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1.
Physiol Res ; 72(S4): S381-S387, 2023 12 17.
Article in English | MEDLINE | ID: mdl-38116776

ABSTRACT

Spontaneous preterm birth (sPTB) is a major cause of perinatal morbidity and mortality, even in developed countries. Prediction of sPTB is therefore a valuable tool to reduce the associated risks. The current standard for the prediction of sPTB consists, in addition to anamnestic data, of previous sPTB and previous second trimester miscarriage, measurement of cervical length by transvaginal ultrasound (TVU CL) together with assessment of fetal fibronectin levels in cervicovaginal fluid. Other evaluation parameters, such as the level of endocannabinoids in the pregnant woman's blood, could increase the sensitivity of this management. Endocannabinoids (eCBs) are a part of the endocannabinoid system (ECS); out of them anandamide (arachidonoyl-ethanolamide, AEA), in particular, plays an important role in the regulation of pregnancy and childbirth. We present the protocol for an open, non-randomized study to evaluate concentrations of AEA and other endocannabinoids: 2 linoleoylglycerol (2-AG), 2 linoleoylglycerol (2-LG), 2 oleoylglycerol (2-OG), and 2 arachidonoyldopamine (2-ADOPA or also NADA) in the blood of pregnant women as potential predictors of sPTB. In a total of 230 women with a history of sPTB or miscarriage, eCBs levels between 22 and 28 weeks of gestation will be assessed from maternal blood, in addition to the standard procedure. The aim of the study is to determine the relationship between blood concentrations of the endocannabinoids tested and the risk of sPTB. The results of this study will describe the prognostic significance of maternal blood eCBs levels for sPTB, and could subsequently enable improved screening programs for early identification of sPTB.


Subject(s)
Abortion, Spontaneous , Premature Birth , Infant, Newborn , Pregnancy , Female , Humans , Premature Birth/diagnosis , Endocannabinoids , Pregnancy Trimester, Second
2.
Epidemiol Mikrobiol Imunol ; 68(1): 3-8, 2019.
Article in English | MEDLINE | ID: mdl-31181946

ABSTRACT

OBJECTIVES: To follow on the epidemiology of HCV, especially genotypes spreading among people who inject drugs (PWID) in Prague and surrounding Central Bohemia, Czech Republic. METHODS: 546 patients who reported past and/or recent injecting of drugs were recruited in the years 2010-2012. They were initially tested for anti-HCV. Real-time PCR was used for quantification and genotyping of hepatitis C virus. Obtained data from the years 2010-2012 were compared with historical controls from periods of 1998-2000 and 2005-2007. RESULTS: Of 546 initially recruited and tested patients were 393 (72%) anti-HCV seropositive and of them 269 (68.4%) had detectable HCV PCR RNA. The most prevalent subtype was 3a in 97 patients (36.1%), 1a was detected in 85 patients (31.6%) and 1b in 57 patients (21.2%). These three genotypes were responsible for nearly 89% of infections. CONCLUSION: Significant increase in both genotypes 1a and 3a over the 15 years was apparent and significant, followed by the decrease in genotype 1b. In the genotype 1b and genotype 3a the significance has risen with the years of data collection. Described genotypic shift reflects the evolution of HCV epidemics and corresponds with the mode of transmission.


Subject(s)
Genotype , Hepacivirus , Hepatitis C , Czech Republic/epidemiology , Hepatitis C/epidemiology , Hepatitis C/genetics , Humans , Prevalence
3.
Eur J Med Chem ; 143: 843-853, 2018 Jan 01.
Article in English | MEDLINE | ID: mdl-29223099

ABSTRACT

A library of thirty two 3,4-diphenylfuranones related to both combretastatin A-4 and antifungal 5-(acyloxymethyl)-3-(halophenyl)-2,5-dihydrofuran-2-ones was prepared. Cytotoxic effects on a panel of cancer and normal cell lines and antiinfective activity were evaluated, and the data were complemented with tests for the activation of caspase 3 and 7. High cytotoxicity was observed in some of the halogenated analogues, eg. 3-(3,4-dichlorophenyl)-4-(4-methylphenyl)-2,5-dihydrofuran-2-one with IC50 0.12-0.23 µM, but the compounds were also highly toxic against non-malignant control cells. More importantly, notable antibacterial activity indicating G+ selectivity has been found in the 3,4-diarylfuranone class of compounds for the first time. Hydroxymethylation of furanone C5 knocked out cytotoxic effects (up to 40 µM) while maintaining significant activity against Staphylococcus strains in some derivatives. MIC95 of the most promising compound, 3-(4-bromophenyl)-5,5-bis(hydroxymethyl)-4-(4-methylphenyl)-2,5-dihydrofuran-2-one against S. aureus strain ATCC 6538 was 0.98 µM (0.38 µg/mL) and 3.9 µM (1.52 µg/mL) after 24 and 48 h, respectively.


