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Biomedical subjects

G C Robin

Publications and source records attributed to G C Robin.

At least 55 records · Page 3Linked to original sources
PubMed1982

The relationship between bone density, mineral content, and mechanical strength in the femoral neck.

The bone density, mineral content and average shear stress in bending at failure were measured in vitro in 33 femoral necks of women and men of different ages. The correlations between these three parameters as well as their correlation with the Singh index were carefully analyzed and found to show that the Singh index is of no clinical value. The best correlation exists between bone density and shear stress at failure. Practically no correlation is found between the breaking stress and Singh index. The breaking stress decreases with age much faster than the bone density or bone mineral content. The correlation between the work to fracture and the bone density or its mineral content is only moderate. The bone density is best indicator for the compressive bone strength. The changes of bone strength are apparently influenced by factors other than the bone density and mineral content, although the possibility that small changes in bone density or mineral content cause large changes in bone strength cannot be excluded.

Absorptiometry, Photon↗
PubMed1981

Diffusion chamber cultures of muscle from patients with scoliosis.

Explants from paraspinal muscles of patients with scoliosis were cultured in Millipore diffusion chambers placed in peritoneal cavities of mice. Three and four weeks of incubation produced a predominantly myogenic growth. Cell counts done on paraffin sections and on dissociated cells from the chambers showed that explants from the concavity of the spinal curvature grew better than those from the convexity. Since cells from injured muscles, when transplanted or cultured, are known to grow better than those from healthy control tissue, these findings support our previous morphologic observations that in idiopathic scoliosis concave muscles are more involved by the disease process. Secondary subculture of the chamber contents by conventional methods produced myotubes within one to two weeks. The relative ease of diffusion chamber muscle culture should make the method useful to laboratories that are not specifically equipped for tissue culture work.

Adolescent↗
PubMed1981

Case report. The pathogenesis of neurovascular complications following penicillin injection.

A 12-year-old patient presented following inadvertent intraarterial injection of benzathine penicillin. Complications manifested as an incomplete cauda equina lesion with ischaemia and necrosis over the buttock in the distribution of the injected artery. Angiography confirmed damage to the superior gluteal artery while histology revealed severe ischaemic damage without evidence of an allergic process. Spasm of the injected vessel with retrograde flow and occlusion by particulate matter can explain the clinical manifestations. The prognosis for these complications is poor and the best approach lies in prevention.

Arteries↗
PubMed1981

The effect of age and sex on bone density, bone mineral content and cortical index.

The density of cancellous bone in the nondominant radius of healthy subjects has been observed by the Compton scattering method as a function of age and sex. The average density for males is higher than for females. In males the density does not change up to the age of 80 years, while in females the density decreases beginning at age 50. A significant decrease in the bone mineral content of the distal radius is observed at earlier ages as measured by the Cameron-Sorenson technique. The average value of the cortical index of the third metacarpal shows some difference between the sexes over the age of 50, the index in males being higher than in the females. Between 30 and 50 years the female cortical index is greater than in the males. Little correlation was found among the three parameters studied, suggesting that they measure different phases of the pathophysiological processes involved in aging bone.

Adult↗
PubMed1980

Thick filament size changes in contraction of human muscles.

Measurements done on electron micrographs shows that in myofibres with sarcomeres contracted to below 2.1 micron, proportional shortening of the A bands occurs. In muscles from patients with idiopathic scoliosis very short A bands are especially prominent.

Cytoskeleton↗
PubMed1980

Microanalysis and X-ray fluorescence spectrometry of platelets in diseases with elevated muscle calcium.

Electron microscopic X-ray microanalysis and X-ray fluorescence spectrometry were done on platelets from patients with Duchenne muscular dystrophy and idiopathic scoliosis (both these conditions are known to be associated with increased intramyofibre calcium). A significant increase in calcium and phosphorus concentrations was found in the dense granules and whole cells of both conditions. The findings suggest that idiopathic scoliosis like Duchenne muscular dystrophy is a multisystem disease with detectable changes in platelets.

Adolescent↗
PubMed1980

Platelet pathology in patients with idiopathic scoliosis: Ultrastructural morphometry, agrregations, x-ray spectrometry, and biochemical analysis.

The fundamental similarity between platelets and muscle, suggested the possiblity of a shared defect in idiopathic scoliosis, a genetic disease with lateral deformity of the spine in which there is an elevation of calicum concentration in muscles and platelets. A variety of platelet tests revealed the following abnormalities: (1) Electron microscopic x-ray analysis and x-ray fluorescence spectrometry showed a 2- to 3-fold increase in calcium and phosphorus in whole cells and in individual dense bodies. (2) Electron microscopy morphometry revealed an increase in electron-opaque bodies in air-dried cells; granules and microtubules were unchanged. There were more large cells and membranous complexes. (3) Aggregations with epinephrine and ADP were depressed in some patients. (4) Proteins (total and contractile) and myosin. ATPase activity in centrifuged fractions of platelets were decreased in the cytosol and increased in the fraction containing membranes and granules. The correlated findings suggest that platelets in idiopathic scoliosis have a mild calcium transport defect related to membrane and/or contractile protein metabolism. This investigation also shows that platelets may be used to advantage in diagnosis and research of muscle diseases.

