +/- 11.3% in CRF-HP and +18.4 +/- 25.2% in CRF-NHP (each p < 0.05). In patients with ARF no significant changes could be detected. Calculated ECW/ICW and ECW/TBW ratio significantly decreased in CRF patients with a higher rate in CRF-HP patients (p < 0.05). Neither ECW/ICW nor ECW/TBW ratio correlated with mean arterial pressure. The onset of intradialytic hypotension (n = 35) did not differ intraindividually compared to normotensive periods (n = 411). Fluid removal in CRF patients seems to be mainly from the extracellular space. The reduced decreases in ECW/ICW and ECW/TBW ratios in CRF-HP compared to CRF-NHP may indicate an insufficient refilling from intra- to extracellular compartment in CRF-HP. CONCLUSION In conclusion, multifrequent BIA is not capable to predict hypotension in the individual patient during a particular dialysis session.
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Long-term follow-up after transoral laser microsurgery and adjuvant radiotherapy for advanced recurrent squamous cell carcinoma of the head and neck. Int J Radiat Oncol Biol Phys 2006; 65:1067-74. [PMID: 16750331 DOI: 10.1016/j.ijrobp.2006.03.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2005] [Revised: 02/02/2006] [Accepted: 03/09/2006] [Indexed: 10/24/2022]
Abstract
PURPOSE The aim of this study was to evaluate the efficacy of adjuvant radiotherapy after transoral laser microsurgery for advanced recurrent head-and-neck squamous cell carcinoma (HNSCC). PATIENTS AND METHODS Between 1988 and 2000, 37 patients with advanced local recurrences (23 local and 14 locoregional recurrences) of HNSCC without distant metastases were treated in curative intent with organ-preserving transoral laser microsurgery and adjuvant radiotherapy (before 1994 split-course radiotherapy with carboplatinum, after 1994 conventional radiotherapy). Initial therapy of the primary (8.1% oral cavity, 35.1% oropharynx, 13.5% hypopharynx, and 43.3% larynx) before relapse was organ-preserving transoral laser microsurgery without any adjuvant therapy. RESULTS After a median follow-up of 124 months, the 5-year overall survival rate was 21.3%, the loco-regional control rate 48.3%, respectively. In multivariate analysis, stage of original primary tumor (Stage I/II vs. Stage III/IV), and patient age (<58 years vs. >or=58 years) showed statistically significant impact on prognosis. In laryngeal cancer, larynx preservation rate after treatment for recurrent tumor was 50% during follow-up. CONCLUSION Our data show that organ-preserving transoral laser microsurgery followed by adjuvant radiotherapy is a curative option for patients who have advanced recurrence after transoral laser surgery and is an alternative to radical treatment.
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Changes of microvascular perfusion during acute ureteral obstruction in the rat kidney - the influence of gastrin releasing peptide. Clin Hemorheol Microcirc 2006; 34:519-28. [PMID: 16687791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
INTRODUCTION Peritubular renal microcirculation has not been directly visualized in acute ureteral obstruction. Therefore, we used epiilluminescence intravital microscopy and an animal model for the assessment of microvascular perfusion. MATERIALS AND METHODS In group 1 (n = 5) the left kidney of Wistar rats was exteriorized and placed on a heatable stage for microcirculatory analysis. FITC-dextran was injected for plasma staining. Microcirculatory stability of the model was assessed by a repeated intravital microscopy at baseline, 60, and 120 minutes. In detail, the functional peritubular vessel density (FVD, total vessel length per area in cm/cm(2)), the red blood cell velocities and diameters in/of arterioles and peritubular capillaries and the perfusion index were measured. In group 2 (n = 7) the left ureter was obstructed after baseline microscopy. In a third group (n = 6) the influence of the antidiuretic and vasoconstrictive peptide gastrin releasing peptide on peritubular microcirculation of the obstructed kidney was measured. RESULTS Repeated intravital microscopy did not induce major microcirculatory disturbances in group 1. Acute ureteral obstruction significantly decreased the index of peritubular perfusion. Moreover, FVD was found decreased at 120 minutes after a small rise at 60 minutes. Whereas blood cell velocities were not changed, arteriolar diameters were decreased after 120 minutes. GRP infusion lowered intrapelvic pressures at 60 and at 120 minutes. The transient increase of FVD (group 2) was not observed. The calculated peritubular flow remained nearly constant compared to a decrease in group 2. Histological assessment did not reveal any microscopy induced renal damage nor any differences between the groups. CONCLUSIONS (1) The model is stable for a time period of at least 120 minutes and allows for the direct visualization of the renal peritubular vessels. (2) Peritubular microcirculation shows a significant deterioration during ureteral obstruction. (3) Infusion of GRP may be beneficial for the microcirculation of the acutely obstructed kidney.
