Short-term fixation

Besides the CHARITfi, the ProDisc has the second-longest clinical follow-up of any currently available artificial disc design [34]. Mamay implanted 93 first-generation, ProDisc 1 artificial discs in 64 patients between March 1990 and September 1993 [34, 35]. The endplates of the ProDisc 1 were fabricated from Ti alloy (Figure 12.6A). Each endplate featured two short, parallel keels for short-term fixation, and the back surfaces were plasma sprayed with titanium for bone ongrowth. 

Fixation procedures are necessary when biohazardous samples are analyzed, and are sometimes used to allow access of membrane impermeant fluorochromes, or to stabilize samples for short-term storage. Optimal fixatives are those that have low autofluorescence and do not significantly affect staining. Paraformaldehyde, at concentrations of 0.5-2%, and ethanol (70%, 4 C) are widely used fixatives for flow cytometry. Combinations of paraformaldehyde with Triton X-100 or saponin have been employed in procedures that fix and permeabilize cells. 

Apart from antibodies detected by (a) the schizont-infected red cell agglutination test, (b) the agglutination of sporozoites, (c) complement fixation, (d) passive hemagglutination and by the direct and indirect immunofluorescent methods [for review, see reference (V4)], malarial antibodies have also been detected by malarial antigens prepared from heavily infected human placenta, infected human brain, and short-term in vivo cultures of cells from heavily parasitized subjects (Wll) (see Tables 7 and 8). 

BrdU/DNA flow cytometry offers flexibility and diversity in the study of cell kinetics from cells in culture to human tumors in vivo. The essence of the procedure is to pulse label with BrdU by a short-term incubation in vitro or by a single injection in vivo samples are then taken at time intervals thereafter and stained after fixation in ethanol. The cells are then stained with a monoclonal antibody against BrdU that can be either directly conjugated to a fluoro-chrome (usually fluorescein isothiocyanate [FITC]) or, alternatively, bound to a second antibody conjugated with FITC. The cells are then counterstained with propidium iodide (PI) to measure the DNA content and analyzed on the flow cytometer. The results are displayed as linear-red fluorescence on the x-axis vs linear or log-green fluorescence on they-axis. 

In 2003, an up-to-date summary of studies was edited by Epinette and Manley (2003), describing the state-of-the-art of hydroxyapatite coatings in orthopaedics as this stood at the close of 2002. This compilation of results was designed to help to answer the still somewhat hotly debated question of whether the favourable results achieved in the short term with this method of biologic fixation of total joint implants has withstood the test of time. The goal of Epinette and Manley s book was mainly to determine if the use of hydroxyapatite coatings for the fixation of orthopaedic implants to bone has been proven by the survivorship and satisfaction of those patients who had received hip and knee implants. 

Hetherington VJ, Lord CE and Brown SA (1995) Mechanical and histological fixation of hydroxylapatite-coated pyrolytic carbon and titanium alloy implants a report of short-term results. 

Computer Simulation. To determine what conditions might, be required to produce a negative P vs. Q relationship, a simulation model of C3 photoi thesis (JMC) was employed which essentially used the carbon fixation and photochemistry equations of Farquhar et al. (5) and the stomatal response equations of Jarvis (6). Based on that analysis, an adjustment of carbo lation efficiency was implicated in the short term control of photoi thesis as follows ... 

The short-term recovery of P supplied in fertilisers is generally not high and up to 85% may be irrecoverable (phosphate fixation). Comparatively little of the P is leached and lost by drainage or surface run-off - it is mostly converted to the insoluble compounds listed in Table 12.8. Most of the phosphorus in these compounds is not immediately available to the plant, and as already stated, it is usually necessary to add more fertiliser than the amount taken up by the crop. No more than about 25% of the added P is likely to be taken up by the crop during the first year. The excess tends to accumulate as the insoluble compounds (fixed P), thus increasing the unavailable P content of the soil. 

The carboxylation of ribulose diphosphate is not the only pathway for the entry of carbon dioxide into plant metabolism. The finding of C -labeled malic acid in short-term photosynthesis suggests another pathway. This may be related to the reaction described by Bandurski and Greiner 60) where phosphoryl-enolpyruvate was carboxylated to yield oxal-acetate. Pathways of carbon dioxide fixation known to occur in other organisms 3) may be present in plants under special conditions. The relative importance of the various pathways depends on a number of factors species of plant, age of plant, part of plant examined, growth conditions, experimental conditions, and others. 

The duration of de-masking should be prolonged if material is over fixed or in the case of high formaldehyde concentration (over 5 %) in the fixative used. In contrast, to obtain comparable results, reducing the time of de-masking is necessary if short-term (up to 24 h) fixation in zinc-containing aldehyde fixatives or fixation in the Carnoy solution is used. 

In this report we have studied the short term affects of glutaraldehyde fixation on coupling factor activity and light induced conformational changes.Adopting the protocoil of Dilley and coworkers,we have terminated the glutaraldehyde treatment by the addition of an excess of free amine buffer.By this procedure treatment times as short as 5s could be reproduce ibly carried out. 

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