SEARCH · Search PubMed

Results for “Statistical Distributions”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

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

At least 829 records · Page 46Linked to original sources

PubMed1987

[Critical evaluation of changes in circulating blood volume, hematocrit, hemoglobin and plasma protein concentration for the calculation of normotonic fluid losses].

Normotonic fluid losses always lead to intravascular hypovolemia and subsequently to hypovolemic shock. Unfortunately, there are no diagnostic methods sufficient to calculate the extent of normotonic losses for fluid therapy. Therefore, indirect parameters such as changes in hemoglobin concentration, hematocrit, or plasma protein concentration are usually used for monitoring fluid therapy. This paper presents the results of our study in ten healthy volunteers. We investigated whether changes in circulating blood volume or hematocrit, hemoglobin, and plasma protein concentration indicate the amount of normotonic fluid loss in dehydrated humans. Normotonic fluid losses were induced using furosemide in repeated doses of 20 mg. Control measurements were carried out before furosemide administration (ZDM1 = time of sample taken) and after 2000 (ZDM2) and 3000 ml urinary output (ZDM3). We measured hematocrit as well as concentrations of hemoglobin, plasma protein, sodium, potassium, and chloride using standard laboratory methods. Hematocrit values were corrected for trapped plasma (3%) and the body/venous hematocrit ratio (0.91). Circulating blood volume was measured using J-131 RIHSA and the "volemetron" introduced by Williams and Fine. Plasma volume and plasma water volume were calculated. After checking the data for normal distribution, statistics were calculated using the paired t test (P less than 0.01). The results are listed in Table 2. We calculated normotonic fluid losses on the basis of plasma and urinary sodium concentrations and found them to be 1720 +/- 155 ml (ZDM2) and 2392 +/- 262 ml (ZDM3).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1977

[Mechanism of genetic recombination in bacterial conjugation. VIII. The heterogeneity of the progeny of exconjugants].

It is shown on several examples that the heterogeneity of recombinant clones after conjugation is independent on the conditions of primary selection (i.e. on the yield of primary clones). Therefore the prediction of the model of autonomously multiplying donor fragments is not confirmed by experimental data. Two additional characteristics of heterogeneity are introduced. The statistical distribution of merozygotes according to segregation time is measured. It is an exponential curve with a relaxation time approximately coinsident with the third cell division. A liner function is found for the dependence of heterogeneity on the distance between the selective and non-selective markers. The highest value for non-linked markers is about 15%. Alternative models for the explanation of the heterogeneity of exconjugants are discussed.

Bacteria↗

PubMed1979

[The evolution of the thickness of rabbit corneas in hydratation, the influence of pH and composition of the solution (author's transl)].

The swelling of excised, de epitheliated, rabbit corneas has been measured every five minutes during their immersion in a hydrating medium. The following media have been used: distilled H2O, Krebs-bicarbonate Ringer solution, HCl 0,01 N and NaCl 1 M/l. The swelling is very moderate with Krebs and NaCl, much higher and practically proportional to the duration of immersion with HCl, still faster with H2O. On the other hand, the influence of pH has been studied using 13 different solutions buffered from pH 1 to pH 13. A pronounced minimum of the swelling was found for pH 4, along with 3 relative maxima: the first around pH 2, the second around pH 8 and the third around pH 12. The interpretation of those results on a biochemical basis is discussed. For all these media, the solvent was distilled H2O. At last, two statistical distributions, based on 131 corneas, have been determined: one concerning the initial thickness and the other concerning the difference between the initial thickness of the two corneas of the same rabbit.

Animals↗

PubMed1985

[Magnesium, calcium, zinc, potassium, total and HDL cholesterol and total creatine kinase in 37 cases of instable angina: a correlation study].

