Occlusion time

Santerre and collaborators [72,73] also found that the plasma interaction of polyether urethanes was significantly altered by incorporation of sulfonate groups [73] which could be derivatized with amino adds [72]. The synergistic effect of pendant PEO and sulfonate groups grafted onto polyurethanes resulted in prolonged ex vivo occlusion times [482]. These results corresponded well with... 

Figure 4.13 shows a rat brain undergoing 90-min occlusion of the MCA. It exhibits an initial diffusion abnormality that resolves nearly completely after reperfusion. At shorter occlusion times, the ADC is known to normalize throughout the entire brain. Interestingly, several hours up to 3 days after reperfusion of a mild ischemic insult, the lesion may reappear and, eventually, evolve into brain... 

Occlusion time (min) = time to zero blood flow... 

Percent change in mean values for occlusion time and thrombus size in drug-treated groups is compared to the control group. 

Mean values of occlusion times (min) in dosage and control groups are calculated and compared by means of the t-test. 

Time until occlusion (time after restoring of vessel blood flow until occlusion of the vessel indicated by a flow less than 3.0 ml/min)... 

The in vivo efficacy of the bifunctional thrombin inhibitors 4 and 7 was also assessed in a chemically-induced thrombosis model where deep arterial injury to the rat carotid artery is mediated by FeCb [79]. Stenosis of the blood vessel resulting from FeCb-mediated injury results in decreased blood flow and an abrupt temperature drop across the stenosed area due to arterial occlusion. Both bifunctional thrombin inhibitors 4 and 7 doubled the mean occlusion time (MOT) at an i.v. bolus dose of 1 mg/kg. At a dose of 2 mg/kg i.v. of compound 7, the vessel remained patent for over 60 minutes compared to saline treated control rats (MOT = 19 1 minute), r-hirudin was slightly more potent, doubling the mean occlusion time at an i.v. dose of 0.5 mg/kg. 

Mean occlusion time (MOT) in saline treated animals is 19 1 min. All drugs were administered by the intravenous route. 

Bacterial occlusion time Test product Inoculation immediately after final wash Inoculation 24 hours after final wash ... 

The chamber test is a routine method of patch testing for contact allergy, but it can also be used to study NIICRs. The test substances are applied in small aluminum chambers (Finn Chamber, Epitest Ltd, Hyryla, Finland) and fixed to the skin with porous acrylic tape. The occlusion time is 15 min and the test is read at 20, 40 and 60 min. Occlusion enhances percutaneous penetration and may increase the sensitivity of the test. The advantage of the chamber test is that a smaller skin area is needed than in the open test (Lahti 1980 Hannuksela 1995). 

As Table 5 reveals, occlusion takes place within 20-30 min with the formation of clots when the ungrafted PE tubes are anastomosed with the rat carotid. Graft co-polymerization with AA is virtually not able to prolong the occlusion time. In contrast to the PRP experiment, neutralization of AA chains with NaOH does not improve the blood compatibility when the test is performed with flowing blood. On the other... 

In a patient presenting with symptoms of an acute arterial occlusion, time is critical. If the limb is threatened on physical exam, the patient should proceed to angiography/surgery without noninvasive testing. In a nonthreatened limb with suspected occlusion, ABIs can be performed along with a duplex scan. A duplex scan can help to identify the source of occlusion or confirm a thrombotic event, such as in the territory of a peripheral aneurysm or a stenosis (Fig. 5). 

---