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At least 865 records · Page 48Linked to original sources
PubMedDate not supplied

[Real-time PCR: approaches to data analysis (a review)].

The registration of the accumulation of polymerase chain reaction (PCR) products in the course of amplification (real-time PCR) requires specific equipment, i.e., detecting amplifiers capable of recording the level of fluorescence in the reaction tube during amplicon formation. By the time the reaction is completed, researchers obtain DNA accumulation graphs. The review discusses the most promising algorithms of analysis of real-time PCR curves and possible errors, whether caused by the software used or the operators' mistakes. The data included will assist researchers in understanding the features of the method to obtain more reliable results.

Algorithms↗
PubMed1989

Kinetic assay of cytotoxic T lymphocyte clones. I. Methodology and data analysis.

A kinetic assay for cytotoxic T lymphocyte (CTL) clones expanded briefly in culture is described. The Hill equation for allosteric kinetics is used to fit curves to dose-response data. In this assay, K0--the target cell concentration required for half-maximal velocity of killing--is determined for clones generated from a population's most frequent CTL precursors. Because each clone's K0 is a constant under given conditions and a description of relative cytolytic efficiency, K0 values can be used to compare the clonal composition of disparate or dynamic populations. The parameter n is the target concentration exponent in the Hill equation and the slope of the line in the Hill plot. This parameter further specifies the shape of a clone's dose response curve, describing a clone's responsiveness to changes in target cell concentration. Because the assay is designed for small, undetermined effector cell concentrations, maximum velocities are not compared. The method described herein requires minimal supplies, equipment, and biological materials.

Animals↗
PubMed2006

Data analysis of alternative splicing microarrays.

The importance of alternative splicing in drug and biomarker discovery is best understood through several example genes. For most genes, the identification, detection and particularly quantification of isoforms in different tissues and conditions remain to be carried out. As a result, the focus in drug and biomarker development is increasingly on high-throughput studies of alternative splicing. Initial strategies for the parallel analysis of alternative splicing by microarrays have been recently published. The design specificities and goals of alternative splicing microarrays, in terms of identification and quantification of multiple mRNAs from one gene, are promoting the development of novel methods of analysis.

Algorithms↗
PubMed2005

Women's sexual concerns: data analysis from a help-line.

PURPOSE: To report female sexual problems and concerns, as presented by women calling a help-line, and to evaluate women's help-seeking behavior regarding sexual matters. MATERIALS AND METHODS: The study included all telephone calls from women who called for sexual concerns to a help-line dedicated to sexual problems during a 5-year period. During the call, the counselor addresses demographic characteristics of the caller, the sexual problem reported, their sexual function, any previous doctor contacts, coexisting physical and mental health problems, couple's relationship, and lifestyle factors that may influence sexual function. Data processing employed descriptive statistics and logistic regression analysis in order to detect possible associations between categorical variables. RESULTS: Of a total of 3,523 calls made by women, 2,287 full forms were analyzed, reflecting a response rate of 64.9%. Most women (46.6%) called for problems encountered by their partners, 45.1% called for their own sexual problems, while 5.9% were calling for their children. Only 34.3% of them had already consulted a doctor. The most frequently reported difficulties were achieving orgasm (25.6%), reduced sexual desire (16.9%), and pain during intercourse (6.1%). Women in the 40-49 age group had the higher odds ratios for the sexual problems reported (reduced sexual desire: odds ratio [OR] 5.0; difficulties achieving orgasm: OR 6.3; pain during intercourse: OR 5.8). Both married and single women had high risk of experiencing low levels of sexual desire (40% and 30%, respectively). CONCLUSIONS: Women's sexual concerns are not devoted to their sexual problems, but also their partner's and children's problems. Most frequently reported sexual problems are difficulties in reaching orgasm and reduced sexual desire. However, women are reluctant to seek medical advice on their sexual concerns. There is a need for general practitioners and family doctors to become aware of the possibility of a sexual problem and to be trained on how to manage this at a primary care level.

Adult↗
PubMed1991

Peak assignment in automatic data analysis.

