Regional adipose tissue cellularity in relation to metabolism in young and middle-aged women

Body composition and total number of fat cells were investigated in 31 randomly selected women 52 yr of age and in 13 young women (mean age 22 yr) whose body weights were within ±10% of the ideal weight. Two of the 52-yr-old women were obviously obese and excluded. Regional determinations of adipose tissue thickness, fat cell size, and number were also determined. Middleaged women had more body fat (BF) but a lower body cell mass (BCM) than the younger group. The increased BF in the middle-aged women was exclusively explained by larger fat cells, since the younger women had a significantly higher total number of fat cells. This increase was also found when differences in height, body weight, and body fat were matched out. Local fat cell number was also increased in the younger group. Local fat cell size was increased in all regions investigated in the middle-aged women, but the increase was particularly pronounced in the abdominal region. The highest degrees of correlation between fat cell sizes of different regions were found between the epigastric and hypogastric regions and between femoral and gluteal regions. Furthermore, the plasma insulin levels correlated with the fat cell sizes of the abdominal region but not with those of the femoral or gluteal regions.In conclusion, the data might indicate that the fat cells of the abdominal region are more sensitive to nutritional and/or hormonal factors than those of other regions. This may in turn indicate the existence of different fat cell populations.     

Peripheral arterial insufficiency and the fine structure of the gastrocnemius muscle

A detailed light- and electron microscopical study was carried out on biopsies from m. gastrocnemius of 14 male individuals with intermittent claudication. The morphometric data obtained showed a large number of significant correlations with clinical and physical parameters. Practically all sections also showed morphological abnormalities, such as a fibre necrosis, regeneration, angular fibres, fibre type grouping and abundant connective tissue. Finally, there were significant differences in the muscle fine structure between those patients recommended physical training and those selected for surgery. The results clearly show that the structure of the muscle fibres is well adapted to the functional circumstances. They also show that widespread fibre damage do occur in intermittently ischaemic musculature, even if no signs of macroscopical tissue damage are found at routine clinical examination. Furthermore, although the clinical and physical data on patients selected for physical training and vascular surgery respectively, are very similar, there seems to be other factors that clinically influence the differentiation of the patients into these two groups. When evaluating effects of different treatments on these two groups of patients, it is thus important to take into account that there may be differences in morphology even before they are subjected to the different treatments.     

Differences in fiber number and fiber type proportion within fascicles. A quantitative morphological study of whole vastus lateralis muscle from childhood to old age.

Data are presented on the number of fibers and the proportion of different fiber types within fascicles of whole vastus lateralis muscles from 5 male children, 5 to 15 years of age, and compared with results from 25 male adults, middle aged and old individuals. The results verify a difference in the proportion of fibers with different properties within a fascicle. The proportion of type 2 (fast twitch) fibers on the border of fascicles is larger than the proportion internally: the children have (P less than 0.01) greater difference than the adults and the middle aged, whereas the old have (P less than 0.001) less difference than the other age groups. The mean number of fibers per fascicle increases (P less than 0.05) from childhood to adult age, and thereafter reduces (P less than 0.01). The results imply that fascicles continuously rearrange during the normal growth and development and the normal aging process. It is argued that the causes of the difference in fiber type proportions within fascicles are local factors in the muscle, secondary to the overall age related functional demands put on the fiber population.     

Fatigue during dynamic muscle contractions in male sprinters and marathon runners: relationships between performance, electromyographic activity, muscle cross-sectional area and morphology

Knee extensor fatigue and endurance during repeated maximum isokinetic manoeuvres were studied in five sprinters and five marathon runners, all males. Fatigue and endurance were expressed in terms of output (contractional work, CW) and input (integrated electromyograms, iEMG), and was related to muscle fibre composition of m. vastus lateralis and to cross-sectional area (CSA) of m. quadriceps. The initially performed contractional work was positively related to the calculated absolute type II fibre area of m. vastus lateralis, but not to the cross-sectional area of m. quadriceps. During the first 25 contractions, sprinters fatigued, with a slope of decline in contractional work that was correlated to the absolute type II fibre area, also after correction of performed work for CSA of m. quadriceps. As the electromyographic activity decreased less than the contractional work, a drastic fall in the CW/iEMG ratio was found in the sprinter group. Three out of five sprinters could perform less than 50 knee extensions, due to subjective discomfort in tested thighs. In contrast, all marathon runners could, after a minor similar decline in electromyographic activity and contractional work during the first part of the experiment, maintain a steady-state endurance level of CW and iEMG throughout the test (200 knee extensions). In conclusion, fatigue during isokinetic maximal knee extensions is closely related to the muscle structure of m. vastus lateralis.     

Transpedicular segmental fixation: description of a new procedure

The treatment of unstable fractures of thoracolumbar vertebrae is a controversial issue in the orthopedic community. The various methods employed for operative stabilization of these injuries have to date been found to have major disadvantages. A new therapeutic principle and a new device for stable internal fixation are presented.     

