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PubMedDate not supplied

Nutritional status improvement in neurologically impaired patients by percutaneous endoscopic gastrostomy feeding.

With increased use of percutaneous endoscopic gastrostomy, it became clear that neurologically impaired patients might benefit from its use. From August 1996 to July 1997, we performed 19 percutaneous endoscopic gastrostomies in patients with neurological sequelae, who were incapable to maintain their nutritional status by oral ingestion or had repeated episodes of aspiration. Sixteen patients were followed prospectively, from 30 days to 11 months (median: 6.4 months). Average weight (38.2 kg to 44.8 kg), BMI (14.8 kg/m2 to 17.8 kg/m2), weight/height ratio (23.5 kg/cm to 28 kg/cm), mid-upper arm circumference (19.4 cm to 21.6 cm) and triceps skinfold thickness (10.3 mm to 12.6 mm) were significantly increased (P < 0.01). Before percutaneous endoscopic gastrostomy, there were 10 (10/16, 62.5%) patients with grade III thinness. In this group, 3/10 patients (30%) showed improvement to grade I (two individuals) and II (one patient). All but five patients (68.75%) were below the fifth percentile of normal distribution for mid-upper arm circumference. One patient (6.2%) showed improvement of her status (between 25th and 50th percentiles). Four patients (25%) started the follow-up below the fifth percentile for normal distribution of triceps skinfold thickness, and showed no improvement. There were no early complications secondary the procedure. Late complications included granulation tissue on ostomy site (18.8%) and ostomy infection (6.2%). Statistical analysis showed significant improvement of anthropometric data. Percutaneous endoscopic gastrostomy is a simple, highly successful and safe procedure, when performed in neurologically impaired patients. It is efficient as a long-term enteral feeding method.

Adolescent↗

PubMed2000

Normal ranges of neuropsychological tests for the diagnosis of Alzheimer's disease.

The diagnosis of early stage dementia is a highly complex process involving not only a somatic examination but also a neuropsychological assessment of the patient's cognitive capability. The American 'Consortium to Establish a Registry for Alzheimer's Disease' (CERAD) has proposed a set of tests in English which has been translated into German. This paper presents the statistical methodology applied to determine normal ranges adjusted for demographic variables for the German CERAD neuropsychological assessment battery (CERAD-NAB). The study population consists of participants of the Basel Study on the Elderly (Project BASEL) which aims at identifying preclinical markers of Alzheimer's disease. The normative sample has been defined by carefully excluding potentially relevant medical history and concomitant diseases and consists of 617 participants which are between 53 and 92 years old. Test results should be adjusted for gender, age, and years of education. For this purpose, a set of linear models including these predictors and subsets of their interactions and squares was evaluated for all 11 test scores derived from the CERAD-NAB battery. Model selection was based on the PRESS (predicted residual sum of squares) statistic. Although a strict application of this criterion selected 6 different models, a slight compromise allowed to fit all test scores by two models. In several tests of the CERAD-NAB many participants achieve maximal scores. Residuals of such test scores are heavily skewed. An arcsine transformation has been tuned to the data, so that residuals are close to a normal distribution, at least for residuals in the lower quartile which is relevant in diagnosing cognitive impairment. Test results are finally presented as z-scores which can be easily compared to a standard normal distribution. The evaluation of the CERAD-NAB is implemented on the Internet and in an Excel application.

Aged↗

PubMed1977

[Use of the straightened diagram method in morphologic studies].

A possibility is demonstrated to use a technical method of strahtened diagrams in order to check hypotheses of normal distribution for treating experimental morphological data. The method is a graphic interpretation of experimental values in the coordinate system: measured values (abscissa) and accumulated frequences (ordinate). In the case of the law on normal distribution, the experimental dots are distributed closely enough to the straight line drawn along the average arithmetic parameters of observation and their mean square deflection. Confidence intervals plotted on the diagram accurately enough serv as a criterion for the experimental dots proximity to the straight line. The order of calculation to build the straightened diagram for a large (several hundreds) number of values is represented. An example is given when the method is not applied.