Subject(s)
Anti-Bacterial Agents/pharmacology , Antifungal Agents/pharmacology , Bacteria/drug effects , Fungi/drug effects , Furans/pharmacology , Anti-Bacterial Agents/chemical synthesis , Anti-Bacterial Agents/chemistry , Antifungal Agents/chemical synthesis , Antifungal Agents/chemistry , Apoptosis/drug effects , Cell Proliferation/drug effects , Cell Survival/drug effects , Cells, Cultured , Dose-Response Relationship, Drug , Furans/chemical synthesis , Furans/chemistry , Humans , Microbial Sensitivity Tests , Molecular Structure , Structure-Activity Relationship
4.
Analyst ; 141(15): 4554-7, 2016 Aug 07.
Article in English | MEDLINE | ID: mdl-27353221

ABSTRACT

The transfer of protons or proton donor/acceptor abilities is an important phenomenon in many biomolecular systems. One example is the recently proposed peptidic proton-wires (H-wires), but the ability of these His-containing peptides to transfer protons has only been studied at the theoretical level so far. Here, for the first time the proton transfer ability of peptidic H-wires is examined experimentally in an adsorbed state using an approach based on a label-free electrocatalytic reaction. The experimental findings are complemented by theoretical calculations at the ab initio level in a vacuum and in an implicit solvent. Experimental and theoretical results indicated Ala3(His-Ala2)6 to be a high proton-affinity peptidic H-wire model. The methodology presented here could be used for the further investigation of the proton-exchange chemistry of other biologically or technologically important macromolecules.


Subject(s)
Peptides/chemistry , Protons , Histidine , Solvents
5.
Open Neurol J ; 9: 9-14, 2015.
Article in English | MEDLINE | ID: mdl-26157520

ABSTRACT

A high serum level of homocysteine, known as hyperhomocystenemia (HHcy) is associated with vascular dysfunction such as altered angiogenesis and increased membrane permeability. Epidemiological studies have found associations between HHcy and Alzheimer's disease (AD) progression that eventually leads to vascular dementia (VaD). VaD is the second most common cause of dementia in people older than 65, the first being AD. VaD affects the quality of life for those suffering by drastically decreasing their cognitive function. VaD, a cerebrovascular disease, generally occurs due to cerebral ischemic events from either decreased perfusion or hemorrhagic lesions. HHcy is associated with the hallmarks of dementia such as tau phosphorylation, Aß aggregation, neurofibrillary tangle (NFT) formation, neuroinflammation, and neurodegeneration. Previous reports also suggest HHcy may promote AD like pathology by more than one mechanism, including cerebral microangiopathy, endothelial dysfunction, oxidative stress, neurotoxicity and apoptosis. Despite the corelations presented above, the question still exists - does homocysteine have a causal connection to AD? In this review, we highlight the role of HHcy in relation to AD by discussing its neurovascular effects and amelioration with dietary supplements. Moreover, we consider the studies using animal models to unravel the connection of Hcy to AD.

6.
Transplant Proc ; 46(5): 1536-9, 2014 Jun.
Article in English | MEDLINE | ID: mdl-24935326

ABSTRACT

Gastrointestinal ischemia after allogeneic bone marrow transplantation is a rare complication not well-described in the literature. Herein we retrospectively review charts of four patients who developed intestinal ischemia after allogeneic bone marrow transplantation at our institution. The patients were found to be predominately younger males who presented with nonspecific abdominal pain. Graft-versus-host disease was a common finding among all patients. Laboratory values suggestive of microangiopathy were present in two patients. Obesity and hypertriglyceridemia were cardiovascular risk factors found in these patients. The development of thrombotic microangiopathy and cardiovascular risk factors after allogeneic bone marrow transplantation may predispose patients to gastrointestinal ischemia and may portend a poor prognosis.


