Platelet index

Such difficulties prompted research workers to look for some other index of NT function in humans. These range from studies on platelets, such as abnormalities in their amine uptake and MAO activity in depressed patients, to changes in the secretion of a hormone known to be controlled by a particular NT. Thus if NA controls growth hormone release, and the secretion of the hormone is changed in depressed patients, does that confirm a role for NA in the mediation of depression ... 

Colorants have been developed for special effects. Pearlescent or iridescent give an attractive appearance. They are often used for coating paper (e.g., cosmetic packaging). The pigment consists of thin platelets, less than 1 pm thickness, which have a high refractive index, e.g., mica coated with Ti02. 

To date, there have only been a limited number of studies directly examining PKC in bipolar disorders [77], Although undoubtedly an oversimplification, particulate (membrane) PKC is sometimes viewed as the more active form of PKC, and thus an examination of the subcellular partitioning of this enzyme can be used as an index of the degree of activation. Friedman etal. [78] investigated PKC activity and PKC translocation in response to serotonin in platelets obtained from bipolar-disorder patients before and during lithium treatment. They reported that the ratios of platelet-membrane-bound to cytosolic PKC activities were elevated in the manic patients. In addition, serotonin-elicited platelet PKC translocation was found to be enhanced in those patients. With respect to brain tissue, Wang and Friedman [74] measured PKC isozyme levels, activity and translocation in postmortem brain tissue from patients with bipolar disorder, and reported increased PKC activity and translocation in the brains of bipolar patients compared with controls, effects which were accompanied by elevated levels of selected PKC isozymes in cortices of bipolar disorder patients. 

Microdiffraction patterns are taken from individual particles after the reduction treatment and are shown in Figs. 3a-d. Most particles with platelet shape and straight edges produce similar microdiffraction patterns, one of which is shown in Fig. 3a. It is indexed as PtsSi with CusAu structure on [100] zone axis. Figs. 3b and 3c show the diffraction patterns from the not reacted Pt on [100] and [310] zone axes, respectively. Particles with irregular forms show various diffractions and a considerable amount of them can be attributed to Pt Sis. One such pattern is shown in Fig. 3d, exhibiting Pt Sis on [152] zone axis. 

Therapy, to be effective, depends upon administration of an adequate number of platelets, generally 5 X 10 in a 70 kg man or a 60 kg woman given over 15 minutes - with suitable adjustment for body surface area in children. It is mandatory that the increment is calculated and the duration of response be documented at 24 hours. The optimum practice is to relate the number infused to changes achieved in the patient by means of the corrected count index. This step anticipates the emergence of resistance that limits the value of repeated transfusions. Occasional allergic reactions have to be blocked by premedication with an intravenous injection 100 mg of hydrocortisone, 12.5 mg of phenergan and 1 g of paracetamol... 

Fig. 8. R/Platelet in individual platelets adhering to polymer surfaces. HSB data were statistically confirmed to be different from PSt (P < 0.5), HSR (P < 0.5) and PHEMA (P < 0.5) after 40 s R/Platelet (an index of cytoplasmic free calcium concentration) is the ratio of fluorescence emission intensitie of a Ca2 + indicator dye (Fura 2) loaded in platelets when they are excited at 340 nm and 380 nm. (Reproduced from J Biomed Mater Res [Ref 84 Prevention of changes in platelet cytoplasmic free calcium levels by interaction with 2-hydroxyethyl methacrylate/styrene block copolymer surfaces] through the courtesy of John Wiley Sons, Inc.)...

In practice, platelet crystals are synthesized with a layer thickness d calculated to produce the desired interference colors (iridescence) [5.206], [5.207], Most nacreous pigments now consist of at least three layers of two materials with different refractive indices (Fig. 73). Thin flakes (thickness ca. 500 nm) of a material with a low refractive index (mica) are coated with a highly refractive metal oxide (e.g., Ti02, layer thickness ca. 50-150 nm). This results in particles with four interfaces that constitute a more complicated but still predictable thin film system. The behavior of more... 

Under appropriate reaction conditions, regular hexagonal platelets (ca. 50 nm thick and 20 pm in diameter) can be obtained. The high refractive index (n — 2.0), high aspect ratio (> 200), and the extremely even surface of basic lead carbonate make it an optical match to natural pearl essence. 

Iron Oxide-Mica. Iron(III) oxide is suitable, like titanium dioxide, for coating of mica platelets. It combines a high refractive index (metallic luster) with good hiding power and weather resistance. 

Many of the thinner platelets are transparent and a rich ruby-red color in transmission. They give a uniaxial negative interference figure. The crystals are too deeply colored for refractive index determination, but the mean value is greater than 2. 

Grotemeyer 180 Stroke 1500 1 yr Platelet reactivity Normal PR index 33.3 40% of AR... 

It has been shown that patients with diabetes exhibit platelet activation and increased reactivity to agonists. The heightened platelet reactivity may be related to the increased prevalence of nonresponders and occurrence of ischemic events reported in patients with diabetes (106,107). It has also been reported that patients with a high body mass index (BMI) exhibited a suboptimal platelet response with the standard 300 mg loading dose (108). 

---