Morphological and biochemical effects of strenuous exercise on immature long bones.

To determine the effects of intense exercise on the growth of long bones in immature animals, young male white leghorn chickens were run five days per week starting at four weeks of age on motor-driven treadmills. Work intensity was determined on the basis of maximal oxygen consumption (VO2 max) with the exercise intensity maintained at 70-80 percent VO2 max. Young animals ran continuously for 30 minutes, older animals 45 to 60 minutes each day.

Effects of microgravity on the composition of the intervertebral disk.

The lumbar annuli of rats flown on COSMOS 2044 were compared with those of three control groups and a tail-suspension experimental model. The wet and dry weights of the annuli were significantly smaller (P less than 0.05) in the flight group than in three control groups.

Response of immature chicken meniscus to strenuous exercise: biochemical studies of proteoglycan and collagen.

Male white Leghorn chickens were exercised on a treadmill at 70-80% of their maximal oxygen consumption starting at 4 weeks and continuing up to 20 weeks of age. The effect of the strenuous exercise regime on the extracellular matrix of menisci was followed through studies of proteoglycans and collagen. Avian menisci contain type I collagen, chondroitin sulfate proteoglycans, which increase with age in amount and degree of aggregation, and dermatan sulfate proteoglycans, which decrease with age.

Structural and mechanical adaptation of immature bone to strenuous exercise.

To investigate the adaptive responses of immature bone to increased loads, young (3-wk-old) White Leghorn roosters were subjected to moderately intense treadmill running for 5 or 9 wk. The training program induced significant increases in maximal O2 consumption and muscle fumarase activity in the 12-wk-old birds, demonstrating that growing chickens have the ability to enhance their aerobic capacity. The structural and mechanical properties of the runners' tarsometatarsus bones were compared with sedentary age-matched controls at 8 and 12 wk of age.

Patellar tendon matrix changes associated with aging and voluntary exercise.

Male rats maintained under constant environmental conditions were randomly assigned to nonrunner (NR) and voluntary exercise (R) groups. At 9 mo, voluntary exercise significantly increased muscle cytochrome c concentration and citrate synthase activity. Also, at the same age, R animals had significantly greater glycosaminoglycan concentration than NR, but no changes in dry weight and collagen concentration were significant.

Proteoglycans of human infant intervertebral disc. Electron microscopic and biochemical studies.

The ground substance of the intervertebral disc consists primarily of proteoglycans, which give the tissue its stiffness to compression and its resiliency. To investigate the structure and composition of these molecules, we extracted them from human infant nucleus pulposus under associative conditions and from human infant annulus fibrosus and cartilage end-plate under dissociative conditions. We examined the degree of aggregation, the composition, the electron microscopic appearance, and the dimensions of the proteoglycans of the intervertebral disc and compared their structure and dimensions with those of the proteoglycans from bovine hyaline cartilage.

Morphological and biochemical effects of sodium morrhuate on tendons.

The purpose of this study was to determine some of the morphological and biochemical effects of sodium morrhuate injections into intact rabbit patellar tendons and Achilles tendons. The effects of one, three, and five 100 microliters injections of sodium morrhuate on tendon circumference, cell content, collagen fibril diameter, collagen-proteoglycan relationships, water content, amino sugar content, and hydroxyproline content were investigated over periods of 1, 4, and 9 weeks. In general, sodium morrhuate injected tendons were larger in diameter and contained more cells, smaller collagen fibrils, increased water and amino sugar content, and reduced hydroxyproline content compared with their contralateral controls.

Pseudoachondroplasia: biochemical and histochemical studies of cartilage.

Cartilage from patients with pseudoachondroplasia is characterized by unique inclusions in the cisternae of the endoplasmic reticulum and proteoglycan abnormalities have been suggested in this form of dwarfism. To elucidate the nature of the proteoglycan defect, we determined the amount of the individual glycosaminoglycans present in iliac-crest cartilage of three patients and extracted the proteoglycan monomers from one of the samples. Sections of iliac-crest cartilage and proximal fibular growth plates were examined by electron microscopy and also stained with hematoxylin and eosin, safranin O-fast green, and alcian blue in the presence of increasing concentrations of magnesium chloride (zero to one molar).

Inherited metabolic myopathy with storage of glycoproteins and glycosaminoglycans.

Two related patients (mother and daughter, ages 28 and 5 years) showed mild to moderate weakness and atrophy of facial and shoulder muscles with congenital onset and minimal progression. Serum creatine kinase was elevated in the child. Muscle biopsy showed normal light-microscopic and histochemical findings, but scattered sarcoplasmic vacuoles with storage of granular material were evident on electron microscopy.

Histochemical properties of cartilage proteoglycans.

Proteoglycan interaction with alcian blue at different concentrations of magnesium chloride was studied both in vitro and in histological sections of paraffin-embedded tissues. Our experiments indicate that a) proteoglycans with different contents of chondroitin sulfate and keratan sulfate, prepared under nondegradative conditions, are not distinguishable on the basis of the critical electrolyte concentrations at which staining is abolished; b) the state of aggregation of proteoglycans only very slightly affects the alcian blue affinity of the macromolecules at different concentrations of magnesium chloride; c) the interaction of proteoglycans with other components of the connective tissue matrix is an important factor in determining the strength of binding of alcian blue to the polyanionic macromolecules in histological sections. These factors should be considered in interpreting histochemical data obtained by staining tissue sections with alcian blue at different concentrations of magnesium chloride.

Proteoglycans and glycosaminoglycans of human achondroplastic cartilage.

To determine whether proteoglycans or glycosaminoglycans from human achondroplastic cartilage are structurally abnormal, we isolated and characterized proteoglycans and glycosaminoglycans from fibular growth plates and from cartilage of the iliac crests of patients with achondroplasia. The glycosaminoglycans of both achondroplastic fibular growth plates and achondroplastic iliac-crest cartilage showed no differences from those isolated from normal tissues. Proteoglycans of achondroplastic iliac-crest cartilage were indistinguishable from those of controls.

The effect of various decalcifying agents on cartilage proteoglycans.

Mineralized and unmineralized cartilages were treated with various decalcifying solutions to investigate proteoglycan loss after decalcification. Five percent formic acid decalcifies quickly and causes only minimal loss of uronic acid from calcified cartilage which cannot be appreciated by histochemical means. On the basis of our findings formic acid should be considered an excellent decalcifying agent for proteoglycan histochemistry in paraffin embedded cartilage.

Pepsin-solubilized collagen of human nucleus pulposus and annulus fibrosus.

Human nucleus pulposus and annulus fibrosus, obtained at autopsy from patients 7-30 years of age, were extracted with 2 M guanidine-HCl (pH 5.82) to remove proteoglycans, then stirred with pepsin in 0.5 M acetic acid, followed by three 24-h extractions with 1 M NaCl (pH 7.

Pathogenesis of scoliosis.

Scoliosis often occurs in otherwise normal individuals or it may be associated with many widely differing diseases. The curve patterns are fairly uniform and the vertebrae always rotate in the frontal and horizontal planes producing convex side rotation with little displacement of the spinuous processes. Many small curves do not increase.