To evaluate the cerebral blood flow in feline hydrocephalic brain, this study was designed to measure the regional cerebral blood flow(rCBF;frontal and periventricular area) by the hydrogen clearance method in different stages of the kaolin-induced hydrocephalus and the postshunt status. The results were as follows: 1) A reduction of rCBF was detected in the left periventricular area at two weeks after kaolin injection. A significant reduction of rCBF was revealed in the left periventricular area at two and four weeks after kaolin injection. However, the rCBF of the left frontal cortex was significantly decreased at four weks after kaolin injection. 2) At one week after shunt operation, the significant restroration of rCBF was found in the left frontal cortex and the left periventricular area.
Brain ; Hydrocephalus* ; Hydrogen ; Kaolin

To study the effect of hydrocephalus and skull defect on the pressure volume index(PVI), PVI values were measured in 4 groups, total 23 cats. Five normal cats(group I : control group), five kaolin induced hydrocephalic cats(group II), six kaolin induced hydrocephalic cats with delayed hemicranicetony(group III) and seven kaolin induced hydrocephalic-hemicraniectomy cats(group IV) were used. In 4 groups, the effects of laterality of ventricular bolus infusion site, hydrocephalus and skull defect on the PVI values were evaluated. The measuremnets were performed 4 weeks after kaolin inhection in hydrocephalic groups(group II, III and IV). The laterality of ineusion site did not have satistically significant influence on the PVI valu in all 4 groups. Compared to group I, the PVI values in group II and III showed increasing tendency without significance. But in group IV, the PVI values showed statistically significant increase, and this seemed to be due to the biomechanical changes of brain and the more progressive ventricular enlargement by the combination of kaolin induced hydrocephalus and skull defect. As with above results, PVI values showed increasing tendency according to the degree of ventricular enlargement and the defect of skull.
Animals ; Brain ; Cats ; Hydrocephalus* ; Kaolin ; Skull*

BACKGROUND: High-dose aprotinin has been reported to enhance the anticoagulant effects of heparin during cardiopulmonary bypass ; hence, som authors have advocated reducing the dose of heparin in patients treated with aprotinin. MATERIAL AND METHOD: The ACT was measured before, during and after cardiopulmonary bypass, with Hemochron 801 system using two activators of celite (C-ACT) and kaolin (K-ACT) as surface activator. From June, 1996 to February, 1997, 22 adult patients who were scheduled for elective operation were enrolled in this study. RESULT: The ACT without heparin did not differ between C-ACT and K-ACT. At 30 minutes after anticoagulation with heparin and cardiopulmonary bypass, the average C-ACT was 928+/-400 s; K-ACT was 572+/-159s (p<0.05). After administration of protamine, C-ACT was 137+/-26 s; K-ACT was 139+/-28s, which were not statistically significant. CONCLUSION: Our results showed that the significant increase in the ACT during heparin-induced anticoagulation in the presence of aprotinin was due to the use of celite as surface activator, rather than due to enhanced anticoagulation of heparin by aprotinin. We conclude that the ACT measured with kaolin provides better monitoring of cardiac surgical patients treated with high dose aprotinin than does the ACT measured with celite. The patients treated with aprotinin should receive the usual doses of heparin.
Adult ; Aprotinin* ; Cardiopulmonary Bypass ; Diatomaceous Earth* ; Heparin ; Humans ; Kaolin*