Subject(s)
Intestines/blood supply , Ischemia/etiology , Stem Cell Transplantation/adverse effects , Adult , Female , Humans , Male , Middle Aged , Young Adult
7.
J Pharm Biomed Anal ; 51(2): 464-70, 2010 Jan 20.
Article in English | MEDLINE | ID: mdl-19410410

ABSTRACT

A new extraction technique based on the off-line combination of pressurized-liquid with solid-phase extraction (PLE-SPE) is described. The method was used for the extraction of bioactive phenolic acids (protocatechuic, p-hydroxybenzoic, 2,3-dihydroxybenzoic, chlorogenic, vanillic, caffeic, p-coumaric, salicylic acid), cinnamic acid and hydroxybenzaldehydes (p-hydroxybenzaldehyde, 3,4-dihydroxybenzaldehyde, vanillin) from in vitro culture of two freshwater algae (Anabaena doliolum and Spongiochloris spongiosa) and from food products of marine macroalgae Porphyra tenera (nori) and Undaria pinnatifida (wakame). For the identification and quantification of the compounds the molecular ions [M-H](-) and specific fragments were analyzed by quadrupole mass spectrometry analyzer connected on-line with a reversed-phase HPLC system. Our analysis showed that the freshwater algae and marine algal products contained submicrogram or microgram level of above-mentioned phenols per gram of lyophilized sample. In addition, the total phenol content (Folin-Ciocalteu assay) and antioxidant activity (TEAC assay, Trolox equivalent antioxidant capacity assay) of the PLE-SPE extracts were determined and discussed.


Subject(s)
Antioxidants/analysis , Chromatography, High Pressure Liquid/methods , Eukaryota/chemistry , Online Systems , Phenols/analysis , Solid Phase Extraction/methods , Antioxidants/chemistry , Benzoic Acid/analysis , Benzoic Acid/chemistry , Cinnamates/analysis , Cinnamates/chemistry , Freshwater Biology/methods , Phenols/chemistry , Reference Standards , Seawater/chemistry
8.
J Chromatogr A ; 1216(5): 763-71, 2009 Jan 30.
Article in English | MEDLINE | ID: mdl-19111311

ABSTRACT

In the present paper a new extraction technique based on the combination of solid-phase/supercritical-fluid extraction (SPE/SFE) with subsequent reversed-phase HPLC is described. The SPE/SFE extractor was originally constructed from SPE-cartridge incorporated into the SFE extraction cell. Selected groups of benzoic acid derivatives (p-hydroxybenzoic, protocatechuic, gallic, vanillic and syringic acid), hydroxybenzaldehydes (4-hydroxybenzaldehyde and 3,4-dihydroxybenzaldehyde) and cinnamic acid derivatives (o-coumaric, p-coumaric, caffeic, ferulic, sinapic and chlorogenic acid) were extracted. Cyclic addition of binary extraction solvent system based on methanol:water (1:1, v/v) and methanol/ammonia aqueous solution was used for extraction at 40MPa and 80 degrees C. The p-hydroxybenzoic, protocatechuic, vanillic, syringic, caffeic and chlorogenic acid; 4-hydroxybenzaldehyde and 3,4-dihydroxybenzaldehyde were identified by HPLC-electrospray mass spectrometry in SPE/SFE extracts of acid hydrolyzates of microalga (Spongiochloris spongiosa) and cyanobacterial strains (Spirulina platensis, Anabaena doliolum, Nostoc sp., and Cylindrospermum sp.). For the identification and quantification of the compounds the quasi-molecular ions [M-H](-) and specific fragments were analysed by quadrupole mass spectrometry analyzer. Our analysis showed that the microalgae and cyanobacteria usually contained phenolic acids or aldehydes at microg levels per gram of lyophilized sample. The proposed SPE/SFE extraction method would be useful for the analysis of different plant species containing trace amount of polar fraction of phenols.


