SEARCH · PubMed Health

Results for “parameter identification”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 559 records · Page 31Linked to original sources

PubMed1978

[Analytical study and processing of information from a primary intervention report].

Analytical study of treatment of information from a primary intervention by the S.A.M.U. were brought about with the aim of performing a "statistical" study of enumeration of the various possibilities, using three "standard" programmes. After exploitation of the statistical data, the card index is stocked on conventional magnetic tape and verified by different parameters permitting its identification. In addition, the concatenation of different card indices is easy to obtain, which makes it possible to carry out research into all existing file cards regardless of the month or year.

Electronic Data Processing↗

PubMed1987

[Advances and perspectives in American cutaneous leishmaniasis].

The advances and perspectives in American (mucocutaneous) leishmaniasis are presented under the following topics: 1. Epidemiology in Latin America, particularly in Brazil. 2. Parameters for taxonomic identification of species and subspecies of the genus leishmania, which belong to L. mexicana and L. braziliensis complexes: biologic behaviour in hamster, in culture, in animal reservoir, clinical aspects, vectors, electronic microscopy, electrophoretic mobility of isoenzymes, radiorespirometry, DNA characterization, monoclonal antibodies, other immunological aspects and genetics. 3. Diagnosis by intradermal test, indirect immunofluorescence, ELISA, culture and animal inoculation. 4. Therapeutics and prevention by vaccination.

Animals↗

PubMed1986

[Mathematical model for estimating the ratio of cells having passed the different number of divisions in the culture].

Different versions of the stochastic expansion of the continuous determined linear model proposed formerly for evaluation of the ratio of cells having passed the different number of divisions in the culture were worked out and theoretically based. The influence of approximation precision of the continuous model by its discrete analogues on the adequacy of the process under study was examined. The problem of simultaneous identification of unknown parameters and the model's primary conditions was solved. The proposed methods for construction of the stochastic models for evaluation of the ratio of cells having passed the different number of divisions in the culture make it possible not only to determine analytically the correlation of metaphases of the first, second, third and following divisions at definite times of fixation and under different conditions, but also to evaluate reliability of the results obtained.

Cell Count↗

PubMed1984

[The operational aspect of thought in psychopathology. Analytic factors and classification of technics].

The identification of the parameters of analysis allowing a strictly definite assessment of the results of qualitative techniques of examination is essential for increasing the reliability and validity of these methods. The author presents an extensive classification of the analytic factors reflecting the operational side of thinking. The analysis is made on the basis of such parameters as abstraction standardization and adequacy. Principles have been elaborated for a discrete evaluation of the abstraction levels. The evaluation is fit for standardization and does not depend on the method employed. A classification of the verbal techniques for studying the thinking is offered which will take into account the nature of the task, "the range of sensitivity", validity and reliability. The specific characteristics of concrete techniques are outlined in detail which will contribute to their more adequate use in pathopsychological studies.

Humans↗

PubMed1984

[Radionuclide study of reticuloendothelial system function].

The authors propose a new method for the interpretation of the measurement data obtained during radionuclide investigations of the function of the reticuloendothelial system (RES). This method is upon the concept of a considerable effect of the blood opsonizing factor on the transport of i.v. injected radioactive colloid in the body. A non-linear compartmental model was developed that describes the binding of colloid particles with opsonins in the vascular bed followed by absorption of the particles of the colloid-opsonin complex by RES cells. The identification of the parameters of the non-linear model by the results of dynamic scintigraphy of the heart and liver makes it possible to explain some phenomena in the measurement data and to assess the relative amount of opsonins in the blood and RES phagocytic activity as a whole and its constituents. It was shown in particular in the studies on patients with hepatocirrhosis that the amount of opsonins in the blood remains almost the same as compared to the normal one whereas the phagocytic activity of RES on the whole, hepatic stellate cells and RES extrahepatic cells decreases significantly.

