Fibrous dysplasia

Fibrous dysplasia provides the orthopedic surgeon with tremendous reconstructive challenges. The manifestations of the condition are very diverse and often involve organ systems not routinely cared for by the orthopedic surgeon. We present a concise review of the radiography, histology, clinical manifestations, and complications of this condition, with the main focus on the non-orthopedic management challenges.     

The relationship of the theophylline concentration in the saliva and the blood serum in patients with a broncho-obstructive syndrome

Theophylline salivary and serum concentrations (Tser and Tsal) were quantified after a single dose administration of theophylline drugs: euphylline (2.4% solution, 10 ml i.v. jet and 0.15 orally), theo-dur, retaphil, theopek, theobilong (0.3 g orally). The drugs were given to patients with broncho-obstructive syndrome. The samples were obtained within 6 and 24 hours upon administration for euphylline and other drugs, respectively. Tser and Tsal were determined at high-performance liquid chromatography. The authors revealed a linear relationship between Tser and Tsal in different time intervals. The percentage factors and formulas of Tser calculation by its Tsal values have been estimated.     

Head-scatter factors in rectangular photon fields

Head-scatter factors were measured for a range of field sizes of rectangular shape from a linear accelerator that provides 6 and 25 MV photon beams. For a given field length and width, exchange of the inner and outer collimator pairs produces differences in the head-scatter factor of up to about 2% and 3% in open and wedged fields, respectively. Dependence on elongation deviates by up to 2% from that given by the equivalent squares. Such effects can easily be taken into account by using head-scatter data that have been directly measured in rectangular fields or by applying empirical corrections to values for square or equivalent square fields.     

Protein kinase CK2: biphasic kinetics with peptide substrates

1. The human umbilical vein has been found to contract in response to bradykinin (BK) and desArg9BK. 2. The rank order of potency of agonists, in the presence of the B1 receptor antagonist Lys[Leu8]desArg9BK, is as follows: [Hyp3, Tyr(Me)8]BK (pD2 8.88) = [Hyp3]BK (pD2 8.86) = LysBK (pD2 8.81) > or = BK (pD2 8.60) > [Aib7]BK (pD2 6.38) > desArg9BK and LysdesArg9BK (inactive). 3. Hoe 140 (pA2 8.42) inhibits the effects of BK while other B2 receptor peptide antagonists are very weak and WIN 64338 is practically inactive. 4. Venoconstrictor responses to desArg9BK of fresh tissues increase with time during the in vitro incubation and reach a maximum after 4-6 h. The activity of Hoe 140 (pA2 5.48) is negligible against B1 receptor agonists. 5. When measured in the presence of the selective B2 receptor antagonist Hoe 140 (400 nM), the order of potency of kinin related peptides on the B1 receptor is Lys[desArg9]BK (pD2 8.60) > desArg9BK (pD2 6.69). BK, LysBK, [Hyp3]BK and other B2 receptor agonists are inactive. 6. The B1 receptor antagonist, Lys[Leu8]desArg9BK (pA2 7.99), inhibits the response of the human vein to B1 receptor agonists (LysdesArg9BK or desArg9BK), but do not alter the effect of BK. 7. The results summarized in this paper indicate that the human isolated umbilical vein is a sensitive preparation containing both B1 and B2 receptors. The human B2 receptor shows some similarity with that of the rabbit (at least for agonist potencies) and differs from the B2 receptor of the guinea-pig. Compared to the rabbit B1 receptor, the human B1 receptor shows low sensitivity to peptides that lack the N-terminal Lys.     

Identification and partial characterization of a proteinase specific for insulin-like growth factor binding protein-3 in aqueous and vitreous humors

The IGFs (-I and -II) are normally found in serum and other extracellular fluids complexed to specific binding proteins (IGFBPs). While several IGFBPs have been identified in vitreous and aqueous humors, the major serum carrier of IGF, IGFBP-3, is notably absent from these fluids. To determine if this paucity could be due to an IGFBP-3 proteinase (IGFBP-3ase), samples of bovine vitreous or aqueous humor were mixed with serum and incubated at 37 degrees C for 4 h followed by western ligand blotting. In these experiments, a distinct loss of the 46 kDa band representing IGFBP-3 was observed while other bands present at 35, 28 and 25 kDa were unaltered. The IGFBP-3ase activity is temperature sensitive, has a pH optimum of about 8.0 and is inhibited by EDTA. Acid treatment of serum to remove endogenously bound IGF does not affect the specificity or activity of the IGFBP-3 proteinase. Size exclusion chromatography of bovine aqueous indicates an approximate molecular weight of 260 kDa. Incubation of recombinant IGFBP-3 or serum with partially-purified IGFBP-3ase results in the appearance of low molecular weight fragments of approximately 30 kDa. These fragments are undetectable by western ligand blotting but are readily visualized using an IGFBP-3 specific antibody. Comparison of normal and diabetic vitreous humor reveals the presence of an increased amount of IGFBP-3 proteolytic fragments in the diabetic as compared to control. These findings indicate the presence of a IGFBP-3 proteinase in aqueous and vitreous humors that may be important in regulating ocular homeostasis.     

Parathyroidectomy reduces 25-hydroxyvitamin D3-1 alpha-hydroxylase activity in the hypocalcemic vitamin D-deficient chick

To test the hypothesis that in the vitamin D-deficient state the activity of 25-hydroxyvitamin D3-1 alpha-hydroxylase (25-OHD3-1 alpha-hydroxylase) is modulated by parathyroid hormone and the plasma concentration of phosphate only in the presence of small amounts of 1,25-dihydroxyvitamin D3 (or some other metabolite of vitamin D), we measured the activity of this enzyme 24 h after parathyroidectomy (PTX) in frankly hypocalcemic, vitamin D-deficient chicks that were not supplemented with vitamin D or one of its metabolites. The otherwise predictable complications of PTX in this metabolic setting (hypocalcemia of increasing severity, tetany, moribundity, and death) were prevented by continuous intravenous administration of calcium (as a solution of calcium chloride/calcium gluconate 1:1) through a catheter in the external jugular vein placed at the time of PTX. The findings were as follows: (a) The activity of 25-OHD3-1 alpha-hydroxylase was significantly less in the parathyroidectomized group than in the sham-operated control chicks (P less than 0.001). (b) The reductive effect of PTX on the activity of this enzyme was significantly attenuated when hypophosphatemia was increased in severity by administration of glucose. (c) In the post-PTX state the activity of 25-OHD3-1 alpha-hydroxylase and plasma concentration of phosphate were significantly, inversely related (P less than 0.001). (d) In the sham-operated control group the activity of this enzyme and the plasma concentration of phosphate were not significantly correlated. These findings indicate that in the vitamin D-deficient state, both circulating parathyroid hormone and the plasma concentration of phosphate can significantly modulate the activity of 25-OHD3-1 alpha-hydroxylase in the absence of vitamin D or its metabolites. The findings also suggest that in the vitamin D-deficient state the plasma concentration of phosphate modulates the activity of this enzyme only when the concentration of circulating parathyroid hormone is not increased.