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Adjuvant radiotherapy after transoral laser microsurgery for advanced squamous carcinoma of the head and neck. Int J Radiat Oncol Biol Phys 2005; 63:1368-77. [PMID: 16169679 DOI: 10.1016/j.ijrobp.2005.05.027] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2004] [Revised: 04/27/2005] [Accepted: 05/11/2005] [Indexed: 11/29/2022]
Abstract
PURPOSE To evaluate the efficacy of an adjuvant radiotherapy after transoral laser microsurgery for advanced squamous cell carcinoma of the head and neck and to show that a less invasive surgery with organ preservation in combination with radiotherapy is an alternative to a radical treatment. PATIENTS AND METHODS Between 1987 and 2000, 208 patients with advanced squamous cell carcinoma of the head and neck were treated with postoperative radiotherapy after surgical CO2 laser resection. Primary sites included oral cavity, 38; oropharynx, 88; larynx, 36; hypopharynx, 46. Disease stages were as follows: Stage III, 40 patients; Stage IV, 168 patients. Before 1994, the treatment consisted of a split-course radiotherapy with carboplatinum (Treatment A). After 1994, the patients received a conventional radiotherapy (Treatment B). RESULTS Patients had 5-year locoregional control and disease-specific survival (DSS) rates of 68% and 48%, respectively. The 5-year DSS was 70% and 44% for Stages III and IV, respectively (p = 0.00127). Patients treated with a hemoglobin level greater or equal to 13.5 g/dL before radiotherapy had a 5-year DSS of 55% as compared with 39% for patients treated with a hemoglobin level greater than 13.5 g/dL (p = 0.0054). CONCLUSION In this series of patients with advanced head-and-neck tumors, transoral laser surgery in combination with adjuvant radiotherapy resulted in locoregional control and DSS rates similar to those reported for radical surgery followed by radiotherapy. Treatment B has clearly been superior to Treatment A. A further improvement of our treatment regimen might be expected by the combination of adjuvant radiotherapy with concomitant platinum-based chemotherapy.
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Expression of gastrin releasing Peptide receptor in renal cell carcinomas: a potential function for the regulation of neoangiogenesis and microvascular perfusion. J Urol 2005; 173:2154-9. [PMID: 15879878 DOI: 10.1097/01.ju.0000158135.26893.bc] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE Gastrin releasing peptide (GRP) is a growth factor for renal cell carcinoma (RCC) and it has vasoactive properties. Blockade of GRP receptor inhibits the growth of GRP receptor positive and negative tumors in nude mice, suggesting GRP effects other than those related to tumor epithelium. Therefore, in this study we analyzed the effects of GRP receptor blockade on neoangiogenesis in RCC. MATERIALS AND METHODS GRP receptor expression was determined in human RCC and corresponding normal tissue by real-time reverse transcriptase-polymerase chain reaction, immunohistochemistry and confocal laser scanning microscopy. Multicellular spheroids of the A498 RCC line were implanted into dorsal skin fold chambers of athymic nude mice. Neoangiogenesis was measured by intravital microscopy after blockade of GRP receptors by the GRP antagonist RC-3095. The influence of GRP on vascular endothelial growth factor secretion in A498 cells was studied in vitro. RESULTS GRP receptor expression was immunolocalized in tumor cells and microvessels. Implanted tumor cell spheroids and spheroid microvessels of the chamber also expressed GRP receptors. Spheroid neoangiogenesis was significantly inhibited by RC-3095 when given immediately after spheroid implantation. Vascular endothelial growth factor secretion of A498 cells was not affected by GRP. CONCLUSIONS RCC angiogenesis is sensitive to GRP receptor blockade. Therefore, GRP receptors may not only stimulate tumor cell proliferation, but also affect tumor microcirculation.