Anatomy↗

PubMed1991

The distribution of the intervals between neural impulses in the maintained discharges of retinal ganglion cells.

Simulated neural impulse trains were generated by a digital realization of the integrate-and-fire model. The variability in these impulse trains had as its origin a random noise of specified distribution. Three different distributions were used: the normal (Gaussian) distribution (no skew, normokurtic), a first-order gamma distribution (positive skew, leptokurtic), and a uniform distribution (no skew, platykurtic). Despite these differences in the distribution of the variability, the distributions of the intervals between impulses were nearly indistinguishable. These inter-impulse distributions were better fit with a hyperbolic gamma distribution than a hyperbolic normal distribution, although one might expect a better approximation for normally distributed inverse intervals. Consideration of why the inter-impulse distribution is independent of the distribution of the causative noise suggests two putative interval distributions that do not depend on the assumed noise distribution: the log normal distribution, which is predicated on the assumption that long intervals occur with the joint probability of small input values, and the random walk equation, which is the diffusion equation applied to a random walk model of the impulse generating process. Either of these equations provides a more satisfactory fit to the simulated impulse trains than the hyperbolic normal or hyperbolic gamma distributions. These equations also provide better fits to impulse trains derived from the maintained discharges of ganglion cells in the retinae of cats or goldfish. It is noted that both equations are free from the constraint that the coefficient of variation (CV) have a maximum of unity.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1978

Electrophoretic mobility distributions of normal human T and B lymphocytes and of peripheral blood lymphoblasts in acute lymphocytic leukemia: effects of neuraminidase and of solvent ionic strength.

Human T and B lymphocytes were found to be distinguishable on the basis of electrophoretic mobility, with the T cells having the higher mobility, in agreement with previous reports. The effects of the enzyme neuraminidase on the electrophoretic mobilities of T and B lymphocytes were determined. T lymphocytes showed a greater decrease in electrophoretic mobility after neuraminidase treatment; the relative mobilities of T and B cells were reversed by neuraminidase treatment, and the electrophoretic distinguishability was enhanced. The electrophoretic mobility distributions of lymphoblasts from patients with acute lymphocytic leukemia were found to differ from those of normal cells in their response to neuraminidase treatment and to changes in solution ionic strength. These results imply that the surface structure of the leukemic cells differs from that of either T or B lymphocytes from normal donors.

B-Lymphocytes↗

PubMed1987

An analysis of numerical models of air pollutant exposure and vegetation response.

A number of empirical (statistical, regression oriented) and mechanistic (process oriented) models are presently available to examine the relationship between air pollution stress and plant response. These models have their strengths and weaknesses. In all these models, a major concern is the numerical definition of the pollutant exposure kinetics (dose). At present there are no numerical definitions of dose which make satisfactory biological sense. A key issue is the existence of a biological time clock where plants respond differently to the pollutant stress at different stages of their growth. On the other hand, policy makers and regulatory personnel prefer a simple approach which would facilitate implementation and administration of ambient air quality standards. Long-term air pollutant averaging techniques create artifacts due to the non-normal distribution of ambient concentrations. A more appropriate approach may be the use of 'median' and 'percentiles' computed from short duration pollutant concentrations. Such an approach would be free of the influence of the non-normal distribution, but would require the development of appropriate exposure-response models. Any transfer of results from unit level models to regional level leads to 'scaling error'. There is no general agreement among researchers on how to deal with the scale problem. While this situation persists, any policy formulated on regional impact assessment must acknowledge the uncertainty.

Journal Article↗

PubMed1993

Photosynthetic Characteristics of Segregates from Hybrids between Flaveria brownii (C4 Like) and Flaveria linearis (C3-C4).

