Ultrastructural effects of immobilization on rat muscle spindles

The ultrastructure of rat muscle spindles was examined after the anterior tibial muscles had been immobilized in a plaster cast. There was an increase in the number of collagen fibrils and external laminae around the outer capsules and in the intracapsular space 2 weeks after immobilization. The changes in the intrafusal muscle fibers within 4 weeks included disorientation of myofilaments. After 6 weeks, Z bands had become disarranged, and there was vacuolar degeneration of the sarcoplasmic reticulum in some fibers. Myelin sheaths of many of the myelinated nerve fibers (especially the thick ones, which were probably sensory nerve fibers) had degenerated within 2 weeks. These results indicate that immobilization of skeletal muscles affects not only extrafusal muscle fibers but also the structure of the muscle spindle.     

Tibial changes in experimental disuse osteoporosis in the monkey

Summary We studied the mechanical properties and structural changes in the monkey tibia with disuse osteoporosis and during subsequent recovery. Bone bending stiffness was evaluated in relationship to microscopic changes in cortical bone and Norland bone mineral analysis. Restraint in the semireclined position produced regional losses of bone most obviously in the anterior-proximal tibiae. Following 6 months of restraint, the greatest losses of bone mineral in the proximal tibiae ranged from 23% to 31%; the largest changes in bone stiffness ranged from 36% to 40%. Approximately 8 ? months of recovery were required for restoration of normal bending properties. However, even after 15 months of recovery, bone mineral content did not necessarily return to normal levels. Histologically, resorption cavities in cortical bone were seen within 1 month of restraint; by 2 ? months of restraint there were large resorption cavities subperiosteally, endosteally, and intracortically. After 15 months of recovery, the cortex consisted mainly of first-generation haversian systems. After 40 months, the cortex appeared normal with numerous secondary and tertiary generations of haversian systems.     

The effects of long-term immobilization on the histomorphology of human cortical bone

Summary The cortical bone histomorphometrics, total visible osteon density, and mean osteonal cross-sectional area were determined for the major long bones and sixth ribs of two individuals with neurological deficit. One was a multiple sclerosis patient who had been in a wheelchair for 15 years. The other was a quadriplegic as a result of poliomyelitis. Statistically significant differences in osteon densities occurred only in the case of the quadriplegic. Nevertheless, in that subject, the total visible osteon densities for bones of the right arm were not statistically different from those of their age-matched (control) radii. Medical history records revealed that there had been partial use of this limb. These results support the belief that mechanical stress is an important factor in the maintenance of normal cortical bone remodeling. In addition, since there were subnormal osteon densities and normal mean osteonal cross-sectional areas, immobilization appears to be characterized by reduced activation frequency with a normal amount of bone turnover per BMU.     

Surgical exposure of the brachial plexus

A method of exposure of the brachial plexus is presented. Resection of the clavicle is emphasized in repairing large defects in the plexus to obtain primary anastomosis.     

The effect of short-term calcitonin administration on biochemical bone markers in patients with acute immobilization following hip fracture

The effect of salmon calcitonin on changes in mineral metabolism was studied in 40 elderly patients with recent hip fracture. All patients underwent surgery (internal fixation) 1 week after admission and were randomly divided into two equal groups: group A, which received no treatment, and group B, which received 100 IU/day salmon calcitonin intramuscularly for 2 weeks starting on admission. Blood and 24-h urine parameters of mineral metabolism were measured on admission and at the end of weeks 1 and 2. No intra- or intergroup changes in serum calcium, phosphorus or alkaline phosphatase were observed. At the end of week 2 biochemical markers of bone resorption (urinary calcium and hydroxyproline) had significantly increased in group A and significantly decreased in group B, indicating a reduction in bone resorption in group B. Urinary phosphorus had also increased in group B, possibly due to the phosphaturic effect of calcitonin. It is concluded that immobilization resulting from a hip fracture, and possibly surgery itself, causes significant changes in biochemical markers of bone resorption. Calcitonin successfully reverses these changes and may also be effective in preventing subsequent bone loss, particularly in patients who cannot be remobilized immediately.     

A head holder for treatment of head and neck cancers

A modified Frank Scholz head holder for immobilization of the head and neck is described and found to be reliably effective for daily radiation therapy.     

Unit-activity in the central amygdalar nucleus of rats in response to immobilization—stress

Multiple-unit activity in the central nucleus of the amygdala of rats was measured during immobilization and during presentations of a white-noise stimulus that had been paired with the restraint treatment. Results showed that some units responded with an increase, others with a decrease in firing rate during immobilization. Several units also showed “conditioned” rate changes to the auditory stimulus. A behavioral assessment of the presumed conditioned aversive properties of the stimulus showed that the rats which had experienced the pairing of restraint and the noise stimulus escaped faster when presented with the stimulus than the unpaired controls. It is suggested that the central amygdala might be part of a system in which stressful inputs influence autonomic functions.     

The cingulate cortex and gastric pathology

Bilateral lesions in the anterior or posterior cingulate cortex were performed in rats. After a recovery period, the rats were immobilized for 24 hours. Results showed that posterior lesions increased the severity of the stomach pathology under restraint and non-restraint conditions. Anterior lesions, on the other hand, attenuated the effects of immobilization on gastric pathology. The data were discussed in reference to telencephalic limbic mechanisms and stress.     

Kindling in the amygdala and susceptibility to stress ulcers

Kindling in the centromedial amygdala facilitated the subsequent development of restraint-induced stomach ulcers in rats. It was suggested that the neuronal hyperexcitability produced by the kindling procedure led to an increased susceptibility to gastric pathology in response to stress.     

Evaluation of different mannan polysaccharide usage in enzyme-linked immunosorbent assay for specific antibodies determination

Polysaccharides as antigens impose the problem of the proper ELISA assay. The indirect coating using biotin-avidin or lectins are therefore used. We tried to clarify the efficiency of different approaches to this problem. Our experiments clearly demonstrate that direct coating with mannan polysaccharide on high binding ELISA plates is superior to any other combination using any intermediate protein. On the other hand, the direct coating of the normal ELISA plate with mannan was of significantly lower (P=0.008) efficiency. The use of protein cannot be avoided in normal microplates. All previous statements are supported by experimental data in the paper.