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At least 73 records · Page 4Linked to original sources
PubMed1999

Cultivation of Tetrahymena thermophila in a 1.5-m3 airlift bioreactor.

A large-scale cultivation system for the mass cell production and extraction of the protozoon Tetrahymena thermophila has been developed on the basis of a low-cost complex nutrient medium. Cell growth and the production of extracellular proteases were investigated using a 15-l stirred-tank reactor and 13-l and 1500-l airlift reactors. Processes using defined and complex medium formulations were compared. After cell mass production by 1200 l cell suspension in the large airlift bioreactor, two different extraction methods, based on the use of an extraction decanter and a sedimentation procedure, were compared and followed by cell lyophilization. Cell sedimentation was shown to be the more efficient extraction method as it enabled cell retention/separation while preserving the cell structure. Maximum cell growth was achieved in the stirred-tank bioreactor, supporting the hypothesis that higher shear forces reduce the particle size of the medium, which is responsible for an optimized nutrient supply. The highest glucose uptake rates were found in defined medium lacking the nutrient particles that are present in complex medium formulations. The cell-specific proteolytic activity in culture supernatants of airlift bioreactors using complex medium conditions was higher than that of a culture broth with cells grown under defined medium formulations.

Animals↗
PubMed2001

Application of pressure steps to mechanosensitive channels in membrane patches: a simple, economical, and fast system.

Mechanosensitive channels (MSCs) have been described in a wide variety of cells, but the molecular mechanisms that couple membrane tension or deformation to channel activity (i.e., mechanotransduction) are not understood. The ability to measure the dynamics of the temporal relationship between the pressure stimulus and the channel response is a key tool for gaining insight into mechanotransduction. Several laboratories have designed pressure clamps, but these instruments are complex, costly, and not commercially available. This paper describes a simple and inexpensive system for applying fast pressure steps to a membrane patch. This system is easy to build and achieves submillisecond 20% to 80% step response times on par with the fastest pressure clamp described. Application to a stretch-activated non-selective cation channel in the kidney is used to demonstrate the system.

Ambystoma↗
PubMed2025

Integrating multi-omics approaches in acute myeloid leukemia (AML): Advancements and clinical implications.

Acute myeloid leukemia (AML) is a highly heterogeneous and aggressive hematologic malignancy characterized by clonal proliferation of myeloid precursors. Despite significant advancements in genomic profiling and targeted therapies, patient outcomes remain suboptimal due to disease complexity, resistance mechanisms, and high relapse rates. The integration of multi-omics approaches-spanning genomics, epigenomics, transcriptomics, proteomics, and metabolomics-has revolutionized AML research, offering a comprehensive understanding of leukemogenesis, tumor heterogeneity, and therapeutic vulnerabilities. Recent studies leveraging high-throughput sequencing, mass spectrometry, and advanced computational tools have uncovered novel biomarkers, clonal evolution dynamics, and microenvironmental interactions that drive AML progression and resistance. For instance, single-cell multi-omics has revealed chemotherapy-resistant leukemic stem cell populations, while proteogenomic analyses have identified actionable targets such as MCL1 and metabolic dependencies like OXPHOS. Clinically, integrated omics platforms are refining risk stratification, minimal residual disease (MRD) monitoring, and personalized therapy selection. However, challenges such as data integration complexity, cost barriers, and ethical considerations remain. This review highlights the transformative potential of multi-omics in AML, emphasizing recent advancements in technology, biomarker discovery, and therapeutic innovation. By bridging the gap between molecular insights and clinical practice, multi-omics integration promises to redefine AML management, paving the way for precision oncology and improved patient outcomes.

Humans↗
PubMed1984

Antiarrhythmic treatment: an overview.

Atrial and ventricular arrhythmias cause significant morbidity and mortality. Abnormalities of impulse generation, e.g., abnormal automaticity or triggered activity, or abnormalities of impulse conduction, e.g., atrioventricular block or reentry, are the prime mechanisms of atrial or ventricular arrhythmias. The ventricular arrhythmias are of special interest because they are a key element in sudden cardiac death, the number 1 public health problem in the U.S. Electrocardiographic recording or provocative testing, e.g., exercise or programmed ventricular stimulation, are used to detect and classify ventricular arrhythmias. Drugs with different mechanisms of action are being rapidly developed to combat cardiac arrhythmias. Ventricular arrhythmias can be defined as benign, potentially malignant or malignant. Benign ventricular arrhythmias require no drug treatment; potentially malignant arrhythmias are subject to drug prophylaxis; and the malignant ventricular arrhythmias require aggressive therapy with drugs, surgery or electronic devices. The management of the malignant ventricular arrhythmias should be evaluated by 1 of 2 programmatic approaches: electrophysiologic or Holter/exercise. Both are complex, costly and inconvenient, but both are excellent for identifying effective treatment for malignant ventricular arrhythmias.