Colloids↗

PubMedDate not supplied

Osmotic effects on neutrophil segmentation. An in vitro phenomenon.

Segementation of the nucleus is an important morphologic characteristic of mature neutrophils and is a useful parameter for their identification in various body fluids. From our studies, we have demonstrated that when mature neutrophils are placed in low specific gravity urine, cellular enlargement and a loss of nuclear segmentation occur, resulting in inaccurate identification. Both cytotechnologists and investigators involved in neutrophil research should be aware of the effects of tonicity on morphologic characteristics.

Cell Nucleus↗

PubMed1982

Forensic applications of scanning electron microscopy/energy dispersive X-ray analyser in Hong Kong.

Scanning Electron Microscopy - Energy Dispersive X-Ray Analysis (SEM/EDX) has been applied in casework for more than a year in the Forensic Division, Government Laboratory of Hong Kong. The types of samples being analysed are summarised and three cases of scientific interest are described. The first case applies SEM/EDX to characterize microscopic gold particles recovered from clothing of suspects involved in goldsmith robberies. Both elemental and morphological results obtained were used as supporting evidence. The second case describes the three types of beaded ends on fibres found in a single cloth sample. These beaded ends are different in shape and surface features and can be used as an additional parameter in fibre identification. The final case shows the application of vacuum evaporation of graphite on a document sample to reveal the area of paper which has been skillfully mechanically erased. Both the image intensity and the composition of the ink are used to differentiate between original and altered characters on the document.

Clothing↗

PubMed1994

[Controversies and progress in the diagnosis and treatment of benign prostatic hypertrophy. Personal experience].

Historically, non surgical procedures awakened little interest among urologists because surgery represented a definite solution with acceptable morbidity and mortality rates. Currently, the diagnosis and management of BPH is pointed towards a greater understanding of those prostate conditions with a trend to obstruction, using more refined methods to assess the severity of the obstruction, identification of predictive parameters of the therapeutical response, and evaluation of the various treatment alternatives based on safety and cost-efficiency parameters.

Humans↗

PubMed1994

[Plague in Zaire].

Two endemic foci of plague have been discovered in Zaïre, the first in the Ituri in 1928, the other in North-Kivu in 1938. They are situated in the region of the great East-African Rift and are adjacent to the Ugandan focus, identified in 1877. A strict surveillance of these endemic foci makes it possible to state that, between 1928 and 1959, 632 cases of plague have been diagnosed in the Ituri, or 20 a year, and 190 in the N-Kivu, or 8 a year. Since then several flare ups have been notified. This situation is very remote from the "black death" concept. Yersinia pestis presents, besides its bipolar staining, many other characteristics such as the indispensable presence of iron to produce virulence, or the fermentation of glycerine and reduction of nitrates as parameters for the identification of 3 biovars, corresponding with a specific geographic distribution: antiqua, medievalis, orientalis or maritima. The antigenic structure has been discussed and also the role of plasmids. Plague is a disease of rats, a variegated gathering of rodents with different degrees of tolerance and sensitiveness to Y.pestis, living in a frail equilibrium. The multimammate houserat was in the Ituri the principal agent until the black rat Rattus rattus invaded the region and a new balance came into being. The frequent changes in taxonomy of Mastomys caused uncertainties. The transmission is due to fleas subject to a blocking of their ventriculum by Y.pestis. Fleas play an active part in the process. Man is only a casual intruder. The pathogenicity is related to its invasiveness and its intracellular localization in macrophages and other R.E. cells, in which Y.pestis can survive. The bubo is characteristic of the disease. In Zaïre a septicaemic tendency has been observed, with a possible involvement of the C.N.S. and of the lungs. The latter may produce among the surrounding relatives primary pneumonic plague. The clinical diagnosis ought to be confirmed by bacteriologic investigation of the puncture fluid of the bubo, the blood, and when necessary the C.S.F. or the sputum by culture and/or animal inoculation. The treatment became very efficient since the availability of sulfamides and later antibiotics: aminoglycosides, chloramphenicol, tetracyclines. A timely administration ensures practically recovery. As soon as Y.pestis was identified vaccination was put into practice and in the first place by killed germs (Haffkine's lymph) to day with formalized F1, for mass vaccination live attenuated strains were used: Tjiwidej (Otten), E.V. (Girard), K120 (Grasset).(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1994

Comparative evaluation of different methods to estimate urea distribution volume and generation rate.