Subject(s)
Chlorophyta/chemistry , Cyanobacteria/chemistry , Phenols/analysis , Solid Phase Extraction/methods , Aldehydes/analysis , Aldehydes/chemistry , Chromatography, High Pressure Liquid , Equipment Design , Kinetics , Methanol/chemistry , Phenols/chemistry , Pressure , Reproducibility of Results , Spectrometry, Mass, Electrospray Ionization , Temperature
9.
Ceska Slov Farm ; 57(2): 85-94, 2008 Apr.
Article in Czech | MEDLINE | ID: mdl-18578418

ABSTRACT

Isoflavones belong to the natural substances exhibiting a number of physiological effects in living organisms. The substances are synthesized in plant tissues as protective agents against biotic stress (i.e. bacterial infection). Isoflavones are also an important dietary constituent in human nutrition. The review discusses modern trends in the studies of isoflavones in plant materials and foodstuffs and procedures for chemical analyses of isoflavones in human body fluids and plant tissues. Highly effective extraction and purification techniques, i.e. solid-phase extraction (SFE), accelerated-solvent extraction (ASE), and Soxhlet extraction, are presented. Latest procedures in chromatographic separation of isoflavones that apply different types of stationary phases are described. Immunochemical analysis, electrochemical sensing of isoflavones, spectrometric and other analytical techniques and their applications are also mentioned. Special attention is focused on a highly selective and sensitive technique of mass spectrometry and its application for identification of isoflavones and their glucosides in plants. Studies of interactions of isoflavones with cell receptors and a number of biologically active substances such as DNA and proteins are described. The reason for the presentation of the review was not to give a full overview of the presented topics but mainly to show modern and the most recent methods in the studies of isoflavones.


Subject(s)
Chemistry Techniques, Analytical/methods , Isoflavones/analysis , Chemistry Techniques, Analytical/instrumentation , Humans , Isoflavones/chemistry , Isoflavones/isolation & purification
10.
J Chromatogr A ; 1195(1-2): 52-9, 2008 Jun 27.
Article in English | MEDLINE | ID: mdl-18501366

ABSTRACT

Complete separation of aglycones and glucosides of selected isoflavones (genistin, genistein, daidzin, daidzein, glycitin, glycitein, ononin, sissotrin, formononetin, and biochanin A) was possible in 1.5 min using an ultrahigh-pressure liquid chromatography (U-HPLC) on a different particular chemically modified stationary phases with a particle size under 2 microm. In addition, selected separation conditions for simultaneous determination of isoflavones together with a group of phenolic acids (gallic, protocatechuic, p-hydroxybenzoic, vanillic, caffeic, syringic, p-coumaric, ferulic, and sinapic acid) allowed separation of all 19 compounds in 1.9 min. Separations were conducted on a non-polar reversed phase (C(18)) and also on more polar phases with cyanopropyl or phenyl groups using a gradient elution with a mobile phase consisting of 0.3% aqueous acetic acid and methanol. Chromatographic peaks were characterised using parameters such as resolution, symmetry, selectivity, etc. Individual substances were identified and quantified using UV-vis diode array detector at wavelength 270 nm. Limits of detection (3S/N) were in the range 200-400 pg ml(-1). Proposed U-HPLC technique was used for separation of isoflavones and phenolic acids in samples of plant materials (Trifolium pratense, Glycine max, Pisum sativum and Ononis spinosa) after acid hydrolysis of the samples and modified Soxhlet extraction.


Subject(s)
Chromatography, High Pressure Liquid/methods , Hydroxybenzoates/isolation & purification , Isoflavones/isolation & purification , Caffeic Acids/chemistry , Caffeic Acids/isolation & purification , Coumaric Acids/chemistry , Coumaric Acids/isolation & purification , Gallic Acid/analogs & derivatives , Gallic Acid/chemistry , Gallic Acid/isolation & purification , Genistein/chemistry , Genistein/isolation & purification , Hydroxybenzoates/chemistry , Isoflavones/chemistry , Molecular Structure , Pisum sativum/chemistry , Plant Extracts/chemistry , Plant Extracts/isolation & purification , Propionates , Glycine max/chemistry , Trifolium/chemistry , Vanillic Acid/chemistry , Vanillic Acid/isolation & purification
11.
Anal Bioanal Chem ; 389(7-8): 2277-85, 2007 Dec.
Article in English | MEDLINE | ID: mdl-17899029

ABSTRACT

A rapid-resolution HPLC/UV-VIS DAD separation method (which takes <1 min) for the determination and identification of genistin, genistein, daidzein, daidzin, glycitin, glycitein, ononin, formononetin, sissotrin and biochanin A in fmol quantities in submicroliter sample volumes was optimized. A linear gradient elution (0 min 22% B, 1.0 min 80% B, 1.4 min 100% B, 1.8 min 22% B) using a mobile phase containing 0.2 % (v/v) acetic acid (solvent A) and methanol (solvent B) was applied on a Zorbax SB C18 column (1.8 microm particle size) at 80 degrees C. The method was verified using samples of bits of soy and methanolic extracts from Trifolium pratense, Iresine herbstii and Ononis spinosa plants. Pseudobaptigenin glucoside, irilone, prunetin, texasin, tlatlancuayin and other isoflavones, in addition to aglycones of isoflavones and their beta-glucosides and malonyl and acetyl derivatives, were identified by UV-VIS DAD and electrospray mass spectrometric (ESI-MS) detection in the extracts.