Anti-Arrhythmia Agents↗
PubMed1984

Optimization of detectors for modern liquid chromatography.

The development of modern liquid chromatographic methods depends strongly on the development of suitable measuring systems for the separated compounds. This is the case as generally an on-line coupling of separation and detection is preferred because of ease of operation, reliability and more efficient data handling. Unfortunately, the best conditions for the separation are often not optimal from the detection point of view. Conflicts arise in various respects and compromises have to be made. Depending on the complexity, cost and performance of each, either the chromatographic separation, or the detection process, has to be adapted, the one to the other. A number of contemporary developments in the techniques of liquid chromatography tend to sharpen these conflicts. Further reduction in particle size, reduction of the column diameter, introduction of multicolumn operation and the exploration of open tubular liquid chromatography can be mentioned in this respect. From this point of view a broad discussion of the role of detection techniques in the development and performance of liquid chromatographic analytical procedures is given.

Journal Article↗
PubMed1995

Two miniature monitors for long-term ambulatory studies.

Two very low-power monitors are described. One typically limb-worn to record the level of physical activity of a person; the other, used with surface electrodes, to record three parameters of an EMG signal. The monitoring period can extend to days with a very accurate 'time of event' log. A novel method has been devised to double the resolution of the data gathered. A PC is used to store and process the collected data, which can be displayed or printed as one-, or four-channel, time-related histogram. The gathered data can also be analysed for trends and other statistical analysis. The hardware is relatively simple and made from low-cost components. Neither monitor uses a microprocessor for data gathering. The system is very easy to use requiring minimal operator training. Where 'no-frills' ambulatory monitoring is called for, the systems presented would compare very favourably with other commercially available monitors, either on cost, complexity of setting up, or on weight.

Circadian Rhythm↗
PubMed2005

Diagnostic ability of B-type natriuretic peptide and impedance cardiography: testing to identify left ventricular dysfunction in hypertensive patients.

BACKGROUND: Patients with hypertension are at high risk for the development of left ventricular dysfunction (LVD). Echocardiography is considered to be the gold standard for diagnosis of LVD; but its cost, complexity, and availability prevents its use for frequent evaluation. Brain natriuretic peptide (BNP) and N-terminal BNP (NT-BNP) can identify heart failure in dyspneic patients. Impedance cardiography (ICG) is a noninvasive method of measuring hemodynamic and electromechanical timing parameters. The objective of this study was to determine the ability of BNP, NT-BNP, and ICG to detect the presence of LVD in patients with hypertension. METHODS: A convenience sample of subjects undergoing echocardiography who had a history of hypertension or current systolic blood pressure >/=140 mm Hg were enrolled and retrospectively evaluated. Patients with known LVD were excluded. Diagnosis of LVD was determined by the presence of systolic or diastolic dysfunction, valvular or wall motion abnormalities, or left ventricular hypertrophy. RESULTS: A total of 193 subjects were enrolled: 189 men and four women, age 68.8 +/- 11.7 years. Multivariate regression analysis of history and symptoms, BNP, and ICG parameters identified significant predictor variables for LVD including cardiac index (P = .005), left cardiac work index (P = .008), BNP (P = .017), arrhythmia (P = .023), angina (P = .034), and systemic vascular resistance (P = .048). Receiver operating characteristic (ROC) analysis determined the area under the ROC curve (AUC) of BNP (0.60), NT-BNP (0.67), ICG velocity index (0.66), composite ICG (0.66), ICG combined with BNP (0.70), and ICG combined with NT-BNP (0.73). CONCLUSIONS: In this high-risk hypertensive population, BNP, NT-BNP, and ICG were useful to identify the presence of LVD. The use of ICG with natriuretic peptide testing may improve the ability to detect LVD.

Aged↗
PubMed2005

Estimating live birth rates after ovulation induction in polycystic ovary syndrome: sample size calculations for the pregnancy in polycystic ovary syndrome trial.