Load pattern and pressure pain threshold in the upper trapezius muscle and psychosocial factors in medical secretaries with and without shoulder/neck disorders

 Object: A current hypothesis for the genesis of muscular complaints in the shoulder/neck region postulates that short periods with a completely relaxed muscle are essential to avoid complaints. Another hypothesis is that these disorders are related to psychosocial conditions at work. In order to test these hypotheses, 23 medical secretaries were investigated. Methods: The load pattern during work in the upper trapezius muscle bilaterally was assessed with electromyographic (EMG) technique and exposure variation analysis (EVA). In addition, pressure pain threshold (PPT) was measured on the trapezius muscle bilaterally and on the sternum. Psychosocial conditions at work were assessed with a questionnaire. Results: The medical secretaries with complaints had significantly fewer episodes with totally or close to totally relaxed muscle compared with the healthy group. The group with complaints tended to have a more monotonous load pattern at low load levels (approx. 1%–5% maximum voluntary contraction) while the healthy group had more frequent pauses but also somewhat more frequent short load peaks. The group with complaints showed lower PPT readings compared with the healthy group. However, the whole group had considerably lower PPTs than is usually reported in the literature. Of the 12 questions in the psychosocial questionnaire only one regarding work task satisfaction showed a significant difference between the two groups. Conclusion: Support is found for the hypothesis that secretaries without complaints have more frequent episodes with totally relaxed muscle. A significant difference is found regarding work task satisfaction. Received: 29 April 1996/Accepted: 20 September 1996     

Achilles tendon injury. 3. Structure of rabbit soleus muscles after immobilization at different positions

This investigation was designed to study the short and long term effects of inactivity on the fine structure of skeletal muscle tissue. Ankles of rabbits were unilaterally immobilized for one of three weeks. The knees were semiflexed and the feet were either in plantar or in dorsal flexed positions. The soleus muscles were examined immediately after removal of the plaster or after six months of observation. The muscle fibres, when immobilized in the slackened state, showed serious degenerative changes and Type 1 fibres, i.e. fibres lightly stained for myofibrillar ATPase at pH 9.4, were often necrotic. The fibre type ratio was changed when examined immediately after removal of the casts so that the relative number of Type 2 fibres was increased. If stretched, essentially normal morphology was seen. The contralateral soleus muscles, which were excessively weight-bearing during the plaster period, were characterized by small, sometimes necrotic, Type 2 fibres and splitting of Type 1 fibres. Whatever the reason for the structural changes it seems correct to point out to the surgeon that too much emphasis on tendon aspects implies certain risks. Overeagerness to obtain a safe way of unloading the tendon during the necessary period of immobilization after suture may result in longstanding damage to the muscle structure and, as a sequel, decreased strength.     

Morphometric analyses of human muscle fiber types

Fibers from the m. vastus lateralis of 10 middle-aged men were classified at ultrastructural level according to the appearance of the sarcomeric M-band. The Z-band widths had a two-peak distribution. One peak was due to type 1 fibers (mean 125 +/- 11 nm), the other to type 2 fibers. This latter could be separated into type 2A (101 +/- 9 nm) and type 2B (86 +/- 8 nm). About 83% of the fibers would have been correctly classified on the basis of the Z-band width alone. Mitochondrial volumes differed (type 1 5.6 +/- 0.8, 2A 4.0 +/- 0.8, and 2B 2.8 +/- 0.8%). However, only one third (37%) of the fibers would have been correctly classified if sorted according to this parameter. Mitochondrial volumes in the different fibers were correlated to mitochondrial enzymes, while fiber sizes and numbers were correlated to cytoplasmic variables. The correlations appeared mainly after a training program, suggesting that the relationships between structural and functional parameters are more obvious after adaptation to higher functional demands.     

Evaluation of 350 sciatic blocks in rheumatoid foot surgery

Summary Sciatic block with Mepivacaine (3–4 mg/kg) revealed successful in 91.9% of 340 rheumatoid patients with Keller/Clayton operation. In unsufficient blocks (8.1%) supplementary anesthesia by femoral nerve block, reblocking the sciatic nerve or local anesthetics secondarily gave good operating conditions. In three cases it was necessary to use additional spinal anesthesia. The concomitant sympathetic block gives an immediate cessation of sweating and a long lasting elevation of skin temperature.

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Zusammenfassung Blockierung des N. ischiadicus mit Mepivacaine (3–4 mg/kg) war erfolgreich in 91.9% von 340 Vorfußoperationen bei 340 Rheumapatienten. Bei nicht genügender Schmerzlosigkeit (8.1%) war es nötig auch den N. femoralis zu betäuben, die Ischiadicusblockierung zu repetieren oder eine zusätzliche lokale Betäubung zu verwenden. In 3 Fällen war es nötig mit Spinalanästhesie fortzusetzen. Die Ischiadicusbetäubung verursacht durch Blockierung der sympathischen Fasern auch eine unmittelbare Beendigung der Schweißsekretion und eine langdauernde Erhöhung der Hauttemperatur.