Characteristics related to C4 photosynthesis were studied in reciprocal F1 hybrids and F2 plants from Flaveria brownii (C4 like) and Flaveria linearis (C3-C4). The reciprocal F1 plants differed in 13C/12C ratios of leaves and the percentage of 14C initially incorporated into C4 acids, being more like the pollen parents in these traits. They did not differ in apparent photosynthesis or in O2 inhibition of apparent photosynthesis and differed only slightly in CO2 compensation concentration at 175 [mu]mol quanta m-2 s-1 and 400 mL L-1 O2. The 13C/12C ratios of 78 F2 progeny from the two F1 plants exhibited a normal distribution centered between those of the parents, with a few values slightly higher and lower than the parents. Apparent photosynthesis at 130 [mu]L L-1 CO2 and inhibition of photosynthesis by O2 was nearly normally distributed in the F2 population, but no values for F2 plants approached those for F. brownii (15.4 [mu]mol m-2 s-1 and 7.8%, respectively). Distribution of the CO2 compensation concentration measured at 1000 [mu]mol quanta m-2 s-1 and 400 mL L-1 of O2 in the F2 population was skewed toward F. brownii with 72% of the progeny having values <9 [mu]L of CO2 L-1 compared to 1.5 and 27.2 [mu]L L-1 for F. brownii and F. linearis, respectively. Correlations among traits of F2 plants were low (coefficients of 0.30 to -0.49), indicating that the C4- related traits are not closely linked in segregating populations. Plants in the F2 population selected for high or low apparent photosynthesis at 130 [mu]L of CO2 L-1 (six each) did not rank consistently high or low for 13C/12C ratios, O2 inhibition of apparent photosynthesis, CO2 compensation concentration, or activities of phosphoenolpyruvate carboxylase or NADP-malic enzyme. This study confirms results of earlier work that indicates independent segregation of C4 traits and also shows that the C4-like parental type can be recovered, at least for some characteristics (13C/12C ratio), in segregating populations. Recovery of fully functional C4 plants awaits further experimentation with C4 x C3 or C4 x C3-C4 hybrid plants that produce fertile progeny.

Journal Article↗

PubMed1994

Relationship of ultrasonographic findings to histology in prostate cancer.

We compared ultrasonic findings and histology in 25 patients with prostate cancer. Ultrasonically guided transperineal biopsy of focal prostatic lesions was performed in 19 patients, in whom prostate cancer was suspected. Six of them had two different echogenic areas in the same focal lesion, so a total of 25 echogenic areas were assessed. Fourteen of these 25 areas were hypoechoic. The Gleason score varied, but residual prostatic glands and cancer glands with slightly enlarged lumen did not exist. Six of the areas were slightly more echogenic than the above 14 areas, and cribriform cancer with slightly enlarged glands occupied the greater part of these specimens. Four of the areas were isoechoic, and they contained residual prostatic glands showing a normal distribution, regardless of the Gleason score or grade of tumor infiltration. The only hyperechoic lesion contained numerous tiny areas of calcification. In the 6 patients without focal lesions, the peripheral and transition zones showed a normal echogenicity. Two of these patients had cancer in the transition zone, and biopsy showed tumor glands with slightly enlarged lumens. In the 4 patients, various-sized tumors were seen, but there was a normal distribution of residual prostatic glands and stroma. These results indicated that prostatic echogenicity is determined by the presence of tumor glands with enlarged lumina as well as residual prostatic glands and stroma.

Adenocarcinoma↗

PubMed1978

[Normal values of the caloric test (author's transl)].

Normal values of the caloric test are reported in 202 healthy subjects; besides the absolute values, these comprise the degree of side-difference of excitability and of directional preponderence in percent of the total reaction. In addition to mean values with standard deviations, the median values and the interquantile areas 80, 90, 94 and 100% have been reproduced in tabular form, because, according to statistical calculations, there is no normal distribution of the values in the strict sense. The problematic nature of borderline values for the separation of physiological from pathological responses is discussed in detail. In vieu of the considerable scattering, a knowledge of normal distribution areas appears to be absolutely necessary for an accurate evaluation of the caloric test in patients.