Polycystic ovary syndrome (PCOS) affects approximately 5% of the female population, and is a leading cause of infertility, primarily secondary to anovulation. Clomiphene citrate has been standard therapy for ovulation induction in patients seeking pregnancy, but recent evidence suggests that insulin sensitizing agents such as metformin may also be effective. The National Institute of Child Health and Human Development's Reproductive Medicine Network has begun a randomized, double-blind trial of clomiphene vs. metformin vs. clomiphene plus metformin for the induction of ovulation in patients with PCOS seeking pregnancy, with live birth rate as the primary outcome. Because the available literature was largely limited to surrogate outcomes such as ovulation and pregnancy rates, we created a Markov model to derive estimates of likely live birth rates in each arm. Using these estimates, we then constructed an algorithm that allowed only two formal comparisons between the three arms. First, we assumed that combination therapy would have to be superior to the next best single-agent therapy in order to be preferred, because of complexity, costs, increased side effects, etc. If combination therapy is not superior to the next best single agent, then the only other comparison of interest is between the two single agent therapies. Because the third possible comparison, between the best and worst of the three therapies, is not clinically relevant, it can be eliminated from formal statistical consideration, with subsequent reduction in sample size. Based on the opinion of the Network Steering Committee that a 15% absolute difference in live birth rates would be clinically relevant, our methodology resulted in a sample size of 226 per arm, or a total of 678 subjects. The PPCOS trial should definitively answer the question of the relative efficacy of metformin, clomiphene, and combination therapy in the treatment of infertile women with PCOS.

Adolescent↗
PubMed2004

Cardiac resynchronization therapy optimization by finger plethysmography.

OBJECTIVES: We tested a simple noninvasive method for cardiac resynchronization therapy (CRT) optimization using standard finger photoplethysmography (FPPG). BACKGROUND: CRT can increase left ventricular cardiac output in patients with heart failure and ventricular conduction delay. Optimal therapy delivery depends on an appropriate AV delay. Multiple invasive and noninvasive methods have been attempted to identify patients and the best AV delay for CRT, but all suffer from a combination of high patient risk, cost, complexity, and low reproducibility. METHODS: FPPG and invasive aortic pressure data were simultaneously collected from 57 heart failure patients during intrinsic rhythm alternating with very brief periods of pacing at 4 to 5 AV delays. After correcting data for artifacts, the median percentage responses for each AV delay were classified as positive, negative, or neutral compared to baseline (Wilcoxon rank test). RESULTS: FPPG correctly identified positive aortic pulse pressure responses with 71% sensitivity (95% CI: 60-80%) and 90% specificity (95% CI: 84-94%) and negative aortic pulse pressure responses with 57% sensitivity (95% CI: 44-69%) and 96% specificity (95% CI: 91-98%). The magnitude of FPPG changes were strongly correlated with positive aortic pulse pressure changes (R(2) = 0.73, P < .0001) but less well correlated with negative aortic pulse pressure changes (R(2) = 0.43, P < .0001). FPPG selected 78% of the patients having positive aortic pulse pressure changes to CRT and identified the AV delay giving maximum aortic pulse pressure change in all selected patients. CONCLUSIONS: FPPG can provide a simple noninvasive method for identifying significant changes in aortic pulse pressure with high specificity, including identifying patients in whom aortic pulse pressure increases with CRT and the AV delay giving the maximum aortic pulse pressure.

Aorta↗
PubMed2005

An alternative method of anthropometry of anterior cruciate ligament through 3-D digital image reconstruction.

Accurate and flexible measurements of length, area, and volume are important in evaluation of the mechanical properties of soft tissue. Although a number of contact-based and non-contact techniques have been reported in the literature, due to a variety of reasons such as cost, complexity, and low accuracy, the research community has not adopted a standardized technique. In this paper, an alternative method of measuring the geometric parameters of cadaver anterior cruciate ligament (ACL) is presented. In this method, a 3-D scan of the ACL is constructed using a simple, commercially available, scanning system. The 3-D scan is then analyzed using the 3-D Doctor Software to extract important information regarding the length, cross-sectional area, and volume of the ACL. The accuracy and repeatability of measurements obtained by this method are acceptable and comparable to existing non-contact methods. The limitation of the method is that surface concavities cannot be detected. However, the non-contact optical method, described here, has inherent advantages over the existing methods: (1) it is inexpensive; (2) it allows the determination of area at any distance along the length of the tissue of interest; (3) all relevant information including minimum area is extracted from one single application of the method; (4) the volume can be calculated with a simple additional step of length measurement although, for accurate results, condylar blockage must be minimized by coring the ACL out. The entire process of scanning takes less than 30 min. This technique has the potential to become a standard method in anthropometry of soft tissue.

Anterior Cruciate Ligament↗
PubMed2005

The comparison of different feed forward neural network architectures for ECG signal diagnosis.