Plasma and erythrocyte magnesium (P-Mg, E-Mg), zinc (P-Zn, E-Zn) and potassium (P-K, E-K), plasma calcium (P-Ca), HDL-cholesterol and total cholesterol and total creatine kinase (TCK) were determined in 37 cases (26 men, 11 women) of unstable angina pectoris (UAP) on the first day of hospitalization. The same variables, except P-K and TCK, were measured in 58 male and 53 female reference subjects. The methods of measurement were emission spectrometry for K, atomic absorption spectrometry for Mg, Ca and Zn, and the R CK NAC-activated Merckotest for TCK. According to the normality of distributions, statistical analysis of results was performed either by parametric or nonparametric tests. Multiple (R), simple (r) and Spearman (rs) correlation coefficients were calculated, and only significant correlations (p less than or equal to 0.05) were accepted. There was no significant R for UAP patients. For UAP men, r was negative and significant between P-Mg and E-K, but positive between P-Ca and P-Zn, as for reference subjects; and rs was negative and significant between P-Zn and TCK. For UAP women, only rs was positive and significant, between P-Mg and TCK. In the UAP population, contrary to the reference population, there were no significant differences relative to sex. In comparison with reference men, UAP men presented a significant (p less than 0.005) increase in E-Mg and significant (p less than 0.001) decreases in P-Ca and P-Zn.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMedDate not supplied

Plasma concentrations of FSH and testosterone in male infertile patients.

We studied the statistical distribution of the plasma concentrations of FSH and testosterone in patients with oligoazoospermia as compared with normospermic subjects. The plasma concentration of FSH was determined in 429 patients with oligoazoospermia and 282 normospermic subjects ("controls"). In 118 out of these 429 patients and in 47 of the 282 controls, the plasma concentration of testosterone was also measured. The plasma concentrations of FSH differed significantly depending on the patients' values of spermatic concentration. The most significant difference was observed between azoospermic patients and controls, whereas the difference between patients with mild oligospermia and controls was not significant. Conversely, the plasma concentrations of testosterone did not correlate with the values of spermatic concentration and even the difference between azoospermic patients and controls did not reach the significance level. In addition, testosterone plasma concentrations did not differ between two sub-groups of patients who were defined depending on whether the plasma concentration of FSH was normal or high. Our findings confirm the inverse relation between plasma FSH levels and spermatic concentration which had already been observed in previous studies. However, a considerable overlap in the plasma concentrations of FSH has been found between sub-groups of patients with different spermatic concentrations. This overlap limits the clinical usefulness of the measurement of FSH concentration inasmuch as normal FSH plasma levels may often be associated with any value of spermatic concentration. Also, our data confirm that the measurement of testosterone plasma levels provides little clinical usefulness in male infertile patients.

Adult↗

PubMed1985

Serum IgE level in systemic lupus erythematosus.

The serum total-IgE level has been studied in systemic lupus erythematosus (SLE), in order to obtain data concerning the significance of IgE antibodies in the appearance of SLE symptoms. In most patients the serum IgE content was significantly higher in the active stage of the disease than during remission. The findings indicated a specific statistical distribution due to the multiple factors influencing IgE production and so an augmented IgE level cannot be regarded as a reliable feature of SLE activation.

Humans↗

PubMed1985

[Population patterns in the development and course of endogenous psychoses as a reflection of their pathogenesis].

An analysis of a representative epidemiological sample of patients with endogenic psychoses (schizophrenia and MDP) revealed statistical distribution of some parameters of the disease (risk of the development of the disease in relation to age, a number of previous attacks, as well as distribution of patients by the duration of paroxysms and remissions). The authors believe that a collation of the tabulated data with the known mathematical models makes it possible to come to understanding some aspects of the pathogenesis of endogenic psychoses.

Adolescent↗

PubMed1985

[Importance of thyroid hormone determination in the diagnosis of hyperthyroidism--significant improvement in medical assessment using decision theory results].