Linear prediction algorithms are able to identify peaks in an NMR spectrum, but are not able to assign these peaks to components anticipated in the spectrum. We have developed an artificial-intelligence protocol which uses the output parameter list from an LPSVD algorithm, and automatically assigns the peaks on the basis of an anticipated list of components. To overcome the influence of experimental conditions on the absolute values of frequency, integrated area, and linewidth, the assignment routine performs an internal scaling of the data by comparing all possible pairs of peaks in the spectrum. Completely automated analysis of large numbers of in vivo FIDs is now possible.

Adenosine Triphosphate↗
PubMed1995

Methodology of spontaneous baroreflex relationship assessed by surrogate data analysis.

We tested the hypothesis that the spontaneous beat-by-beat interactions of systolic blood pressure (SBP) and R-R interval reflected true baroreflex events rather than chance interactions. Original data sets of 1,024 heartbeats obtained in seated rest from six healthy subjects [R-R interval = 953 +/- 94 (+/- SE) ms] were compared with isospectral [generated by a windowed (inverse) Fourier transform with phase randomization] and isodistribution (data points randomly shuffled) surrogate data sets. The isospectral data set was used to test for random phase relationships, and the isodistribution data set was used for effects of white noise between SBP and R-R interval. Spontaneous baroreflex sequences were defined as three or more beats in which SBP and the R-R interval of the same (lag 0), next (lag 1), or next following (lag 2) beat changed in the same direction. The total number of baroreflex sequences in the original data was significantly greater than the surrogates (P < 0.001). In the original data, there were significantly (P < 0.001) more lag 0 than lag 1 or lag 2 baroreflex sequences. Therefore, these results indicated that spontaneous baroreflex sequences represented physiological rather than chance interactions and that baroreflex responses can occur within the same beat.

Adult↗
PubMed1984

Experiences in the application of NONMEM to pharmacokinetic data analysis.

Ethical issues arising from the use of patients in medical research have stimulated pharmacokinetic research in population kinetics, which requires only a few concentration samples of each individual. Using historical maprotiline data, the new approach of population kinetics was investigated and compared to individually estimated kinetics. Two different population kinetic methods were applied. The naive approach, a quick and dirty method, was compared to the nonlinear mixed-effects method, which was applied by the NONMEM package. Based on the results we obtained from actual maprotiline data as well as from simulated data, NONMEM is a reasonable tool for the estimation of population pharmacokinetic parameters. The main advantage of NONMEM over the naive approach lies in the possibility of obtaining standard deviations of random effects related to the variability between subjects.

Computers↗
PubMed1991

On the choice of times for data analysis in group sequential clinical trials.

Planned interim analysis of randomized clinical trials has been implemented for over a decade. While the initial proposal advocated analyzing after equal numbers of patients were evaluated, a later modification by Lan and DeMets (1983, Biometrika 70, 659-663) allowed for more flexible boundaries. Rather than fixing the times of analysis at equal numbers of patients, they fixed the rate at which overall alpha was used up according to a use function alpha * (t) on t in with alpha * (0) = 0 and alpha * (1) = alpha. Here we consider how flexible Lan and DeMets' procedure is. We show that the choice of alpha * (t) for a particular trial affects the permissible analysis times if other desirable properties of the sequence of nominal significance levels are to hold. To overcome the difficulties posed by patterns of late analysis, piecewise linear convex use functions are proposed.

Biometry↗
PubMed1989

Semen analysis data from fresh and cryopreserved donor ejaculates: comparison of cryoprotectants and pregnancy rates.

Patients (155) were selected at random for fresh or cryopreserved semen and inseminated on the predicted day of ovulation. Semen analysis was performed using a microcomputerized multiple-exposure photography system. Frozen semen was used with either glycerol or TEST-yolk (TEST-buffered 20% egg yolk with 10% glycerol) as the cryoprotectant. Cryopreservation resulted in significant decreases in all semen parameters measured. Of these, velocity appeared to be the least effected. TEST-yolk provided significantly more protection against a reduction in velocity compared with glycerol. A total of 18, 17, and 27 patients conceived using fresh, glycerol, or TEST-yolk-preserved semen, respectively. For these same groups, a cumulative pregnancy rate of 52.9%, 27.1%, and 68.5%, respectively, was observed (not significant). The total number of motile sperm per insemination used for fresh artificial inseminations resulting in conception (132.4 X 10(6] was significantly greater than the number used for successful glycerol- and TEST-yolk-preserved semen (approximately 24 X 10(6]. These results demonstrate that although the number of motile sperm of cryopreserved ejaculates are dramatically reduced compared with the fresh counterparts, if a minimum criteria for ejaculate quality is established, the use of cryopreserved semen can offer a viable, effective, and relatively safe alternative to artificial insemination by donor with fresh semen.