To evaluate the biomechanical changes and cerebral blood flow in hydrocephalic brain, this study was designed to determine the regional cerebral blood flow(rCBF; frontal cortex and periventricular area), the pressure volume index(PVI) and the resistance to the absorption of cerebrospinal fluid(Ro) in different stages of the kaolin-induced hydrocephalus. Fifty five 8 week-old cats, weighing 900g to 1300g were used in this experiment. The experimental animals were divided into 2 groups ; a normal control(5 cats), and kaolin-induced hydrocephalic groups(50 cats). The kaolin-induced 1,2,4,6 and 8 weeks hydrocephalic groups after intracisternal injection of the kaolin. The rCBF was measured by hydrogen clearance technique and the PVI and Ro were determined by the technique of bolus manipulation of CSF. A significant elevation of the intracranial pressure(ICP) was observed in 2 weeks after kaolin injection and peak value(ICP=10.2+/-0.9mmhg) was obtained in 4 weeks after Kaolin injection. The significant decrease in rCBF were revealed in both frontal cortex and periventricular area of kaolin-induced hydrocephalic cats. The PVI was significantly increased from the normal value 0.77+/-0.02ml to 1.60+/-0.16ml at 4 weeks after kaolin injection and increased to 2.12+/-0.34ml at 6 weeks after kaolin injection. Ro was significantly decreased from the normal value 90.6+/-1.3mmHg/ml/min to 36.8+/-4.3mmHg/ml/min at 4 weeks after kaolin injection and further decreased to 6.2+/-1.9mmHg/ml/min at 8 weeks after kaolin injection. In Hydrocephalic cats, the size of the ventricle(septum pellucidum-caudate nucleus distance) continued to increase in size up to 9.40+/-0.7mm at the 4th week. However, there was no further increase in ventricular size after the 4th week. This study indicated that kaolin-induced hydrocephalic cats led to dramatic changes in volume-buffering capacity expressed as PVI, coupled a reduction in the Ro. The absorptive defect and also loss of volume-buffering capacity are not sufficient to cause progressive ventricular enlargement. It is assuming that some microcirculatory impairment in the brain parenchyma is playing an important role which facilitates ventricular expansion with changes of biomechanical property of the brain.
Absorption ; Animals ; Brain ; Cats ; Hydrocephalus* ; Hydrogen ; Kaolin ; Reference Values

We investigated the somatosensory evoked potentials(SEPs) changes and subsequent changes of the ventricular enlargement in different stages of kaolin-induced hydrocephalus. 8 week-old fifty five cats weighing 900g to 1300g, were studied in this experiment. These animals were divided into 2 groups ; a normal control(5 cats), kaolin-induced hydrocephalic groups(50 cats). The kaolin-induced hydrocephalic groups were subdivided into 5 subgroups of 10 cats each ; kaolin induced 1,2,4,6 and 8 weeks hydrocephalic groups after an intracisternal injection of the kaolin. At the each stage of the kaolin-induced hydrocephalic animals, the following parameters were obtained ; somatosensory evoked potentials(SEPs) and the size of enlargement of the ventricles at the each stage of 1,2,4,6 and 8 weeks after intracisternal kaolin injection. The results were as follows: 1) A significant elevation of the intracranial pressure(ICP) was observed in 2 weeks after kaolin injection and peak value(ICP : 10.2+/-0.9mmHg) in 4 weeks after kaolin injection. 2) The mean latencies of these wave components in somatosensory evoked potentials(SEPs) responses were 6.27+/-0.12 msec in Po, 8.41+/-0.25 msec in No, and 12.55+/-0.36 msec in P1 and the mean central conduction time(P1-P0) was 6.10+/-0.16 msec in the normal control animals. 3) Changes of amplitude and latency in SEPs were more prominent in 4 weeks after kaolin injection and progressively prolonged latencies of each wave components and CCT were resulted in 6 and 8 weeks after kaolin injection. 4) In hydrocephalic animals, the size of the ventricle(septum pellucidum (SP)-caudate nucleus(CN) distance) was moderately increased to 5.19+/-0.43mm in 1 week after kaolin injection and continued to increased in maximum size up in the 4th week after injection. However there was no further increase in ventricular size after 4th weeks. 5) A close correlation was found between SEPs and ventricular enlargement at the each stage of kaolin-induced hydrocephalic animals. In conclusion, it is assumed that the detection of SEPs in hydrocephalus is a quite valuable prognostic tool to evaluate the functional integrity of the nerve conduction system near the paraventricular area which might be involved in ventricular enlargement.
Animals ; Cats ; Evoked Potentials, Somatosensory* ; Hydrocephalus* ; Kaolin ; Neural Conduction

OBJECTIVETo isolate the bioflocculant-producing bacteria from activated sludge and investigate the flocculating characteristics of the newly isolated bioflocculant.

METHODSBacteria were screened from activated sludge samples to isolate bioflocculant-producing bacteria. Flocculating activity was used as a measure of the flocculating capability of the bioflocculant.