A "schematic" classification of the results of serum thyroid hormone measurements on the basis of mathematical decision theory proves to be superior to the physicians' conventional evaluation. That has been shown by comparison with the evaluations made by three experienced doctors. When using no control regions (but the results of serum T4, FT4 and T3 simultaneously) the physicians' rates of misrecognition (0-2% false positives, 20-27% false negatives) are only a little lower than when classifying schematically on the basis of only one thyroid hormone. The construction of a suitable control region, however, results when T3 alone is used, in only 7% false negative and 0% false positive results, while these rates remain nearly unchanged for the physicians' evaluations. The optimum application of mathematical decision theory is only possible with the knowledge of the statistical distributions of the thyroid hormone data, both for a representative collective of normals and that of patients with proven hyperthyroidism. Thus, quantitative criteria for the effectiveness of each set of thyroid hormones can be constructed and a multivariate analysis can be performed, in our example - when applying suitable control regions - even with vanishing rates of misrecognition.

Decision Theory↗

PubMed1979

[Normal values and diagnostic reliability of laboratory tests].

After an introduction on various aspects marking the reliability of analytical data, the AA. discuss the diagnostic value of laboratory tests dwelling upon three important moments regarding the necessity to examine closely the nature of biologic parameters and their nosological meaning, their statistical distribution in a population and some concepts of Normality that may be found in Clinical Chemistry.

Clinical Laboratory Techniques↗

PubMed1978

[Results of a predictive trial of the response to nomifensine in ambulatory patients].

Nine hundred and fifty eight cases of neurotic-secondary ambulatory depression were treated with nomifensin by 135 psychiatrists. The analysis of visual analogue scales and of the global assessment shows that:--there were 2/3 responders and 1/3 non-responders--the most improved items were: crying, troubles in getting to sleep, abnormal tiredness, anxiety;--associated drugs from the beginning were frequent. They seemed to correspond to different initial symptomatologies but the final state did not differ substantially;--discrimination methods (linear discriminant function, stepwise discrimination) could separate groups of responders and non-responders, but did not allow for a valid individual prediction;--admist possible causes of these misclassifications, several factors are discussed: patient selection, choice of the variables, skewed or bimodal distributions, statistical methods used, acurateness of quotation, spectrum of the stutied drug.

Adjustment Disorders↗

PubMed1977

[Noise in a foundry: measurement and evaluation].

The results of the noise measurements obtained in three foundries, two of cast-iron and one of aluminium, are reported. Because of noise level variations, a level recorder and a statistical distribution analyzer have been used in addition to a sound level meter, and thus equivalent continuous sound levels (Leq) both with factor q = 3 (European Code) and with factor q = 5 (OSHA) have been calculated. The results obtained with these two different criteria of evaluation are discussed.

Aluminum↗

PubMed1984

[Prospects for environment intervention following biological monitoring of exposure to chromium].

The authors study the statistical distribution and the graphical representation of the urinary chromium values investigated during three consecutive years in three work environments of a same plant: polishing 1 degree, electrotyping, polishing 2 degrees, to evaluate the environmental situations of exposure and their variations. The adopted method, based on the graphical representation of the values in logarithmic coordinate paper, allows to quickly and carefully calculate the percent of the workers having urinary chromium values above the prefixed limits.

Chromium↗

PubMed1983

On a foundation of the Ellis-formula and Strandqvist-function with kinetic equations.

The Ellis-formula and Strandqvist-function are a useful tool for the treatment of a relationship between time, dose and fractionation in radiation therapy and experimental radiobiology. They can formally be derived from kinetic principles and relaxation methods in chemistry and physics, if all biochemical processes induced by an irradiation are described by a statistical distribution function of relaxations and by a Laplace transformation leading to a Markoff chain. In this way, the connection between kinetic processes in cellular tissue and the empirical relationship of the Ellis-formula and Strandqvist-function can be made apparent.

Humans↗

PubMed1983

[Inflammatory reaction to polyester material in the guinea pig. V. Semiautomatic determination of peritoneal cell volume].

The volume of the peritoneal cells of guinea pigs treated with injections of 1) minced polyester threads (Mersilene), 2) saline, and of untreated animals, has been determined utilizing a Coulter Counter coupled with a pulse height analyzer. The volumetric test on the whole cell population has emphasized a distinctly bimodal distribution, due to the presence of two cellular types picked out as first peak (P 1 degrees) and second peak (P 2 degrees), while the non-adherent cells (CNA) have shown an unimodal distribution. Statistically significant difference in the mean volumes have been found between the P 1 degrees and P 2 degrees cells and between the CNA and P 1 degrees cells. The percentage of CNA in the whole cell population significantly decreases in "Mersilene"-treated guinea pigs.