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Abstract
Whether physical activity increases risk or promotes progression of motor neurone degeneration in amyotrophic lateral sclerosis (ALS) is still debated. Current pathophysiological hypotheses include excitotoxicity, oxidative stress and increased calcium loads as causes of selective degeneration of vulnerable motor neurones. Vigorous exercise might amplify these factors by increasing firing rates at motor neurones. To test this hypothesis, we constrained a transgenic mouse model of ALS overexpressing the mutant human form of the Cu/Zn superoxide dismutase-1 (SOD-1) to a lifetime exercise on motor-driven running wheels for 10 h daily (active group, n = 12). Onset and progression of disease were assessed by grip strength, stride length and tight rope test. Data were compared with SOD-1 mice placed in running wheels set to slow speed (sedentary group, n = 13). Untreated SOD-1 mice were an additional control group (n = 12). We found no differences in disease onset, which was determined by a change-point analysis using an iterative fitting of segmented linear regression models, or in disease progression. However, the running group showed a non-significant 6-day improvement in survival (133.7 +/- 3.2 days) compared with the sedentary group (127.2 +/- 3.2 days) and a 4-day improvement compared with the control group (129.1 +/- 2.5 days). We demonstrate that a lifetime of vigorous exercise does not promote onset or progression of motor degeneration in SOD-1-mediated ALS. Moreover, the results suggest that the level of excitatory input and calcium turnover at motor neurones, both of which should be increased by running activity, do not interfere with the pathophysiology of SOD-1-mediated ALS.
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Microcirculation and excretory function of the liver under conditions of carbon dioxide pneumoperitoneum. Surg Endosc 2004; 18:1358-63. [PMID: 15803236 DOI: 10.1007/s00464-003-9252-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2003] [Accepted: 02/13/2004] [Indexed: 01/18/2023]
Abstract
BACKGROUND To date, the effects of increased abdominal pressure, as given during carbon dioxide (CO(2)) pneumoperitoneum, on hepatic microcirculation and biliary excretion are unknown. METHODS Using a custom-made peritoneal cavity chamber, we performed intravital microscopy of the left liver lobe under conditions of CO(2) pneumoperitoneum in a rat model. In addition, biliary excretion was assessed. RESULTS The establishment of a CO(2) pneumoperitoneum of 4 or 8 mmHg resulted in sinusoidal perfusion failure that was more pronounced in the periportal regions than in the midzonal and pericentral regions of the liver acinus. Biliary excretion was considerably reduced at an intraabdominal pressure of 8 mmHg. Leukocyte-endothelial cell interactions increased significantly in both hepatic sinusoids and postsinusoidal venules. CONCLUSION Alterations in hepatic microcirculation and liver function must be taken into consideration in any kind of laparoscopic surgery and may be of particular clinical relevance in patients with liver pathology.
