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Biomedical subjects

M Post

Publications and source records attributed to M Post.

At least 199 records · Page 11Linked to original sources
PubMed1980

Total shoulder replacement with a constrained prosthesis.

Forty-three shoulder-joint replacements were performed in forty-two patients using a constrained joint. Twelve material failures were experienced in the first series of twenty-two shoulders and only two in the second, modified series (twenty-one shoulders). Loosening of the glenoid components was not encountered, although radiolucent lines have been observed about some of the components. A basic feature of the design was to allow dislocation of the metal head from its cup when excessive motion of the components is attempted by the patient and a specific torque is exceeded. A method of insertion and design considerations allowed us to achieve strong attachment between the metal glenoid and the scapula.

Adult↗
PubMed1979

Constrained total shoulder joint replacement: a critical review.

Constrained total shoulder replacement is a salvage procedure for the patient with disabling pain and a nonfunctioning rotator cuff mechanism. The results of pain relief have been gratifying. When active overhead motion is a goal of treatment a strong deltoid muscle is required. The rationale for fixing a fulcrum is to substitute for the loss of the rotator cuff mechanism that stabilizes the humeral or prosthetic head on the shallow glenoid. The best method of attachment for the glenoid component to an intact glenoid vault described herein has been found to be superior to other methods. In particular, the vault should not be mutilated. This is borne out by the clinical experience and laboratory testing that loosening or pull-out does not occur with an intact glenoid. Moreover, the attachment is stronger than the dry bone just medial to the vault where fracture always occurred through the suprascapular notch in laboratory tests. Although there may be good pain relief with this operation, active function still depends on residual deltoid muscle power wherein a poor deltoid will only allow passive motion. Moreover, the outcome of any shoulder operation still depends in large measure on the excellence of the postoperative rehabilitation program. Finally, other worthwhile shoulder operations should be given first consideration in order to serve the needs of individual patients.

Biomechanical Phenomena↗
PubMed1978

Biochemical effects of gum arabic, gum tragacanth, methylcellulose and carboxymethylcellulose-Na in rat heart and liver.

Repeated oral administration of commonly used suspending media, gum arabic, gum tragacanth, methylcellulose, and carboxymethylcellulose-Na to rats caused uncoupling of oxidative phosphorylation in liver and heart mitochondria and partial inhibition of mixed function oxidases of liver endoplasmic reticulum, as measured by 2-biphenylhydroxylation and 4-biphenylhydroxylation. There were considerable differences between the compounds with regard to potency and reversibility of these effects. Only methylcellulose at a concentration of 0.5% did not alter mitochondrial function and mixed function oxidases. It is recommended as suspending medium for the use in pharmacological and toxicological experiments.

Acacia↗
PubMed1975

Calcitonin inhibition of bone cell metabolism in vivo: an experimental study in dogs.

Calcitonin (CT) has been shown to act by decreasing the output of calcium from the bone, but the precise mechanism that brings about this change is still not fully understood. The present investigation was designed to study the effect of CT on the metablic activity of bone cells, utilizing changes in oxygen consumption and carbon dioxide production as indices of tissue metabolism. Arterio-venous gradients of calcium, inorganic phosphate, hydroxyproline, oxygen, carbon dioxide and hydrogen ions were studied across the canine femur. The results showed that the hypocalcemic action of CT was accompanied by a corresponding decrease in free hydroxyproline output from the bone, demonstrating that decreased bone resorption was responsible for the fall in plasma calcium levels. Reduced oxygen consumption and decreased carbon dioxide production by the bone showed that CT acted by inhibiting the metabolic activity of bone cells in vivo. It is speculated that CT may have acted by depressing mitochondrial respiration.

Animals↗
PubMed1975

Surgery in hemophilic patients.

Surgery in hemophilic patients was performed under proper factor-replacement therapy, and a wide variety of orthopaedic procedures (twenty-six in seventeen patients) were done with good results. There were no complications in any of the patients since the advent of concentrates in 1966. Multiple procedures under one anesthetic are recommended because the complications associated with repeated administration of blood substitutes are minimized.

Adolescent↗
PubMedDate not supplied

Pectoralis major transfer for winging of the scapula.

From November 1988 to July 1992 eight patients with painful, chronic, disabling winging of the scapula caused by isolated serratus anterior paralysis had pectoralis major muscle transfer extended by a fascia lata graft. Six men and two women were treated. Duration of symptoms ranged from 12 to 35 months. Seven patients had a positive result on electromyography. In addition, four patients had multidirectional instability of the shoulder on the side of the winging. The postoperative follow-up period ranged from 12 to 57 months (average 27.1 months). Excellent results were obtained in all patients. In addition, patients with associated multidirectional instability improved, and only one subsequently required additional shoulder surgery. The described method of coiling and suturing the donor graft is believed to account for the consistent results and absence of substantial complications. Pectoralis major muscle transfer extended by a fascia lata graft appears to be an excellent operation for correcting scapular winging.

Adolescent↗
PubMedDate not supplied

Inhibition of lung maturation by monoclonal antibodies against fibroblast-pneumonocyte factor.

Fetal lung maturation, especially the onset of surfactant formation by alveolar type II cells, seems to be regulated by endogenous fetal glucocorticoids. Recent studies suggest that glucocorticoids do not act directly on the type II cell but rather on the lung mesenchyme. In response to glucocorticoids, the mesenchyme produces and secretes a polypeptide, fibroblast-pneumonocyte factor, which in turn stimulates surfactant synthesis by the alveolar type II cell. We report here the generation of hybridomas secreting monoclonal antibodies to rat lung fibroblast-pneumonocyte factor. Two monoclonal antibodies studied in detail reduced the cortisol-stimulated synthesis of saturated phosphatidylcholine in organotypic cultures of fetal rat lung cells and blocked the stimulatory effect of fibroblast-pneumonocyte factor in type II cells from these cultures. When embryonic chicks were injected on day 15 of incubation with either monoclonal antibody, they showed on days 20 and 21 biochemical evidence of delayed lung maturation as compared with controls. These effects were organospecific. Our observations support a physiological role for fibroblast-pneumonocyte factor in prenatal lung maturation.

Animals↗