Adult↗

PubMed1980

[Morphology and biochemistry of blood of various mustelids. 3. Enzymographic studies of arterial plasma of mink (Mustela vison Schreber, 1777)].

Twelve different enzyme activities, which are listed and explained in greater detail in Table 2, were determined statistically secured, and discussed, following a three-year study into arterial plasma of 118 female and 124 male minks, aged between six and seven months and kept under anaesthesia. Simply normally distributed or logarithmically distributed plasma enzyme activities were found to differ primarily by sex, with other experimental conditions being identical and regular. The enzyme activities of ICDH, active CPK, and total LDH (the latter only with females) were normally distributed, whereas all the other enzymes activities tested, except for gamma-GT and SDH, were of Gaussian distribution only after logarithmic transformation of the individual values. The plasma enzyme activities of GPT, LAP, ChE, LDH1, MDH, and AP differed from those of GOT, gamma-GT, SDH, total LDH and active CPK, in that they usually exhibited highly significant sex-related differences. All minks were tranquilised and kept under general anaesthesia, using neuroleptanalgesia, but all their enzyme activities were found to vary just as widely as those reported elsewhere in literature, in the context of minks without anaesthesia. The latter result was experimentally confirmed by means of a model experiment in which enzyme activities were recorded from nine male ferrets, prior to, during, and after neuroleptanalgesia.

Alcohol Oxidoreductases↗

PubMed1990

Land snails as experimental animals: a study of the variability and distribution of individual weights in Helix aspersa snails born from the same clutch.

A study was carried out to examine the distribution of individual weights in Helix aspersa snails, the aims being to establish the best estimate of the ponderal growth and also to obtain a model growth curve. Four groups of 20 snails from the same clutch were analysed and kept under experimental conditions from birth up to 6 months. The variability of their individual weights within groups was studied by calculating the coefficients of variation every 15 days. At the same time, the assumed normal distribution of those weights was being tested. The coefficients of variation increased with age and the assumed normal distribution of individual weights had to be rejected. By means of a log transformation of the original data, a model growth curve was constructed, and was used to assess the possibility of estimating age from weight. We finally reached the conclusion that median weight, rather than the mean, would be a better measure of central tendency to use until it is possible to obtain selected populations. The difficulty of estimating age from weight is emphasized.

Age Factors↗

PubMed2005

The role of Munc18-1 in docking and exocytosis of peptide hormone vesicles in the anterior pituitary.

BACKGROUND INFORMATION: Many neurons secrete classical transmitters from synaptic vesicles as well as peptide transmitters from LDCVs (large dense-core vesicles). Little is known about the mechanistic differences between these two secretory pathways. The soluble protein Munc18-1 is essential for synaptic vesicle secretion [Verhage, Maia, Plomp, Brussaard, Heeroma, Vermeer, Toonen, Hammer, van den Berg, Missler, et al. (2000) Science 287, 864-869.]. RESULTS: In the present study, we tested if Munc18 genes are also involved in peptidergic secretion from LDCVs using the anterior pituitary as a model system. We show that Munc18-1 is the dominant isoform expressed in the anterior pituitary. In Munc18-1 null mutant mice, the anterior pituitary developed normally and the five major endocrine cell types had a normal distribution. However, circulating peptide hormone levels were decreased by up to 50-fold in the null mutant, whereas the intracellular levels were significantly higher than that in controls. Ultrastructural analysis using the tannic acid method revealed striking differences in the distribution of secretory vesicles: (i) the number of exocytotic figures was mostly decreased in the null mutants and (ii) the LDCVs accumulated near but not at their target membrane. This is in contrast with the apparently normal distribution of synaptic vesicles in developing synapses in the null mutant (Verhage et al., 2000). CONCLUSIONS: We conclude that Munc18-1 is involved in the secretion of peptide hormones and in the docking of LDCVs. These results unmask an apparent mechanistic difference between LDCVs and synaptic vesicles.

