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Biomedical subjects

E Schultz

Publications and source records attributed to E Schultz.

At least 127 records · Page 7Linked to original sources
PubMed1984

A quantitative study of satellite cells in regenerated soleus and extensor digitorum longus muscles.

Satellite cells quantitated in the rat soleus and extensor digitorum longus (EDL) muscles following a complete regeneration returned to "normal" percentages of myofiber nuclei in both muscles 3 months after injury. Following cross-transplantation, the percentage of satellite cell nuclei in the EDL regenerated in the soleus bed was indistinguishable from the percentage in the soleus. Likewise, the soleus muscle regenerated in the EDL bed had a satellite cell percentage characteristic of the EDL. These results suggest that 1) the proportion of satellite cells is reestablished in a regenerated muscle and 2) the innervating nerve determines the proportion of satellite cell nuclei in a muscle.

Animals↗
PubMed1984

25-Hydroxyvitamin D concentrations in maternal and cord blood at delivery and in maternal blood during lactation in Finland.

The 25-hydroxyvitamin D concentration (25-OHD) in maternal and cord blood of 192 mothers was determined at delivery from June to the end of November. Ninety-nine mothers had received a daily supplementation of 12.5 micrograms of vitamin D during pregnancy and this group had a significantly higher 25-OHD concentration both in maternal and in cord blood than in the corresponding non-supplemented group. A daily supplement of 2.5 micrograms of vitamin D was given to 63 of the mothers during lactation. Of these mothers 44 were still lactating after 6 months. The dietary vitamin D intake of 31 mothers was calculated. We found a significant correlation between the maternal serum 25-OHD concentration 16-18 weeks after delivery and the total vitamin D intake. The intake (5.5 micrograms/d, including supplementation) was lower than that recommended for lactating mothers which is 10 micrograms/d (Food and Nutrition Board, 1980).

Adolescent↗
PubMed1983

Age-related differences in absolute numbers of skeletal muscle satellite cells.

The absolute number of satellite cells (SC) in young and adult rat skeletal muscle was estimated by correlating data from light and electron microscopic quantitation of myofiber nuclei (myonuclei and satellite cell nuclei) with biochemical assays for determining total muscle DNA content. Expressed both as a proportion of total myofiber nuclei and as absolute numbers, satellite cells are more numerous in the predominantly oxidative soleus muscle than in the mixed glycolytic/oxidative extensor digitorum longus (EDL) muscle at 1, 12, and 24 months of age. Satellite cell proportions decline gradually in both muscles with advancing age, but absolute numbers increase significantly in the soleus between 1 and 12 months, while EDL exhibits a continuous significant decline in satellite cells between each of the ages examined.

Age Factors↗
PubMed1983

[Resolving power of digital subtraction angiography (DSA). Measurements of opacification with different blood vessel calibers and constrictions in relation to contrast media concentration].

The demonstration of contrast-filled vessels by means of digital subtraction angiography has already proved a valuable clinical method (1 to 14). The present paper provides data on measured opacification as related to vessel calibre and contrast concentration. It is further shown in which degree narrowing of vessels can be ascertained dependent on vessel size and contrast concentration. Finally, the spatial resolution of the method has been investigated by using phantoms. It was shown that the resolution depends on the direction of the vessels within the projected area.

Angiography↗
PubMed1983

Phantom measurements and error estimation in volume determination with ECG-triggered cardio-computed tomography.

The ECG-triggered CT-imaging-procedure (computed tomography system SOMATOM with ECG unit) provides the possibility of displaying the beating heart in each of its individual mobility phases. Thus the telediastolic and telesystolic volumes of the left ventricle can be determined approximately, and from this its ejection fraction. The present paper describes measurements on moving phantoms (acryl plate, fluid-filled balloon). They give an estimation of the accuracy with which cross-sectional areas can be determined by the above-mentioned CT-system as a function of the frequency of the movement and of the number of tube rotations per slice. Basing on those models and not paying regard to further sources of error as for example an irregular heartbeat, it is found that the ejection fraction can be determined with a relative error of +/- 11% . . . +/- 13% depending on the beat frequency.

Cardiac Output↗
PubMed1982

The distribution of satellite cells and their relationship to specific fiber types in soleus and extensor digitorum longus muscles.

Fiber type classification of p-phenylene-diamine-stained transverse sections of rat skeletal muscle correlated with electron microscopic observations demonstrate that satellite cells are not equally distributed among the various fiber types in either the EDL or soleus at 1 and 12 months of age. Of the three fiber types in the EDL, satellite cells are observed most frequently on Type IIA fibers, and at approximately equal frequencies on Type IIB and Type I fibers. Satellite cells in the soleus, in contrast to the EDL, are not often encountered on Type IIA fibers, but are preferentially associated with Type I fibers in that muscle. The frequency with which satellite cells are found on specific fiber types is distinct for the soleus and EDL and appears to correspond with their growth characteristics. The distribution of satellite cells according to fiber type does not provide an explanation for the differences in the percentage of satellite cell nuclei between the EDL and soleus.

