Search results for "synthesis"
showing 10 items of 2844 documents
Minimally invasive plate fixation in femoral shaft fractures
1997
Bridge-plating with its advantages in terms of vascularity and bone healing is a well established procedure today in the treatment of comminuted femoral fractures. Bridge-plating means that the fracture site is not interfered with during the operative procedure. This paper introduces a surgical technique in which the plate is inserted through isolated proximal and distal incisions only, behind the vastus lateralis. Alignment is secured by the plates, the fracture site remains untouched, fixation and screw insertion is restricted to the proximal and distal main fragments. Longitudinal femoral fractures extending right into the trochanteric and or condylar areas are the main indication for mi…
The Homeostasis of Brain Choline
1993
The interest in the homeostasis of brain choline is reinforced by the role of choline as immediate precursor of acetylcholine, phosphatidylcholine and other phospholipids in the brain. In order to obtain a comprehensive view of the mochanisms of homeostasis it appeared necessary to elucidate the negative arteriovenous difference of choline across the brain (net release), a phenomenon that has been known for 20 years and is present in mammals and in man. This finding prompted an intense search for a de novo synthesis of choline in the brain. We detected in anaesthetized rats a reversal of the net release into a net uptake (positive arterio-venous difference), when the plasma level of choline…
Alterations of DNA-dependent DNA polymerase activities in the immature quail oviduct in response to estrogen stimulation.
1975
Administration of diethylstilbestrol, an estrogen analogue, to immature female quails causes an increase of extractable DNA-dependent DNA polymerase activities from the oviduct. At least two forms of polymerases have been determined, a high molecular weight polymerase (210,000 daltons) and a low molecular weight polymerase (34,000 daltons) calculated from column chromatography Sephadex G-200. During the primary hormone stimulation the amount of extractable enzyme reaches a maximum on the fifth day after daily injections of the hormone. In the period of withdrawal the activities decrease and reach values similar to those determined in the unstimulated oviducts. During secondary stimulation t…
Biological activity of 2-phenylethanol and its derivatives
1973
The biosynthesis of herpesvirus DNA in rabbit kidney cells is inhibited to 50% by PEA (2-Phenylethanol) at 0.65 mg PEA/ml. The inhibition of cellular DNA synthesis in uninfected cells by PEA is about twice as sensitive as that of viral DNA synthesis.
Potential involvement of fas and its ligand in the pathogenesis of Hashimoto's thyroiditis
1997
The mechanisms responsible for thyrocyte destruction in Hashimoto's thyroiditis (HT) are poorly understood. Thyrocytes from HT glands, but not from nonautoimmune thyroids, expressed Fas. Interleukin-1β (IL-1β), abundantly produced in HT glands, induced Fas expression in normal thyrocytes, and cross-linking of Fas resulted in massive thyrocyte apoptosis. The ligand for Fas (FasL) was shown to be constitutively expressed both in normal and HT thyrocytes and was able to kill Fas-sensitive targets. Exposure to IL-1β induced thyrocyte apoptosis, which was prevented by antibodies that block Fas, suggesting that IL-1β-induced Fas expression serves as a limiting factor for thyrocyte destruction. Th…
A biomechanical evaluation of methods of distal humerus fracture fixation using locking compression plates versus conventional reconstruction plates.
2004
OBJECTIVES To examine the biomechanical behavior of 2 techniques of double-plate osteosynthesis for fractures of the adult distal humerus using conventional reconstruction plates and locking compression plates. DESIGN Basic science study. SETTING Experimental in vitro study. PATIENTS/PARTICIPANTS Forty fresh-frozen human distal humeri specimens. INTERVENTION Four matched groups with 10 humeri each, median age 74 years (46-95), were created using similar bone mineral density values. Two standard configurations of double-plate osteosynthesis (dorsal or 90 degrees configuration) with either conventional reconstruction plates or locking compression plates were studied for biomechanical properti…
Selenoprotein synthesis and side-effects of statins.
2004
Statins are possibly the most effective drugs for the prevention and treatment of hypercholesterolaemia and coronary heart disease. They are generally well tolerated, however, they do cause some unusual side-effects with potentially severe consequences, most prominently myopathy or rhabdomyolysis and polyneuropathy. We noted that the pattern of side-effects associated with statins resembles the pathology of selenium deficiency, and postulated that the mechanism lay in a well established, but often overlooked, biochemical pathway--the isopentenylation of selenocysteine-tRNA([Ser]Sec). A negative effect of statins on selenoprotein synthesis does seem to explain many of the enigmatic effects a…
Inhibition of ovarian steroidogenesis by cyclic-GMP in a fly
2003
1479-6805 0022-0795; Previous investigations in the female blowfly Phormia regina have shown that 3-isobutyl-1-methylxanthine (IBMX), a broad spectrum inhibitor of phosphodiesterases (PDEs), fails to mimic the steroidogenic effects of cAMP on ovaries, although it efficiently increases the concentrations of this second messenger. In this study, experiments carried out to clear up this contradiction demonstrated that IBMX, besides its effect on cAMP, also increased cGMP concentrations in blowfly ovary and that these two cyclic nucleotides controlled ovarian steroidogenesis antagonistically. In particular, a selective inhibitor of cGMP-specific PDEs, unlike IBMX, had a very strong negative eff…
Insulin synthesis in chick embryo retinas during development.
1994
Retinas of chick embryos contain insulin (1) and further, are capable of synthesizing it, as demonstrated by incubating retinas at different ages (7th–18th day) with [3H]leucine. The synthesized radioactive insulin was isolated and assayed by means of a HPLC procedure. The synthesis of insulin was found to be highest in the youngest retinas studied (day 7), afterwards it declined with age except for an increment found at 14–15 day. Explants of chick embryo retinas, cultured in vitro, rapidly degraded insulin. Nevertheless, the content of immunoreactive insulin in retinal explants diminished slowly with the age of culture, so that, after 8 days of incubation, it was about 60% of the content …
Effect of oral glutathione on hepatic glutathione levels in rats and mice
1989
Administration of oral glutathione (GSH) increases hepatic GSH levels in fasted rats, in mice treated with GSH depletors such as diethyl maleate and in mice treated with high doses of paracetamol. An increase in hepatic GSH levels after administration of oral GSH does not occur in animals treated with buthionine sulphoximine, an inhibitor of GSH synthesis. Administration of oral GSH leads to an increase in the concentration of l-cysteine, a precursor of GSH, in portal blood plasma. Oral administration of l-methionine produced a significant decrease of hepatic ATP in fasted rats, but not in fed rats. Administration ofN−acetylcysteine or GSH did not affect the hepatic ATP levels. The results …