Animals↗

PubMed1992

Submucosal glands are the predominant site of CFTR expression in the human bronchus.

We have used in situ hybridization and immunocytochemistry to characterize the cellular distribution of cystic fibrosis (CF) gene expression in human bronchus. The cystic fibrosis transmembrane conductance regular (CFTR) was primarily localized to cells of submucosal glands in bronchial tissues from non-CF individuals notably in the serous component of the secretory tubules as well as a subpopulation of cells in ducts. Normal distribution of CFTR mRNA was found in CF tissues while expression of CFTR protein was genotype specific, with delta F508 homozygotes demonstrating no detectable protein and compound heterozygotes expressing decreased levels of normally distributed protein. Our data suggest mechanisms whereby defects in CFTR expression could lead to abnormal production of mucus in human lung.

Bronchi↗

PubMed1991

Myosin heavy chain isoform distribution in normal and hypertrophied rat aortic smooth muscle.

Causes of hypertension have been well scrutinized, whereas the secondary, disabling effects of high blood pressure are less well investigated. We have used a rat model of hypertension and developed a technique to study the secondary vascular smooth muscle component of the disorder. Banding patterns of myosin heavy chain isoforms from rat aortae were examined using denaturing electrophoresis, Western blotting, immunochemical identification, and degradation studies. Myofibrillar ATPase activities were also measured. Left ventricular hypertrophy and hypertension were induced in rats by aortic banding just proximal to the renal artery. Aortic banding increased the heart weight/body weight (mg/g) ratio from 2.8 to 3.8 and mean aortic weight by 53%. Two distinct myosin heavy chain isoforms, molecular masses of 204 and 200 kDa, were identified by 4% sodium dodecyl sulphate-polyacrylamide electrophoresis of crude aortic extracts from normal rats in a relative molar ratio of 1.54:1. The development of significant thickening of the aorta was marked by substantial increases in aortic wall smooth muscle content but was not associated with any changes in distribution of the isoforms. The band patterns obtained on gel electrophoresis were not the result of contamination by other proteins, as Western blotting studies with specific antibodies demonstrated that the isoforms were smooth muscle in origin and were not derived from nonmuscle myosin sources. Myofibrillar ATPase activity of aortic smooth muscle from hypertensive rats was increased. It is suggested that this increase may be the result of post-transcriptional alterations of one or more sarcomeric proteins involved in the regulation of smooth muscle contraction.

Adenosine Triphosphatases↗

PubMedDate not supplied

[Nonuniform dose distributions in normal body organs and tissues in the radiotherapy of malignant tumors].

A mathematical model has been developed to evaluate the nonuniform impact of tissue radiation exposure in an equal dose (or an effective dose). The equal dose (or effective dose) is that of the uniform tissue radiation, which is equivalent to the nonuniform distribution of a dose. The paper presents a mathematical analysis of the model and studies its properties. The factor that can be regarded as a measure for systemic reparative tissue capacity against radiation exposure is identified.

Humans↗

PubMed1990

Subcellular distribution of myocardial 5'-nucleotidase.

The controversial subject of the subcellular location of myocardial adenosine production was studied employing density gradient fractionation of heart muscle combined with a novel method for analyzing distribution profiles based on multiple regression (correlation) analysis. Bungarotoxin binding, N-acetyl-beta-D-glucosaminidase, cytochrome c oxidase, NADPH-dependent cytochrome c reductase and lactate dehydrogenase were used as markers for the plasma membrane, lysosomes, mitochondria, sarcoplasmic reticulum and cytosol, respectively. The normalized distribution frequencies (fraction of total) of 5'-nucleotidase in mitochondria, lysosomes, plasma membranes, sarcoplasmic reticulum and cytosol in the 50 x g supernatant of total homogenate of heart muscle were found to be 0, 0.25, 0.44, 0.08 and 0.23, respectively. To increase the resolution power of this approach with respect to mitochondria, a crude mitochondrial fraction was also studied, in which the normalized distribution of 5'-nucleotidase in the homogenate was 0, 0.16 and 0.84 in mitochondria, plasma membranes and lysosomes, respectively. This mainly lysosomal 5'-nucleotidase activity was 61% inhibited by the alpha,beta-methylene analog of ADP, indicating that although the latter has been considered specific to the plasma membrane enzyme, it also inhibits the lysosomal enzyme. The intercellular distribution of 5'-nucleotidase was not studied, but the lack of this enzyme in the mitochondria indicate that the adenosine production observed during mitochondrial AMP production, e.g. during acetate oxidation in intact heart muscle, must involve AMP transport out from the mitochondria.