Animals↗
PubMed1982

Skeletal muscle satellite cells: changes in proliferation potential as a function of age.

Skeletal muscle satellite cells were isolated from soleus and extensor digitorum longus muscles of Sprague-Dawley rats at selected ages between 6 days and 30 months and grown in cell culture. Cells at each donor age were monitored individually to determine the number of progeny they were capable of producing. Under identical in vitro conditions, the average number of progeny produced was inversely proportional to donor age. Hence, the proliferation potential of satellite cells decreases with age.

Aging↗
PubMed1982

[Measurements in triggered CT imaging of moving objects].

This paper describes results of measurements characterising the image properties of a CT apparatus triggered by an "R-peak simulator". For this purpose, a phantom was constructed in which--as straightforward simulation of a cardiac wall movement--a plate made of plexiglass of 5 mm wall thickness moves to and fro with a frequency nu (1 s-1 less than or equal to nu less than or equal to 2 s-1) and an amplitude of A = 10 mm. The number of scanning cycles during a measurement could be varied between 2 and 9. It was evident that the measured density values as well as the positions of the plate which could be ascertained from the CT images in the various phases of movement, especially at low frequencies and a large number of cycles, agree well with the real values; however, it was also found that both at the measured density values and the positions of the plate as seen from the CT images, systematic deviations occur, especially at high frequencies and a small number of scanning cycles.

Electrocardiography↗
PubMed1981

[Effects of beam weakening and beam hardening on the measured CT values].

The present article reports on the effects of weakening and hardening of radiation on CT values in the environment of highly absorptive materials, using phantoms for carrying out these measurements. First of all, it was found with the help of geometrically simple phantoms (discs, circular rings), that the measured CT value of each volume element depends on the density distribution in the environment and that the CT values of homogeneous object layer are not uniform, but clearly dependent on the location at which measurement is effected. The standard deviation of the CT values of a homogeneous part of an object layer was also found to depend on the environment. Finally, using anatomically relevant phantoms, it was found that density value changes from max. +20 HU to -65 HU occur in the region of the cranium, whereas in the environment of the lumbar vertebra the density varies between max. +20 HU and -10 HU; in the pleural region, the maximum density variations are +/- 10 HU.

Humans↗
PubMed1980

Rattlesnake shaker muscle: I. A light microscopic and histochemical study.

Rattlesnake body and shaker muscles were studied using light microscopy and histochemistry. Five myofiber types are distinguishable in the body musculature. The majority are large diameter fast twitch fibers with high alkaline-stable ATPase activity and few mitochondria. In the shaker muscle the major fiber differs from all body fibers in that myofibrils do not entirely fill the fibers. The myofibrils branch repeatedly with one another, which leaves large areas of sarcoplasm devoid of filaments and gives the fibers a characteristic mottled appearance. Mitochondria and glycogen deposits are very numerous. Shaker fibers have high alkaline stable ATPase activity and, in addition, stain intensely for NADH-TR and alpha GPD. Myofibers of the shaker muscle are unusual in that they are extremely fast contracting yet are highly fatigue resistant.

Adenosine Triphosphatases↗
PubMed1980

Rattlesnake shaker muscle: II. Fine structure.

The shaker muscle of the rattlesnake is able to sustain a rate of contraction around 50/sec for at least 3 hr. Most of the muscle is composed of a single, major fiber type which contains large numbers of small myofibrils, abundant sarcomplasmic reticulum, numerous mitochondria, and large deposits of glycogen. The neuromuscsular junction of the major fiber type is extensive with several nerve terminal expansions and junctional folds that are both numerous and deep. The structure of the major fiber type suggests that it must be responsible both for the speed of contraction as well as for the indefatigability of the shaker muscle. The ultrastructure of the much less numerous minor fibers in the shaker muscle suggest that their role may be a tonic one.

Animals↗
PubMed1980

[Organ volume determination by computer tomography. I. The estimation of organ sectional areas with special reference to possible errors (author's transl)].

With the aid of computer tomography it is possible to determine the volume or organs by obtaining an adequate number of CT cuts through the area of interest, and by marking the organ contours. Various sources of error must be taken into account when using this method; some of these are systematic and others accidental. In particular it must be remembered that there may be errors in obtaining cross-sectional areas from the organ contours, since these vary depending on the chosen parameters, such as window level and position. These relationships, which depend on the apparatus, are developed theoretically and confirmed by measurements. It is shown that errors depend not only on the choice of window level, but also on the shape and size of the organ and on the surrounding contrast. It follows that it is possible to introduce corrections for the cross-sectional area, but that the size and shape of the section need to be taken into account, at least to some extent.

Anatomy↗