Subject(s)
Chromatography, High Pressure Liquid/methods , Glycine max/chemistry , Isoflavones/analysis , Plant Extracts/chemistry , Plant Preparations/chemistry , Isoflavones/chemistry , Methanol/chemistry , Molecular Structure , Spectrometry, Mass, Electrospray Ionization , Spectrophotometry , Time Factors
12.
J Agric Food Chem ; 55(15): 6147-53, 2007 Jul 25.
Article in English | MEDLINE | ID: mdl-17608493

ABSTRACT

Influence of saccharose in the presence or absence of polyethylene glycol (PEG), methyl jasmonate, and an inactivated bacterial culture of Agrobacterium tumefaciens in cultivation medium on morphology of Hypericum perforatum L. and production of hypericin and hyperforin was studied under in vitro conditions. Production of hypericin and hyperforin was influenced by the presence of different concentrations of saccharose (10-30 g L(-1)) in cultivation medium. Addition of PEG (1.25-5 g L(-1)) in the presence of saccharose (10-30 g L(-1)) increased production of hypericin and hyperforin in the H. perforatum in vitro culture. Synthesis of hypericin and hyperforin was unchanged or reduced for most of the experimental plants at higher contents of PEG (10 and 15 g L(-1)). Concentrations of hypericin and hyperforin in the H. perforatum were on the order 100 and 103 microg g(-1) of dry plant material, respectively. Production of hypericin and hyperforin was stimulated either in the presence of a chemical elicitor (methyl jasmonate) or an inactivated bacterial culture of A. tumefaciens. Morphological changes induced by the abovementioned substances were observed and described in detail. The obtained results will be applied in experimental botany and in the technology of H. perforatum cultivation for pharmaceutical applications.


Subject(s)
Agrobacterium tumefaciens/metabolism , Hypericum/metabolism , Perylene/analogs & derivatives , Phloroglucinol/analogs & derivatives , Polyethylene Glycols/pharmacology , Sucrose/pharmacology , Terpenes/metabolism , Acetates/pharmacology , Anthracenes , Bridged Bicyclo Compounds/metabolism , Cyclopentanes/pharmacology , Hypericum/growth & development , Oxylipins , Perylene/metabolism , Phloroglucinol/metabolism , Seeds/growth & development , Seeds/metabolism
13.
Ceska Slov Farm ; 56(2): 62-6, 2007 Apr.
Article in Czech | MEDLINE | ID: mdl-17619301

ABSTRACT

St. John's Wort (Hypericum perforatum L.) is commonly accepted as a medicinal plant. The data on the physiological activities of the individual substances that are produced in different organs of H. perforatum are well known at present. The highest attention is focused on the characterization and phytochemical properties of hypericin and hyperforin. These organic compounds are used as antidepressant, anticarcinogenic (photodynamic), antimicrobial and virostatic agents. The review paper surveys the present knowledge of chemical and analytical methods for their identification and quantification, physiological activity, and pharmacological and biomedical applications of hypericin and hyperforin.


Subject(s)
Hypericum/chemistry , Perylene/analogs & derivatives , Phloroglucinol/analogs & derivatives , Plant Extracts/pharmacology , Plants, Medicinal/chemistry , Terpenes/pharmacology , Anthracenes , Antidepressive Agents/therapeutic use , Bridged Bicyclo Compounds/isolation & purification , Bridged Bicyclo Compounds/pharmacology , Bridged Bicyclo Compounds/therapeutic use , Depressive Disorder/drug therapy , Humans , Perylene/isolation & purification , Perylene/pharmacology , Perylene/therapeutic use , Phloroglucinol/isolation & purification , Phloroglucinol/pharmacology , Phloroglucinol/therapeutic use , Phytotherapy , Plant Extracts/isolation & purification , Plant Extracts/therapeutic use , Terpenes/isolation & purification , Terpenes/therapeutic use
14.
Eur J Echocardiogr ; 3(1): 44-6, 2002 Mar.
Article in English | MEDLINE | ID: mdl-12067533