Eight methods to estimate urea distribution volume and generation rate from blood urea samples measured in dialysis patients are reviewed. An analytical solution has been provided for a double-pool variable volume kinetic model to allow for faster and more accurate simulation and identification. The reliable parameter estimates provided by the double-pool kinetic model starting from seven samples, were assumed as references for the estimates obtained by the remaining methods. These include three kinetic models and four methods based on urea mass-balance. In particular, the estimation techniques differ in the number of compartments where urea is assumed distributed (double- and single-pool) or in the number of blood urea samples. Among the methods based on mass-balance, two techniques neglecting the weight loss or the urea generation during dialysis, were also analysed. The results obtained during hemofiltration sessions using three samples, usually available in clinical practice at the beginning and at the end of dialysis, demonstrate that a new method based on double-pool kinetics provides, on average, the most reliable estimates. Moreover, methods belonging to a single pool view and including both weight loss and urea generation during dialysis seem to underestimate by 1 divided by 2 liters the urea distribution volume. However, neglecting the weight loss or the urea generation can overcompensate this error, resulting in a significant overestimation of the distribution volume. Finally, it has been experimentally proved that the single-pool kinetic methods overestimate the urea production rate, while techniques based on mass balance provide more reliable values.

Adult↗

PubMed1993

[Bacterial endocarditis: microbiological diagnosis].

The microbiological laboratory can assist in diagnosis and therapy of bacterial endocarditis with the following parameters: cultivation and identification of the causative organism, sensitivity testing including assessment of the minimal bactericidal concentration (MBC) and testing of antibiotic combinations with checkerboard titrations and time-kill curves. Serum bactericidal titers, although controversial with respect to their utility in prognosing the clinical outcome, are regarded useful by some authorities but not by others. Antibiotic assays, mainly for aminoglycosides and vancomycin, serve to monitor antibiotic serum levels.

Anti-Bacterial Agents↗

PubMedDate not supplied

[Extracorporeal membrane oxygenation (ECMO) in the newborn infant and the child with intractable respiratory failure].

Extracorporeal membrane oxygenation (ECMO) has become a nearly standard treatment for neonates with refractory hypoxemic respiratory failure due to various disease. Even though in the non-neonatal age the experience is less extensive, an increased widespread interest on the possible applications in children with severe life-threatening respiratory or cardiovascular insufficiency is well documented in the literature. General contraindications include presence of active bleeding, underlying lethal disease, congenital malformations, or severe brain damage. Whilst in the neonatal population common entry criteria have been widely accepted, the identification of precise parameters capable to predict mortality and thus indicating an ECMO support in older patients are still lacking. At present, nonetheless, more than 10.000 newborns and 1.000 children with severe respiratory insufficiency at high mortality risk have received an ECMO treatment, with a survival rate of more than 80% and 50%, respectively. The initial results of our ECMO program for both neonatal and pediatric patients with refractory respiratory failure are encouraging, both in terms of mortality and morbidity, and they will be briefly discussed.

Adolescent↗

PubMed1997

Serum transferrin receptor and its ratio to serum ferritin in the diagnosis of iron deficiency.