Animals↗

PubMed1984

[Partial and combined effect of arterial hypertension and atherogenic shifts in blood lipid fractions on the incidence of ischemic heart disease].

The results of a purposeful epidemiologic study involving 3896 men and 1502 women aged 40-69 years from the same city district are presented. To correlate the prevalence of coronary heart disease (CHD) and the level of arterial pressure (AP), subjects with a low coefficient of atherogenicity (a ratio of pre-beta-and beta-lipoproteins to alpha-lipoproteins) from the first quartil (1360) and the fourth quartil (1325) were selected. The statistical distribution series was plotted for each decade of age in males and females differentially. The atherogenic composition of blood lipids was found to be the risk factor determining CHD incidence in males aged 40-59 and 50-59 and in females aged 50-59, whereas in subjects over 60 years of both sexes it was elevated AP levels. The presence of two leading CHD risk factors was associated with a considerable increase in CHD prevalence in all age groups of both sexes.

Adult↗

PubMed1983

[Possibilities of the epidemiologic method and various results of a population study of schizophrenia].

Some results of the epidemiological studies on schizophrenia conducted recently by the Epidemiology Department of the Psychiatry Institute, the USSR Academy of Medical Sciences, are summed up. The principal demographic data on schizophrenia, such as its prevalence and forms as well as the pathogenetic role of the sex and age are presented. Taking the paroxysmal forms as a model, the application of the epidemiological method in investigating the course and probable prognosis of schizophrenia is reviewed in greater detail. On the basis of the material from a representative group of patients with paroxysmal schizophrenia of the 15-year duration or over (1461 patients), the basic regularities of the time course of negative and positive disturbances during remission, as well as the specific features of the shift in the clinical forms of paroxysms are demonstrated. Statistical distribution shows that in most patients, the distinctive signs of a given form of the disease course tend to remain unaltered during the whole period of the illness. Apart from reflecting the stability of patterns of the disease course, these findings support the validity of the current schizophrenia differentiation.

Age Factors↗

PubMed1982

Public health training programs at the University of the West Indies.

The Department of Preventive Medicine of the University of the West Indies was established in 1957 with the idea of improving undergraduate teaching facilities to enable medical students to study patients in their homes and social environment. The authors describe the two public health diploma programs available at the University and cite pertinent enrollment and geographic distribution statistics. Candidates for the Diploma in Public Health are registered medical practitioners who take a series of compulsory and elective subjects and have a period of supervised field training and research during the 12-month course. The Diploma in Community Health trains students in the health and diseases of man in his total environment. Students choose among three program options: the general program, specialization in health education, or specialization in health services administration/hospital administration. The general program is the most popular because it gives the student a rounded education suitable to the needs of small states. The 12-month diploma course features the interdisciplinary approach where students from various fields discuss important issues in community health. Comprehensive courses in these areas include health services administration, social sciences, environmental health, epidemiology and biostatistics, family health, communication science, and community mental health. The authors state that the candidate for the Diploma in Community Health is assessed on the basis of course and field work, a special project report, and a final written and oral examination.

Curriculum↗

PubMed1982

[Incidence of paranoid schizophrenia].

The incidence of paranoid schizophrenia (the number of new cases per year) was examined in a population. The figure was found to be 0.17 per 10,000 of the population, being greatly dependent on the age and sex structure of the population examined. The method of the examination is presented in detail. It is shown, in particular, that the results are considerably influenced by the disease duration in the patients. With a short duration of the disease the results appear to be greatly underestimated because of the difficulties in making the correct diagnosis in many cases. The exact number of such cases can be determined by using the law of statistical distribution of the duration of the paranoid schizophrenia stages.

Adult↗