Recently, a new anthropometric method of accurate lower leg length measurement (knemometry) was introduced. The present study was performed to investigate rigorously its strengths and weaknesses for auxological purposes, and to promote a standardized method of use. The data are based on 6 x 2200 single estimations of the lower leg length in 90 children of both sexes with normal, tall or short stature aged between 2.4 and 17.1 years. The overall technical error of this measurement was found to be 0.16 mm, which is reduced to 0.13 mm if the first estimation within each series of six is ignored. The following sources of systematic error could be detected: intra-daily variation, dependency on physical pressure put on or removed from the leg, vigorous physical activity prior to the measuring procedure, and a slow but significant correlation between day-to-day variation of lower leg length and body weight (r = 0.299, b = 0.372 mm/kg). There was no covariation with atmospheric parameters such as outside temperature, barometric pressure and others. After elimination of a linear trend from the individual growth curves, there was a remaining day-to-day variation of SD = 0.697 mm. This represents real changes of lower leg length and cannot be explained by the technical error of measurement which contributes to less than 10% of the total variation. Some of this day-to-day variation may be explained by non-linearity of growth. Knemometry appears to be a robust and precise new tool for the investigation of short term kinetics of longitudinal growth. Proposals for a standardized use of this technique are given.

Adolescent↗

PubMedDate not supplied

Periodical changes of short term growth velocity ('mini growth spurts') in human growth.

Evidence has accumulated that predictions of annual or half-annual growth rates are of limited validity when derived from extrapolations of short term growth rates. In order to investigate whether the poor predictive qualities of short sections of individual growth curves are caused by non-linearity of human growth, we have studied 73 healthy children, aged 2.9 to 15.9 years, with standard deviation scores for body height ranging between -3.3 and +3.0. The children were measured between 18 and 106 times once or twice per week throughout periods of 180 to 306 days by knemometry, a novel and noninvasive technique of accurate lower leg length measurement. Non-linearity of growth was found in about 70% of those children who could be measured more than 35 times. 45 children provided evidence for a characteristic up-and-down pattern of lower leg growth velocity consisting of sharp growth spurts ('mini growth spurts') alternating with periods of decreased growth velocity every 30 to 55 days. This pattern seemed to appear spontaneously, though in some cases we found a marked coincidence between periods of growth arrest and intermittent infectious illness.

Adolescent↗

PubMedDate not supplied

The association between birth order and adult stature.

First-borns are smaller than later-borns at birth. We investigated adult stature of families with three or more adult children, aged between 20 and 70 (mean 32) years. There was no significant correlation between size of the family and final adult stature of the siblings. We found a mean height reduction of first-borns compared to the mean of all sibs of -1.2 cm (P less than 0.02 using conventional analysis of variance, P less than 0.05 using nonparametric prediction configural frequency analysis). Males tend to increase in height with increasing birth order, whereas females do not beyond the second-born. These observations could not be explained by decreasing age of later-born sibs, nor by periods of malnutrition immediately after the war (1945-1948). Thus, we conclude that birth order is a factor that contributes significantly to the variance of adult height within sibships.

Adult↗

PubMedDate not supplied

Micro and macro perspectives in auxology: findings and considerations upon the variability of short term and individual growth and the stability of population derived parameters.

The present paper links the two most contrasting aspects of auxology, and addresses the apparent discrepancy between the variability and pulsatility of short term individual growth, and the stability of population derived parameters. When body stature is measured at monthly intervals, an irregular incremental pattern becomes obvious, with a number of large scale components such as series of prepubertal and pubertal growth spurts, seasonal influences on height gain, and influences of the psychosocial and economic background. When measurement intervals decrease, the patterns of stature increment appear even more irregular, and a number of short scale components become apparent, that are distinct from measurement error. Observations are presented that suggest growth being a pulsatile, a periodic, a saltatory, respectively a chaotic event as suggested by some recent studies in animals and in human newborns. Accurate measurements of the lower leg at intervals of 24 hours support the idea of short term growth being characterized by chaotic series of 'mini growth spurts' that occur at intervals of approximately 4-9 days. The amplitude of mini growth spurts ranges between 2 and some 10 mm, and also growth velocity of each spurt varies considerably so that one spurt needs between less than one and up to several days for completion. The very opposite of the variability of individual growth was found in populations. A meta-analysis of 40 male and 51 female European and US American growth studies revealed an almost uniform general pattern of average stature increment during the last 100 years. An additional analysis of stature variation of very large Japanese and Czechoslovakian growth surveys, with all together more than 23000000 measurements, and more than 500000 German preschool and school measurements, suggested similar uniformity in the standard deviation of stature.

Animals↗

PubMedDate not supplied

Wrinkles induced by the use of smoothing procedures applied to serial growth data.

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Biometry↗

PubMedDate not supplied

Electrophysiologic and antiarrhythmic effects of phentolamine in experimental coronary artery occlusion and reperfusion in the dog.

We studied the electrophysiologic and antiarrhythmic effects of phentolamine on ventricular arrhythmias seen after acute coronary artery occlusion and reperfusion in the anesthetized dog. One group of animals underwent proximal left circumflex artery occlusion for 1 hr followed by 4 hr of reperfusion. One-half received phentolamine, 0.25 mg/kg bolus, 30 min before occlusion, followed by continuous intravenous infusion of 0.15 mg/kg/min throughout the experiment, while the other half received saline and served as controls. Phentolamine reduced the number of premature ventricular contractions (PVCs) during the reperfusion period but had no effect on postocclusion arrhythmias. Another group of dogs underwent ligation of two consecutive left anterior descending diagonal branches for 1 hr followed by reperfusion. Effective refractory periods and ventricular activation times were measured before occlusion, every 10 min during occlusion, and every 10 min during reperfusion in both normal and ischemic zones. In this model, phentolamine reduced both the number of PVCs and the complexity of ventricular ectopy seen in the first 10 min after reperfusion. Compared to control, phentolamine decreased the shortening of ischemic zone refractory period seen after occlusion and prevented the overshoot seen after reperfusion. Phentolamine had no effect on ventricular activation times or mean blood pressure. Phentolamine is effective in preventing reperfusion ventricular arrhythmias and may act by decreasing the dispersion of refractoriness between normal and ischemic zones during coronary occlusion and reperfusion and by preventing the rapid increase in refractory period after reperfusion.

Animals↗

PubMedDate not supplied

Development of a sterilizing in-place application for a production machine using Vaporized Hydrogen Peroxide.

The use of steam in sterilization processes is limited by the implementation of heat-sensitive components inside the machines to be sterilized. Alternative low-temperature sterilization methods need to be found and their suitability evaluated. Vaporized Hydrogen Peroxide (VHP) technology was adapted for a production machine consisting of highly sensitive pressure sensors and thermo-labile air tube systems. This new kind of "cold" surface sterilization, known from the Barrier Isolator Technology, is based on the controlled release of hydrogen peroxide vapour into sealed enclosures. A mobile VHP generator was used to generate the hydrogen peroxide vapour. The unit was combined with the air conduction system of the production machine. Terminal vacuum pumps were installed to distribute the gas within the production machine and for its elimination. In order to control the sterilization process, different physical process monitors were incorporated. The validation of the process was based on biological indicators (Geobacillus stearothermophilus). The Limited Spearman Karber Method (LSKM) was used to statistically evaluate the sterilization process. The results show that it is possible to sterilize surfaces in a complex tube system with the use of gaseous hydrogen peroxide. A total microbial reduction of 6 log units was reached.

Disinfectants↗

PubMedDate not supplied

Jaime Burmeister. Interview by Jessica Bell.

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Career Choice↗