The electrocardiograms (ECGs) record the electrical activity of the heart and are used to diagnose many heart disorders. This paper proposes a two-stage feed forward neural network for ECG signal classification. The research is aimed at the design of an intelligent ECG diagnosis tool that can recognise heart abnormalities while reducing the complexity, cost, and response time of the system. A number of neural network architectures are designed and compared for their ability to classify six different heart conditions. Two network architectures based on one stage and two stage feed forward neural networks are chosen for this investigation. The training and testing ECG signals are obtained from MIT-BIH database. The network inputs are comprised of 12 ECG features and 13 compressed components of each heart beat signal. The performance of the different modules as well as the efficiency of the whole system is presented. Among different architectures, a proposed multi-stage network named NET_BST possesses the highest recognition rate of around 93%. Therefore, this network proves to be a suitable candidate in ECG signal diagnosis systems.

Algorithms↗
PubMed2026

Innovative advances and clinical applications of cell-free DNA methylation detection technologies.

Advances in DNA methylation detection technologies have promoted disease-related cell-free DNA (cfDNA) analysis. CfDNA methylation profiling has the potential to serve as a promising clinical tool for early disease diagnosis. However, current detection technologies suffer from high costs, complex operational procedures, and insufficient sensitivity for low-input samples. Moreover, the definitive validation of its clinical value still awaits robust evidence from high-quality confirmatory studies. Therefore, this review begins by mapping the historical evolution of cfDNA methylation, followed by a comparison of the traditional approaches and recent breakthroughs in cfDNA methylation analysis. Specifically, this review systematically examines the two major strategies: the ones based on bisulfite-dependent DNA modification and the bisulfite-free methods, including the techniques for whole-genome methylation profiling and methods targeting specific genomic regions. Additionally, to evaluate the clinical application potential of these methods, this review comprehensively describes the details of these technologies, such as sample input requirements and sensing accuracy in detecting clinical samples. The future development of cfDNA methylation detection will focus on clinical translation, integrating technical innovations with the demands for efficient clinical diagnosis. We believe this review will help researchers select methods tailored to sample availability and clinical applicability.

Humans↗
PubMed2003

Constructing a database of individual clinical trials for longitudinal analysis.

Individual patient data are often required to evaluate how patient-specific factors modify treatment effects. We describe our experience combining individual patient data from 1946 subjects in 11 randomized controlled trials evaluating the effect of angiotensin-enzyme converting (ACE) inhibitors for treating nondiabetic renal disease. We sought to confirm the results of our meta-analysis of group data on the efficacy of ACE inhibitors in slowing the progression of renal disease, as well as to determine whether any study or patient characteristics modified the beneficial effects of treatment. In particular, we wanted to find out if the mechanism of action of ACE inhibitors could be explained by adjusting for follow-up blood pressure and urine protein. Each trial site sent a database of multiple files and multiple records per patient containing longitudinal data of demographic, clinical, and medication variables to the data coordinating center. The databases were constructed in several different languages using different software packages with unique file formats and variable names. Over 4 years, we converted the data into a standardized database of more than 60,000 records. We overcame a variety of problems including inconsistent protocols for measurement of key variables; varying definitions of the baseline time; varying follow-up times and intervals; differing medication-reporting protocols; missing variables; incomplete, missing, and implausible data values; and concealment of key data in text fields. We discovered that it was easier and more informative to request computerized data files and merge them ourselves than to ask the investigators to abstract partial data from their files. Although combining longitudinal data from different trials based on different protocols in different languages is complex, costly, and time-intensive, analyses based on individual patient data are extremely informative. Funding agencies must be encouraged to provide support to collaborative groups combining databases.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1997

DNA diagnosis for the practicing obstetrician.

Laboratory advances in molecular genetics have resulted in numerous clinical applications for DNA analysis. Currently, because of cost, complexity, and resource limitations, DNA analysis is not used routinely for prenatal screening, but rather is targeted towards families at risk for an inherited condition. This article discusses the types of DNA analyses that are currently performed, the possible tissue sources of DNA for prenatal diagnosis, and the indications for DNA testing in obstetric practice. Internet addresses for the most up-to-date genetic information on a specific condition are given in this article.

Chromosome Mapping↗
PubMed1997

Automating and improving the data quality of a nursing department quality management program at a university hospital.