5'-Nucleotidase↗

PubMed2005

Adequate margins for random setup uncertainties in head-and-neck IMRT.

PURPOSE: To investigate the effect of random setup uncertainties on the highly conformal dose distributions produced by intensity-modulated radiotherapy (IMRT) for clinical head-and-neck cancer patients and to determine adequate margins to account for those uncertainties. METHODS AND MATERIALS: We have implemented in our clinical treatment planning system the possibility of simulating normally distributed patient setup displacements, translations, and rotations. The planning CT data of 8 patients with Stage T1-T3N0M0 oropharyngeal cancer were used. The clinical target volumes of the primary tumor (CTV(primary)) and of the lymph nodes (CTV(elective)) were expanded by 0.0, 1.5, 3.0, and 5.0 mm in all directions, creating the planning target volumes (PTVs). We performed IMRT dose calculation using our class solution for each PTV margin, resulting in the conventional static plans. Then, the system recalculated the plan for each positioning displacement derived from a normal distribution with sigma = 2 mm and sigma = 4 mm (standard deviation) for translational deviations and sigma = 1 degrees for rotational deviations. The dose distributions of the 30 fractions were summed, resulting in the actual plan. The CTV dose coverage of the actual plans was compared with that of the static plans. RESULTS: Random translational deviations of sigma = 2 mm and rotational deviations of sigma = 1 degrees did not affect the CTV(primary) volume receiving 95% of the prescribed dose (V(95)) regardless of the PTV margin used. A V(95) reduction of 3% and 1% for a 0.0-mm and 1.5-mm PTV margin, respectively, was observed for sigma = 4 mm. The V(95) of the CTV(elective) contralateral was approximately 1% and 5% lower than that of the static plan for sigma = 2 mm and sigma = 4 mm, respectively, and for PTV margins <5.0 mm. An additional reduction of 1% was observed when rotational deviations were included. The same effect was observed for the CTV(elective) ipsilateral but with smaller dose differences than those for the contralateral side. The effect of the random uncertainties on the mean dose to the parotid glands was not significant. The maximal dose to the spinal cord increased by a maximum of 3 Gy. CONCLUSIONS: The margins to account for random setup uncertainties, in our clinical IMRT solution, should be 1.5 mm and 3.0 mm in the case of sigma = 2 mm and sigma = 4 mm, respectively, for the CTV(primary). Larger margins (5.0 mm), however, should be applied to the CTV(elective), if the goal of treatment is a V(95) value of at least 99%.

Head and Neck Neoplasms↗

PubMed2001

Mid-trial design reviews for sequential clinical trials.

When sequential clinical trials are conducted by plotting a statistic measuring treatment difference against another measuring information, power is guaranteed regardless of nuisance parameters. However, values need to be assigned to nuisance parameters in order to gain an impression of the sample size distribution. Each interim analysis provides an opportunity to re-evaluate the relationship between sample size and information. In this paper we discuss such mid-trial design reviews. In the special cases of trials with a relatively short recruitment phase followed by a longer period of follow-up, and of normally distributed responses, mid-trial design reviews are particularly important. Examples are given of the various situations considered, and extensive simulations are reported demonstrating the validity of the review procedure in the case of normally distributed responses.

Cardiovascular Diseases↗