Cell Survival↗
PubMedDate not supplied

Know your APCs: data analysis made simple.

You've adapted processes to the APC system, but do you really understand the financial impact of APCs on your organization? The author shows you how to analyze your billing data to assess the impact of APCs on your facility's bottom line.

Ambulatory Care↗
PubMed1999

Telemetry for cardiovascular monitoring in a pharmacological study: new approaches to data analysis.

Radio-telemetry systems offer the ability to measure blood pressure and heart rate in experimental models of hypertension without the stress artifacts induced by some other methods. We therefore aimed to develop improved, nonparametric regression methods for radio-telemetry data and to use these to assess the effects of pharmacological interventions on cardiac and vascular hypertrophy in the stroke-prone spontaneously hypertensive rat. One control group and 5 groups treated either with losartan (alone or in combination with NG-nitro-L-arginine methyl ester [ L-NAME]), perindopril (also alone or in combination with L-NAME), or hydralazine plus hydrochlorothiazide were monitored for 4 weeks. Cardiac hypertrophy was assessed by the left ventricle plus septum weight to body weight ratio and vascular hypertrophy by flow-cytometry analysis of vascular smooth muscle cell polyploidy. Hemodynamic series were split into trend and cyclic components by the seasonal and trend decomposition procedure based on Loess and compared between groups by Loess regression modeling. Systolic and diastolic blood pressures were reduced systematically by losartan and perindopril (P<10(-10)) but to a lesser extent by hydralazine plus hydrochlorothiazide (P<10(-8)), and diurnal variation was reduced in the latter group (P<10(-6)). L-NAME significantly reduced the hypotensive effect only of losartan. Vascular and cardiac hypertrophy were significantly attenuated with losartan or perindopril, but were unchanged with other treatments. The new analysis proposed here identifies differential effects on trends and cyclic variation and associations with regression of end-organ damage for losartan and perindopril compared with hydralazine plus hydrochlorothiazide. The method offers a powerful tool for detailed investigation of radio-telemetry data.

Animals↗
PubMed2006

Gastric cancer treated in 1991 in Japan: data analysis of nationwide registry.

The Japanese Gastric Cancer Association Registration Committee reported the treatment results and causes of death of patients with primary gastric cancer treated in 1991 at the leading hospitals in Japan. Data of 8851 patients with primary gastric cancer were collected from 113 hospitals, and data of 7935 patients with gastric resection were finally analyzed. The lost-to-follow-up rate was 6.9%; the direct death rate was 1.0%. The cumulative 5-year survival rate (5YSR) of all the patients was 68.2%; 89.9% for Stage I, 69.1% for Stage II, 43.5% for Stage III, and 9.9% for Stage IV. Characteristic findings of the analyzed data were (1) high proportion of early-stage cancer, (2) high resection rate, (3) low mortality rate, (4) low incidence of upper-third cancer, (5) poor treatment results in cases with scirrhous cancer, infiltrating growth, and marked lymphatic or venous invasion, and (6) predominance of systematic (D2) and extended lymphadenectomies possibly resulting in reducing local recurrence and improving survivals.

Adult↗
PubMed2000

[The individual characteristics of the cytoarchitectonics of the human motor cortex (based on computer analysis data)].

Age and individual peculiarities of cytoarchitecture of layer III field 4p, periods of intensive and slow growth of the area of profile fields (APF) of pyramid neurons were established by method of computer analysis of histological preparations of human motor cortex from birth up to 20 yrs. It was shown that the greatest changes of APF of pyramid neurons including their individual parameters occur in field 4 of motor cortex during first three years.

Adolescent↗