The objective of the study was to evaluate the diagnostic efficiency of laboratory tests, including serum transferrin receptor (TfR) measurements, in the diagnosis of iron depletion. The patient population consisted of 129 consecutive anemic patients at the University Hospital of Turku who were given a bone marrow examination. Of these patients, 48 had iron deficiency anemia (IDA), 64 anemia of chronic disease (ACD), and 17 patients had depleted iron stores and an infectious or an inflammatory condition (COMBI). Depletion of iron stores was defined as a complete absence of stainable iron in the bone marrow examination. Serum TfR concentrations were elevated in the vast majority of the IDA and COMBI patients, while in the ACD patients, the levels were within the reference limits reported earlier for healthy subjects. TfR measurement thus provided a reliable diagnosis of iron deficiency anemia (AUC(ROC) 0.98). Serum ferritin measurement also distinguished between IDA patients and ACD patients. However, the optimal decision limit for evaluation of ferritin measurements was considerably above the conventional lower reference limits, complicating the interpretation of this parameter. Calculation of the ratio TfR/log ferritin (TfR-F Index) is a way of combining TfR and ferritin results. This ratio provided an outstanding parameter for the identification of patients with depleted iron stores (AUC(ROC) 1.00). In anemic patients, TfR measurement is a valuable noninvasive tool for the diagnosis of iron depletion, and offers an attractive alternative to more conventional laboratory tests in the detection of depleted iron stores.

Adult↗

PubMedDate not supplied

Cisplatin nephrotoxicity: a multivariate analysis of potential predisposing factors.

STUDY OBJECTIVE: To evaluate the usefulness of biologic and pharmacologic parameters for early identification of cisplatin-induced renal dysfunction. DESIGN: Prospective evaluation of 62 consecutively admitted patients with cancer. SETTING: Cancer center. PATIENTS: Sixty-two consecutive patients with cancer (52 men, 10 women; mean age 61.9 yrs). INTERVENTIONS: Patients received cisplatin as a single short intravenous infusion every 3 weeks. One hundred twenty-one cycles were analyzed. The dosage in the first cycle ranged between 61 and 105 mg/m2 (mean 84 mg/m2). All patients received a standard hydration protocol. MEASUREMENTS AND MAIN RESULTS: Renal function was evaluated for each cycle before treatment (day 0) and before next cycle (day 21) based on the estimated creatinine clearance (Clcr). For each cycle, the weighted relative decrease (WD) of Clcr was calculated (WDClcr = 100 x [Clcr (day 0) - Clcr (day 21)]/[Clcr (day 0)](2). Total and ultrafilterable (UF) platinum were measured as a single-sample assay taken 16 hours after the end of cisplatin administration. The mean WDClcr was 0.07 min/100 ml (range -1.0 to +1.7 min/100 ml). The intensity of renal dysfunction evaluated by WDClcr was independent of cisplatin dosage, age, sex, body surface area, initial Clcr, and cycle number. Of interest, total and UF platinum concentrations were significantly correlated to WDClcr: the higher the platinum concentration, the greater the intensity of renal dysfunction. In stepwise regression analysis, UF platinum concentration was the only selected factor. The best prediction of UF platinum was obtained by stepwise regression including cisplatin dosage, initial Clcr, and cycle number (r=0.58, p<0.0001). CONCLUSION: We consider our results to be a first step toward a clinical strategy to identify patients at risk for renal dysfunction after cisplatin treatment.

Adult↗

PubMed1998

[Relationship between lipoprotein A, apolipoprotein A and their isoforms in parents and children].