ABSTRACT

AIMS: Visual analysis of ejection fraction by echocardiography (echo) is commonly performed, but little data exists regarding consistency among interpreters. We postulate that an active echo group evolves a standard to which interpreters cluster, with variation or 'drift' occurring at satellite sites distant from the main practice centre. Assuming that echo ejection fraction follows a normal distribution, average ejection fraction for high volume readers should be similar. METHODS AND RESULTS: From May 1997 to June 1999, 8187 echoes were read by 16 (average 512) readers of a single practice at several sites. Composite and individual ejection fraction (visual estimate) means and standard deviations were compared. Composite ejection fraction was 54.17+/-11.35. Mean ejection fraction varied significantly overall among readers (P<0.0001) with 37 comparisons between individual readers being significantly different (P<0.05). However, analysis suggested that these individual differences involved only five readers, four of whom practised at satellite sites. If these five readers were excluded, no significant individual differences were seen (n=6202). If only the four satellite readers were excluded, just four significant individual differences were seen (n=6915). CONCLUSIONS: (1) Within a busy single practice site, mean echo ejection fraction is very similar, suggesting a self-evolved practice standard that is consistently adhered to. (2) 'Drift' or variability is seen at smaller satellite sites, perhaps due to less exposure to the echo interpretations of others. (3) This type of analysis may provide a useful quality assurance tool for echo laboratories.


Subject(s)
Echocardiography , Stroke Volume , Cardiology , Humans , Observer Variation , Professional Practice Location
15.
Aviat Space Environ Med ; 72(7): 647-51, 2001 Jul.
Article in English | MEDLINE | ID: mdl-11471908

ABSTRACT

BACKGROUND: Attitudes toward fairness and effectiveness of mandatory drug testing vary within pilot populations (4,8) as well as other populations (3). This descriptive-correlational study examined civilian student pilots' attitudes toward urinalysis (UA) drug testing over a 10-yr period and the pilots' opinions regarding effectiveness, adequacy, and fairness of the testing as a deterrent for substance abuse among pilots. METHODS: A sample of three different groups of civilian aviation students (n = 314), consisted of 103 pilots studied prior to implementing a mandatory drug testing program, 113 pilots studied 1 yr after implementing a mandatory drug testing program, and 98 pilots studied 6 yr into a mandatory drug testing program. A 14-item questionnaire (alpha = 0.74), indicating degrees of agreement, was completed by the student pilots who were enrolled in a large civilian pilot training program. RESULTS: There were no significant differences among the study pilots' feelings related to anxiety of drug testing when comparing non-mandatory and mandatory groups over time. The pilots continue to believe that alcohol use by pilots within this civilian piloting training program has decreased since testing was mandated and that drug use also showed a significant decrease (p = 0.01), although not as significant (p = 0.0001) as the decrease in alcohol use. CONCLUSION: The study showed that alcohol and drug testing is more generally accepted by the pilots in the study as the decade of the 1990s came to a close.


Subject(s)
Aviation/trends , Health Knowledge, Attitudes, Practice , Substance Abuse Detection/psychology , Substance-Related Disorders/urine , Adult , Female , Humans , Male , Substance Abuse Detection/methods , Surveys and Questionnaires
16.
Proc Natl Acad Sci U S A ; 98(10): 5481-6, 2001 May 08.
Article in English | MEDLINE | ID: mdl-11331744