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Abstract
BACKGROUND Alterations in the coronary circulation are important determinants of myocardial function. Few data are available, however, about microvascular changes in reactive hypertrophy. With MRI, serial determination of myocardial microcirculation after myocardial infarction (MI) is feasible. METHODS AND RESULTS We quantitatively determined myocardial perfusion and relative intracapillary blood volume using an MRI technique. Infarct size, myocardial mass, and left ventricular volumes were determined with cine MRI. Rats were investigated at 8, 12, and 16 weeks after MI (mean MI size 24.1+/-2.0%) or sham operation. Vasodilation was induced by adenosine. In the infarcted group, maximum perfusion decreased significantly from 8 to 16 weeks (5.6+/-0.3 versus 3.5+/-0.2 mL. g(-1). min(-1), P<0.01) compared with sham animals (5.5+/-0.3 versus 5.0+/-0.2 mL. g(-1). min(-1), P=0.17). Myocardial mass increased significantly (559.1+/-20.8 mg at 8 weeks versus 690.9+/-42.7 mg at 16 weeks, P<0.05) compared with sham-operated animals (516.3+/-41.7 versus 549.2+/-32.3 mg). Basal relative intracapillary blood volume increased significantly to 15.7+/-0.5 vol% at 8 weeks after MI and remained elevated (16.8+/-0.6 vol%) at 16 weeks compared with 12.1+/-0.3 vol% (P<0.01) in sham-operated rats. CONCLUSIONS Our results indicate that significant microvascular changes occur during cardiac remodeling. Hypoperfusion in the hypertrophied myocardium is related to an increase in vascular capacity, suggesting a compensatory vasodilatory response at the capillary level. These microvascular changes may therefore contribute to the development of heart failure.
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Myocardial perfusion and intracapillary blood volume in rats at rest and with coronary dilatation: MR imaging in vivo with use of a spin-labeling technique. Radiology 2000; 215:189-97. [PMID: 10751486 DOI: 10.1148/radiology.215.1.r00ap07189] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To validate a magnetic resonance (MR) imaging technique that is not first pass and that reveals perfusion and regional blood volume (RBV) in the intact rat. MATERIALS AND METHODS Measurement of perfusion was based on the perfusion-sensitive T1 relaxation after magnetic spin labeling of water protons. RBV was determined from steady-state measurements of T1 before and after administration of an intravascular contrast agent. The colored microsphere technique was used as a reference method for perfusion measurement. RBV and perfusion maps were obtained with the rats at rest and during administration of 3 mg of adenosine phosphate per kilogram of body weight per minute. RESULTS At MR imaging, perfusion during resting conditions was 3.5 mL/g/min +/- 0.1 (SEM), and RBV was 11.6% +/- 0.6 (SEM). Adenosine phosphate significantly increased perfusion to 4.5 mL/g/min +/- 0.3 (SEM) and decreased mean arterial pressure from 120 mm Hg to 65 mm Hg, which implies a reduction of coronary resistance to 40% of baseline. RBV increased consistently to 23.8% +/- 0.6 (SEM). CONCLUSION The study results show that quantitative mapping of perfusion and RBV may be performed noninvasively by means of MR imaging in the intact animal. The presented method allows determination of vasodilative and perfusion reserve, which reflects the in vivo regulation of coronary microcirculation for a given stimulus.
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Abstract
Measurement of regional blood volume (RBV) in the myocardium in vivo is important for the assessment of tissue viability and function. The method in this work is based on the acquisition of a T(1) map before and after intravascular contrast agent application. It is known that this method is influenced by perfusion that causes an overestimation of RBV values. In order to solve this problem, the new method is proposed which acquires T(1) maps with slice selective inversion pulses. Due to blood flow nonexcited spins enter the detection slice, which leads to an acceleration of the relaxation time. A model that divides tissue into two compartments is adapted to slice selective inversion in order to derive a simple expression for perfusion-corrected RBV. The aim of the study is to demonstrate the feasibility and accuracy of this technique for quantification of RBV in rat myocardium in vivo. RBV maps were obtained for five rats, and the reproducibility was determined by repeating the experiment several times. A mean RBV value of 12.8 +/- 0.7% (v/v) over all animals was obtained in the myocardium. The results were compared with RBV maps obtained with perfusion-sensitive RBV imaging in the same five rats and with first-pass RBV studies. In order to demonstrate the strength of the new method the vasodilator adenosine was administered and alterations in microcirculation were imaged. Magn Reson Med 42:500-506, 1999.