Actins↗
PubMed1979

Early fibular bypass procedures (tibiofibular synostosis) for massive bone loss in war injuries.

The techniques of fibular bypass grafting for massive tibial bone loss have been well described over the past 50 years. These techniques have generally been used as salvage procedures in post-traumatic civilian patients with chronic sepsis, or for congenital pseudoarthrosis. We present the experience of the Orthopaedic Department of the Hadassah University Hospital in successfully treating massive tibial bone loss by early fibular bypass grafting in four war injuries, where such definitive procedures would have been avoided in the past.

Adolescent↗
PubMed1979

Muscle pathology in idiopathic scoliosis.

Muscles from patients with scoliosis were studied to determine the possible relationship between neuromuscular disease and idiopathic scoliosis. Biopsies taken from the paraspinal musculature, the gluteus maximus and other sites were examined and compared with control specimens taken from patients undergoing spinal surgery for other disorders. Morphological and morphometric examinations by light and electron microscopy revealed a wide range of pathological changes and an alteration in the normal distribution of fiber types in most muscles. Changes were mainly nonspecific, but one unusual feature in idiopathic scoliosis but not in the other types of scoliosis consisted of type I fiber atrophy in paraspinal and deltoid muscles of the concave side paraspinal muscle, the site of the maximum morphological changes. The localized muscle changes, which are disease and not deformity related, suggest that idiopathic scoliosis is a separate disease entity and that the central nervous system may be involved in its genesis.

Adolescent↗
PubMed1978

X-ray fluorescence analysis of muscles in scoliosis.

X-ray fluorescence spectrometry was used to determine calcium, copper, and zinc concentrations in paraspinal and gluteal muscles obtained during spinal surgery from patients with scoliosis. Samples of 1-3 mg were sufficient to demonstrate that calcium was higher in idiopathic than in other forms of scoliosis or in normal control muscles. It is suggested that a calcium-related neuromuscular defect could be an important factor in the genesis of idiopathic scoliosis.

Calcium↗
PubMed1977

The early detection of osteoporosis by Compton gamma ray spectroscopy.

The density of the distal end of the radius is one of the parameters used to determine the presence and degree of osteoporosis in patients. In this work the bone density has been determined by measuring the intensity of the Compton scattered photons, since this is proportional to the absolute density of the scatterer, in materials for which Z/A is constant. A collimated beam from a 500 mCi 137Cs source was used and the intensity of the scattered radiation measured at an angle of 90 degrees. The exact point of measurement was determined by a two-dimensional scanning technique. A plastic water phantom was used to calculate the correction needed for absorption and backscatter by the surrounding tissue. Bone density was measured by this method in 50 subjects. A good correlation was found between density of the radius and the degree of morphological change in the vertebrae. In a number of cases a low bone density was discovered without signs of osteoporosis in the spine. These findings were considered indicative of early osteoporotic change, not definable by routine X-ray techniques. This technique may be of value in the follow-up of patients and in controlling the effect of various treatment schedules.

Aged↗
PubMed1977

Open reduction of unstable thoracolumbar spinal injuries and fixation with Harrington rods.

The results of treatment of sixteen patients with unstable thoracolumbar spinal injuries are recorded. Early open reduction, stabilization with Harrington rods, spine fusion, application of a plaster jacket until consolidation, and early mobilization was the treatment. Distraction rods were used in twelve patients and compression rods, in four. Nine patients with incomplete paraplegia showed marked neurological recovery, while five with complete paraplegia regained only some sensation. Two patients had no neurological involvement. Solid fusion was achieved in fifteen patients after a minimum of three months of plaster-cast immobilization. In one patient stabilization failed. There was a loss of 5 degrees on average (range, 2 to 23 degrees) in the correction of the kyphosis. Lateral angulation after surgery did not occur. The treatment allowed easier postoperative nursing and early mobilization of the patient.

Adolescent↗
PubMed1976

Spread of gold injected into the joints of healthy rabbits.

This study shows that after intra-articular injection, aurothiomalate and colloidal gold of small (200 A) particle size were rapidly absorbed from joints while the larger, 300 A, particle size colloidal radioactive gold could not be found outside them. Larger particle size suspensions seem therefore more likely to remain localised in the joint and its lining synovium after intra-articular injection, the systemic absorption from the joint cavity diminishing with increasing particle size. It was also found that the intra-articular injection of small amounts of aurothiomalate, of colloidal gold and of colloidal radioactive gold produces identical degenerative lesions in the lining cells of the proximal convoluted tubules of the kidneys. These lesions were always found, although gold particles were demonstrated only in sampled kidney tissues of the animals injected with the soluble gold preparation whereas no gold could be detected in the tissues of animals injected with colloidal non-radioactive or radioactive gold. Electron microscopic evidence is presented to suggest the possibility that the mitochondria are the "target" organelles of the gold-induced cellular damage. Mitochondrial damage was demonstrated in liver and spleen in addition to the already described kidney damage. The correlation between structure and function of the mitochondrial changes is not clear, and ionic shifts may be both a cause and a result of damage.

Animals↗