OBJECTIVE: It has been observed that the apo(a) isoforms of low molecular weight predict the family history of premature ECV. Our objective was to study the relationship between the levels of Lp(a) and the isoforms of apo(a) in parents and children. PATIENTS AND METHODS: Twenty-four families, where at least one of the children had been diagnosed with familial or polygenic hypercholesterolemia and at least one of these children and one parent had Lp(a) > or = 30 mg/dl, were studied. They were classified according to whether Lp(a) was > or = < 30 mg/dl, with 44 and 38 subjects in each group, respectively. The total cholesterol, triglycerides, HDL and LDL, the Lp(a) and apo(a) isoforms were determined, as well as the relative concentration of the latter. RESULTS: The molecular weight average of the major isoform was lower in the group with high Lp(a) levels (592 +/- 38 vs 656 +/- 65 kD, p < 0.001). An inverse correlation between Lp(a) levels and the major isoform size was found (r = -0.522, p < 0.001). The correlation of the Lp(a) levels in the child with that of his or her "best fit" (the best fit parent was that whose level was closer to that of the child) was very significant (r = 0.61, p < 0.01), but lower than the corresponding paternal apo(a) isoform levels (r = 0.801, p < 0.01). The study of the apo(a) isoforms in parents and their children suggests not only that the isoform is inherited, but also its concentration. CONCLUSIONS: Subjects with small size apo(a) isoforms have higher Lp(a) levels. There is a better correlation between parents and children in the phenotypes of the apo(a) than in Lp(a) levels. The determination of these parameters allows the identification of a risk population.

Adolescent↗

PubMedDate not supplied

[Comparative analysis of isoenzyme patterns of beta-1,4 endoglucanase in species of Saccobolus genus (Ascobolaceae-Pezizales)].

Growth and beta-1, 4 endoglucanase production of six species of Saccobolus were determined. Twenty nine strains of thirteen geographical isolates were tested, using culture medium with crystalline cellulose as carbon source. All species showed good growth and enzyme activity. A high intraspecific homogeneity was observed as there were no differences in the variables measured within the strains of each geographical isolate and the only difference was between the two isolates of S. infestans. Each species had a characteristic electromorph, showing a variable number of isozymes with a maximum of 11 for S. seudodepauperatus and a minimum of 7 for S. platensis. These results support the usage of isoenzymatic patterns of beta-1, 4 endoglucanase and physiological parameters for the identification of species of Saccobolus as an aid to traditional taxonomy. This methodology is an additional tool to traditional taxonomy, based only on morphological characters.

Ascomycota↗

PubMed1998

Pseudorandom rotational stimuli of the vestibulo-ocular reflex in humans: normal values of the transfer function.

Pseudorandom binary rotatory stimulation is used to study the vestibulo-ocular reflex (VeOR) frequency response (from 0.01 to 0.64 Hz). Fifty-two normal subjects volunteered for this test. The transfer function's gain and phase, and the corresponding coherence function between slow phase eye velocity and head velocity were computed. According to the linearity hypothesis, the results match the sinusoidal stimulation studies. In both cases, the variability of the gain was higher than that of the phase shift. Identification of some parameters of the VeOR's mathematical model were performed, using the experimental results.

Adult↗

PubMed1997

Multivariate time-variant identification of cardiovascular variability signals: a beat-to-beat spectral parameter estimation in vasovagal syncope.

In this paper a bivariate, time-variant model able to continuously measure the mutual interactions between heart rate and systolic blood pressure variability signals is presented. A recursive identification of the model parameters makes it possible to estimate, on a beat-to-beat basis, spectral low-frequency (LF) and high-frequency (HF) power, (LF/HF ratio) and cross-spectral (coherence and phase relationships between spectral peaks) indexes during nonstationary events. These indexes can be helpful in: 1) physiological study of autonomic nervous system mechanisms of cardiovascular control and 2) quantification and clinical evaluation of the neural and mechanical links between the two signals. In addition, an estimate of baroreceptive activation (alpha-gain) is continuously extracted. Before applying the model to cardiovascular signals, the reliability of the estimated parameters was tested on simulated signals. Subsequently, the model was applied to investigating vasovagal syncope episodes, aiming at the assessment of autonomic nervous system status and autonomic role in the dynamic phenomena which lead to syncope. The proposed model, which provides noninvasive beat-to-beat evaluation of the autonomic events, may be useful in the description of the syncopal episodes and in the comprehension of the complex physiological mechanisms of syncope.

Algorithms↗