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In vivo quantitative mapping of cardiac perfusion in rats using a noninvasive MR spin-labeling method. J Magn Reson Imaging 1998; 8:1240-5. [PMID: 9848735 DOI: 10.1002/jmri.1880080610] [Citation(s) in RCA: 99] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Measurement of myocardial perfusion is important for the functional assessment of heart in vivo. Our approach is based on the modification of the longitudinal relaxation time T1 induced by magnetic spin labeling of endogenous water protons. Labeling is performed by selectively inverting the magnetization within the detection slice, and longitudinal relaxation is measured using a fast gradient echo MRI technique. As a result of blood flow, nonexcited spins enter the detection slice, which leads to an acceleration of the relaxation rate. Incorporating this phenomenon in a mathematical model that describes tissue as two compartments yields a simple expression that allows the quantification of perfusion from a slice-selective and a global inversion recovery experiment. This model takes into account the difference between T1 in blood and T1 in tissue. Our purpose was to evaluate the feasibility and reproducibility of this technique to map quantitatively myocardial perfusion in vivo in rats. Quantitative maps of myocardial blood flow were obtained from nine rats, and the reproducibility of the technique was evaluated by repeating the whole perfusion experiment four times. Evaluation of regions of interest within the myocardium yielded a mean perfusion value of 3.6 +/- .5 ml x min(-1) x g(-1) over all animals, which is in good agreement with previously reported literature values.
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Abstract
Many pathophysiological processes in the myocardium are in close relation to changes of the regional blood volume and regional myocardial blood flow or perfusion. Only few methods exist to obtain quantitative values for these parameters. Quantitative regional blood volume (RBV) studies in rat myocardium are presented using snapshot fast low angle shot (FLASH) inversion recovery T1 measurements with two different blood pool contrast agents, gadolinium diethylenetriaminopentaacetic acid (Gd-DTPA) albumin and Gd-DTPA polylysine. In contrast to previous attempts, each snapshot FLASH image acquisition was ECG-triggered under breathhold conditions. To measure relaxation times shorter than a heart cycle, each T1 sequence was repeated two times with different delays between inversion pulse and first image acquisition. The experiments were performed on a Bruker Biospec 70/21 using a homogeneous transmitter coil and a circularly polarized surface receiver coil, a special ECG trigger unit, and a respirator that is controlled by the pulse program. Based on a fast exchange model RBVm maps were calculated from the relaxation time maps for different concentrations of the two blood pool contrast agents. A significant dependence of the RBVm values on blood T1 was found. This is in accordance with a model that has been developed recently relating the dependence of RBVm on T1 of blood to perfusion. For Gd-DTPA albumin, the application of the model to the experimental data yields realistic values for RBV and perfusion. The values, which are in accordance with literature data, were obtained at highest contrast agent concentrations i.e., lowest relaxation times of blood (ca. 200 ms).
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Myocardial perfusion and capillary blood volume during left ventricular remodelling. MAGMA (NEW YORK, N.Y.) 1998; 6:148-9. [PMID: 9803393 DOI: 10.1007/bf02660941] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Functional magnetic resonance imaging in intact plants--quantitative observation of flow in plant vessels. Magn Reson Imaging 1998; 16:331-8. [PMID: 9621974 DOI: 10.1016/s0730-725x(97)00307-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Quantitative magnetic resonance (MR) images of flow velocities in intact corn plants were acquired using magnetization-prepared MR microscopy. A phase contrast flow imaging technique was used to quantitate water flow velocities and total volume flow rates in small xylem vessels. The simultaneous measurement of the transpiration of the whole plant was achieved by using a closed climate chamber within the MR magnet. The total volume flow rate and the transpiration values were in close correlation. Functional magnetic resonance imaging in intact plants was performed by light stimulation of the transpiration inside of the magnet. The change in the flow velocities in the xylem vessels of single vascular bundles was in correlation with the changes in the transpiration. Significant differences were observed between the xylem vessels in different vascular bundles. Furthermore, flow velocity measurements were performed on excised plant stems and visualized by the uptake of the MR contrast agent, gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA). A comparison between the phase contrast flow imaging and the contrast media uptake showed to be in good agreement with each other.
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