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At least 163 records · Page 9Linked to original sources
PubMed1996

[Normal distribution of CBF with advancing age measured by HMPAO SPECT].

SPECT with Tc-99m HMPAO was used to determine global and regional cerebral blood flow (CBF) in 52 healthy subjects ranging from 2 to 85 years old. These subjects were divided into six groups according to age. SPECT images were obtained using a three-headed gamma camera system equipped with low-energy ultra-high-resolution fan beam collimators (LEUHR-FAN). Absolute CBF values were estimated in 21 of 52 subjects using a Patlak plot technique. The SPECT images were obtained 5-10 minutes after the injection of 740MBq of Tc-99m HMPAO. A supercomputer system was used to reconstruct transverse section images at levels of 8, 32, 44 and 67 mm above the orbitomeatal line (2.7 mm thickness), and oblique transverse section images parallel to the temporal lobe (1.56 mm thickness). Lassen's linearization correction was applied. The average counts of four or five ROIs in eight regions were calculated. The cerebral to cerebellar activity ratio (C/C ratio) was estimated by dividing counts in the cerebral regions by those in the cerebellum. The interhemispheric differences in C/C ratios in the eight regions of all the groups were not significant. In elderly subjects there was a tendency for C/C ratios to decrease except in the thalamus and basal ganglia. Mean global CBF in 21 of 52 subjects was 49.3 +/- 10 ml/100g/min. A significant negative correlation was found between global CBF and advancing age (p < 0.05), particularly in males (p < 0.01).

Adolescent↗
PubMed1992

Bronchoalveolar lavage cellularity. The distribution in normal volunteers.

Bronchoalveolar lavage (BAL) is used to obtain inflammatory cells from the lung. For clinical research, parametric statistics are frequently used to compare cells present in BAL of patients with lung disease with cells present in BAL of normal subjects. To determine if these populations can be compared in this manner we performed BAL on 111 never-smoking, normal volunteers and determined: (1) the mean, median, standard deviation, and range of the cells in BAL; (2) whether the data are normally distributed and satisfy the criteria for use of parametric statistical analysis. The BAL cellularity was expressed as a percentage of total cells, cells per milliliter return, and total cells per lavage. Regardless of the means of expression, no measure of BAL cellularity (total cells, macrophages, lymphocytes, neutrophils, or eosinophils) conformed to the normal (bell-shaped) distribution when tested for goodness of fit with the G statistic (all p < 0.001). The lack of fit to the normal distribution was not substantially altered by either the method of expressing the data (i.e., cells per milliliter, total cells, or percent of cells) or log transformation of the data. The poor fit in all cases resulted from clumping of the data about the mean and large tails. The percent of cells were, therefore, tested for goodness of fit to the Poisson distribution, a distribution of discrete variables. The neutrophil and eosinophil percentages resulted in an excellent fit to the Poisson distribution, but macrophage and lymphocyte percentages did not.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

Sulfur colloid distribution in normal hips.

The normal distribution of Tc-99m sulfur colloid is described in 100 patients with no clinical or radiographic evidence of hip disorders. Two-thirds of the patients had uptake in the femoral neck and some uptake in the femoral head. In the other one-third, no uptake was detected in either femoral head. A high degree of symmetry was noted. Judging both the symmetry and pattern of uptake in both hips is important in evaluating femoral head vasculature after a fracture.

Adolescent↗
PubMed1982

Statistical properties of responses to dichotic listening with CV nonsense syllables.

Twenty-four listeners received 20 dichotic listening runs of 30 pairs of natural CV nonsense syllables per run. Left- and eight-ear responses are represented by two partially overlapping normal distributions with equal variance. Observed ear advantages across listening runs are also distributed normally. The means of the distribution of ear advantage are listener specific, but the standard deviations are 10.8% +/- 2.5. The origin of reversals in direction of ear advantage among listening runs is statistical--a small mean/sigma ratio--and approximately six listening runs (180 listening trials) are required to achieve a split-half reliability coefficient of + 0.90.

Dominance, Cerebral↗
PubMed1989

[Hemodynamic state at rest and during maximal bicycle exercise in university students with small cardiac silhouettes on chest radiography].

To clarify the hemodynamic state of an apparently small heart; i.e., a small cardiac silhouette on chest radiography, chest radiographic and echocardiographic studies, physical fitness tests (a battery of tests consisting of vertical jump, side step, floor push-up, and modified Harvard step test) and graded uninterrupted bicycle exercise test were performed. 1. The cardiothoracic ratio (CTR) in 3,461 newly-enrolled university students (18.7 +/- 1.2 years old: mean +/- SD) distributed normally and the mean value +/- SD was 40.2 +/- 3.6%. No difference was observed between male and female students. 2. A small heart was defined as one having a cardiothoracic ratio (CTR) less than or equal to 35% which comprised the lower 10% of the normal distribution. There was no significant difference in results of physical fitness tests between students with small heart (n = 134) and normal controls (n = 136, 45% less than or equal to CTR less than or equal to 50%). 3. A maximal bicycle exercise test was performed in 14 male students with small heart (S: CTR = 31.9 +/- 2.1%) and nine normal controls (C: CTR = 46.5 +/- 1.0%). a) Body weight (S: 57 +/- 7, C: 69 +/- 8 kg, p less than 0.001) were less in students with small heart; Body height was similar in both categories (S: 171 +/- 5, C: 175 +/- 7 cm, NS). b) All controls finished 200 W workload, whereas all students with small heart ceased exercise earlier than the control subjects (three at 125 W, three at 150 W, eight at 175 W). c) Resting heart rate was higher in cases with small heart (S: 92 +/- 14, C: 77 +/- 10 beats/min, p less than 0.02). Left ventricular end-diastolic dimension was smaller in small heart (S: 39 +/- 4, C: 48 +/- 4 mm, p less than 0.001). d) During exercise, blood pressure and oxygen intake at the same workload were similar in both groups, but peak oxygen uptake was higher in the controls (S: 43 +/- 5, C: 50 +/- 7 ml/kg/ml, p less than 0.05). Heart rate and blood lactate concentration were higher throughout exercise in students with small heart (lactate at 175 W; S: 12.7 +/- 1.6, C: 7.8 +/- 2.0 mmol/L, p less than 0.001) (heart rate at 175 W; S: 194 +/- 6, C: 173 +/- 21 beats/min, p less than 0.05). We concluded that hemodynamic conditions at rest and during low grade exercise are preserved in students with small heart.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