BACKGROUND: The development and implementation of a relational database program for nursing quality management at a university hospital was stimulated by a lack of consistent data management and analysis tools in the existing noncomputerized program. PROGRAM DEVELOPMENT AND IMPLEMENTATION: An initial software prototype implemented in the critical care service included data collection instruments for five areas: medication errors, patient falls, returns to an intensive care unit within 48 hours, hospital-acquired skin breakdown, and unplanned extubations. Access to the database was limited and paper reports only were disseminated on a scheduled basis. In a second phase, the database is being deployed throughout the nursing department using a local area network. Nurse managers will enter and interact with the quality database online and have access to graphics, reports, and action plan development. POSSIBLE ERRORS: A wide range of potential errors influences decisions on how to collect, store, retrieve, and process quality management data. Each type of error affects the nurse manager's ability to identify significant patterns or trends that are amenable to intervention. There is no right way of constructing and implementing a quality improvement database; only an optimum balance between cost, complexity, and efficacy. SUMMARY AND CONCLUSIONS: Initial feedback from end uses has been positive. A three-year experience with a personal computer database suggests that the personal computer-based information technology is appropriate for small to medium applications and can support departmentwide CQI efforts. A case scenario using simulated data is included to illustrate the use of computerized reports in assessing and taking action on an increase in falls.

Accidental Falls↗
PubMed2006

Sputum processing methods to improve the sensitivity of smear microscopy for tuberculosis: a systematic review.

In low-income and middle-income countries, direct (unconcentrated) sputum smear microscopy is the primary method for diagnosing pulmonary tuberculosis. The method is fast, inexpensive, and specific for Mycobacterium tuberculosis in high incidence areas. The main limitations of direct microscopy are its relatively low sensitivity, especially in individuals co-infected with HIV, and variable quality of the test in programme conditions. Thus, there is a need to identify methods to improve the sensitivity of microscopy. Physical and chemical sputum processing methods, including centrifugation, sedimentation, and bleach, have been studied and found to show promise. We did a systematic review to assess the ability of different processing methods to improve the sensitivity of microscopy. By searching many sources, we identified 83 studies. Overall, by comparison with direct smears, the results suggested that centrifugation with any of several chemical methods (including bleach) is more sensitive, that overnight sedimentation preceded by chemical processing is more sensitive, and that specificity is similar. There were insufficient data to determine the value of sputum processing methods in patients with HIV infection. Operational studies are needed to determine whether the increased sensitivity provided by processing methods is sufficient to offset their increased cost, complexity, and potential biohazards, and to examine their feasibility.

Bacteriological Techniques↗
PubMed2005

Electrochemical alkaline Fe(VI) water purification and remediation.

Fe(VI) is an unusual and strongly oxidizing form of iron, which provides a potentially less hazardous water-purifying agent than chlorine. A novel on-line electrochemical Fe(VI) water purification methodology is introduced. Fe(VI) addition had been a barrier to its effective use in water remediation, because solid Fe(VI) salts require complex (costly) syntheses steps and solutions of Fe(VI) decompose. Online electrochemical Fe(VI) water purification avoids these limitations, in which Fe(VI) is directly prepared in solution from an iron anode as the FeO42- ion, and is added to the contaminant stream. Added FeO42- decomposes, by oxidizing a wide range of water contaminants including sulfides (demonstrated in this study) and other sulfur-containing compounds, cyanides (demonstrated in this study), arsenic (demonstrated in this study), ammonia and other nitrogen-containing compounds (previously demonstrated), a wide range of organics (phenol demonstrated in this study), algae, and viruses (each previously demonstrated).

Electrochemistry↗
PubMed2002

A review of diagnostic techniques in the differential diagnosis of epileptic and nonepileptic seizures.

The diagnosis of psychogenic nonepileptic seizures (PNES) is complex. Long-term electroencephalogram monitoring with video recording (video EEG) is the most common method of differential diagnosis of epilepsy and PNES. However, video EEG is complex, costly, and unavailable in some areas. Thus, alternative diagnostic techniques have been studied in the search for a diagnostic method that is as accurate as video EEG, but more cost effective, convenient, and readily available. This paper reviews the literature regarding possible diagnostic alternatives and organizes findings into 7 areas of study: demographic and medical history variables, seizure semiology, provocative testing, prolactin levels, single photon emission computed tomography, psychological testing, and neuropsychological testing. For each area, the literature is summarized, and conclusions about the accuracy of the technique as a diagnostic tool are drawn. Overall, it appears unlikely that any of the reviewed alternative techniques will replace video EEG monitoring; rather they may be more successful as complementary diagnostic tools. An important focus for further investigations involves combinations of diagnostic techniques for the differential diagnosis of epilepsy and PNES.

Diagnosis, Differential↗