ABSTRACT

Classical molecular dynamics is applied to the rotation of a dipolar molecular rotor mounted on a square grid and driven by rotating electric field E(nu) at T approximately 150 K. The rotor is a complex of Re with two substituted o-phenanthrolines, one positively and one negatively charged, attached to an axial position of Rh(2)(4+) in a [2]staffanedicarboxylate grid through 2-(3-cyanobicyclo[1.1.1]pent-1-yl)malonic dialdehyde. Four regimes are characterized by a, the average lag per turn: (i) synchronous (a < 1/e) at E(nu) = /E(nu)/ > E(c)(nu) [E(c)(nu) is the critical field strength], (ii) asynchronous (1/e < a < 1) at E(c)(nu) > E(nu) > E(bo)(nu) > kT/mu;, [E(bo)(nu) is the break-off field strength], (iii) random driven (a approximately 1) at E(bo)(nu) > E(nu) > kT/mu, and (iv) random thermal (a approximately 1) at kT/mu > E(nu). A fifth regime, (v) strongly hindered, W > kT, E(mu), (W is the rotational barrier), has not been examined. We find E(bo)(nu)/kVcm(-1) approximately (kT/(mu))/kVcm(-1) + 0.13(nu/GHz)(1.9) and E(c)(nu)/kVcm(-1) approximately (2.3kT/(mu))/kVcm(-1) + 0.87(nu/GHz)(1.6). For nu > 40 GHz, the rotor behaves as a macroscopic body with a friction constant proportional to frequency, eta/eVps approximately 1.14 nu/THz, and for nu < 20 GHz, it exhibits a uniquely molecular behavior.

17.
Chest ; 119(1): 271-6, 2001 Jan.
Article in English | MEDLINE | ID: mdl-11157614

ABSTRACT

Digital echocardiography has evolved rapidly during the last decade, and the all-digital echocardiographic laboratory has just reached the threshold of reality. This review article explains what this transition means for the modern medical practice and concisely presents what a digital echocardiogram is, the technical aspects of digital image acquisition and processing, and the advantages and limitations of digital echocardiography vs analog echocardiography. This review should serve as a useful source of information for the general cardiologist not working closely with digital echocardiography, as well as a resource for the noncardiologist.


Subject(s)
Echocardiography/instrumentation , Image Processing, Computer-Assisted/instrumentation , Radiology Information Systems/instrumentation , Equipment Design , Humans , Sensitivity and Specificity
18.
Compr Ther ; 26(4): 269-75, 2000.
Article in English | MEDLINE | ID: mdl-11126098

ABSTRACT

Understanding of the mechanisms, outcomes and treatment of non-Q wave myocardial infarction (NQMI) has evolved. Coexisting diabetes poses additional challenges. We studied baseline characteristics, in-hospital and one-year outcomes for NQMI patients having percutaneous transluminal angioplasty.


Subject(s)
Angioplasty, Balloon, Coronary , Diabetes Complications , Myocardial Infarction/therapy , Aged , Analysis of Variance , Angioplasty, Balloon, Coronary/mortality , Female , Follow-Up Studies , Humans , Kansas/epidemiology , Male , Myocardial Infarction/complications , Myocardial Infarction/epidemiology , Risk Factors , Survival Analysis , Treatment Outcome
19.
J Am Soc Echocardiogr ; 13(12): 1109-16, 2000 Dec.
Article in English | MEDLINE | ID: mdl-11119279

ABSTRACT

Acquisition, interpretation, and storage of digital echocardiographic images has many advantages over the standard videotape-based method. Archival, transmission, and comparative interpretation are all optimized with digital echocardiography. A study performed at one site can be immediately available for viewing and analysis at another site by means of standard data transfer technology. Echocardiograms can be interpreted in the context of prior studies, which are readily available for side-by-side comparison. The transition to an all-digital laboratory involves the commitment of persons at multiple levels in the cardiology practice, including administrators, information technology specialists, sonographers, and physicians. Quality of patient care, use of physicians' and sonographers' time, and long-term financial benefit are all areas where improvement may be realized with the use of digital echocardiography. We present our experience in the development of an all-digital echocardiography laboratory, and we conclude that digital echo-cardiography is practical and can be implemented readily in a clinical setting. We performed several correlative analyses during this transition to validate the consistency and accuracy of digital interpretation compared with those of analog methods. The transition process from analog (videotape) to digital, including full wide area network exchange, took approximately 8 months. As technology advances, issues surrounding storage, comparison, and acquisition formats will continue to develop. We hope that our experience will help others make the transition to the digital environment and benefit from the ease of image access, the ability to comparatively interpret echocardiograms, and the superior image quality afforded by this advancement.


Subject(s)
Echocardiography , Medical Records Systems, Computerized/organization & administration , Attitude of Health Personnel , Cardiology/methods , Computer Communication Networks , Humans , Medical Records Systems, Computerized/standards , Private Practice , Radiology Information Systems
20.
Postgrad Med ; 108(2): 142, 145, 2000 Aug.
Article in English | MEDLINE | ID: mdl-10951753
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