RESULTSA novel bioflocculant-producing bacterium was isolated, which was identified to belong to genus Aeromonas and named as Aeromonas sp. N11. Flocculating activity increased in the presence of K+, Na+, or Ca2+. The highest flocculating activities for kaolin suspension were obtained in acidic pH ranges, and optimum pHs for it were 3.0, 4.0, and 5.0 with 1 mmol/L K+, Ca+, and Na+ present, respectively. The highest flocculating activities for soil suspension were observed at pH 8.0. The bioflocculant had a good flocculating activity and could achieve a flocculating activity of 92.4% for kaolin suspension at a dosage of only 1 mgxL(-1), and its activity in kaolin suspension was decreased by only 9.2% after heating at 100 degrees C for 60 min.

CONCLUSIONThe bioflocculant produced by Aeromonas sp. N11 has strong flocculating activity and high stability, which affords high possibility of its practical use.

Residual heparin effects after protamine reversal is a potential bleeding disorder associated with cardiopulmonary bypass(CPB). To differentiate this from the other multiple factors causing coagulopathy should be initialized in the setting of management. The purpose of this study was to compare simple activated clotting time(ACT) and thromboelastography(TEG) with heparinase treated ACT and TEG for detecting residual heparin effects to distinguish rapidly the presence of heparin from the effects of other factors because the enzyme heparinase specifically neutralized heparin. After institution approval, 20 patients who required open heart surgery were studied. Baseline kaoline ACT, heparinase ACT, TEG and heparinase TEG(Haemoscope) were obtained before CPB on the same blood sample. The repeated tests were performed on the same blood samples 20 minutes after protamine reversal following CPB. Differences between heparinase treated tests and untreated tests were also evaluated at the same time. Wilcoxon signed ranked test was used to compare the results between before and after bypass. None of patients had significant postoperative bleeding complication. All tests before bypass were normal. Twenty minutes after protamine reversal, 3 patients showed kaoline ACT were extended above 10% of the value of heparinase ACT but all of them remained within normal range. However, nearly all patients showed heparin effects on TEG. The heparin effects on TEG were defined as significant differences in all of parameters, especially in alpha angle and R+K time between simple TEG and heparinase TEG. In Conclusion, heparinase treated ACT and native ACT are not sensitive to residual heparin effects after CPB. Their normal results did not preclude residual heparin effects on heparinase modified TEG. However, it might be further investigated to need additional protamine in the case of residual heparin effects on TEG.
Cardiopulmonary Bypass* ; Hemorrhage ; Heparin Lyase* ; Heparin* ; Humans ; Kaolin ; Reference Values ; Thoracic Surgery ; Thrombelastography*

To evaluate the cerebral blood flow in feline hydrocephalic brain, this study was designed to measure the regional cerebral blood flow(rCBF ; frontal and periventricular area) by the hydrogen clearance method and to visualize the vascular morphology such as angioarchitecture, diameter and number of vessels using microfil in different stages of the kaolininduced hydrocephalus. There have been several prior reports about intracraial vascular morphology, using various material such as colloida carbon and microcorrosion casts. But there is none about microfil in normal or hydrocephalic cats. The authors made a first cicrofil model to observe the vascular changes in experimental feline hydrocephalus in the literature. The results were as follows : 1) A reduction of rCBF was detected in the left periventricular area at 2 weeks after kaolin injection. A significant reduction of rCBF was revealed at left periventricular area at 4 weeks after kaolin injection. However, the rCBF of the left frontal cortex was significantly decreased at 4 week after kaolin injection. 2) A reduction in diameter of vessels was detected in the left periventricular area at 2 weeks after kaolin injection. The significant reduction of diameter in the left periventricular area was revealed at 4 weeks after kaolin injection. 3) The vessels of the periventricular area in the control cats were dense but loose in hydrocephalic cats. A reduction in number of vessels was found in the a periventricular area at 1 week after kaolin injection. A reduction in number of vessels was found at 2 weeks after kaolin injection also. And a significant reduction in number of vessels was found at 4 weeks after kaolin injection. 4) The number and caliber of vessels in the frontal cortex were similar between the control and hydrocephelic groups. However, cortical vessels of the control group were straight and parallel and showed the typical 'palisade pattern', whereas some of the hydrocephalic group showed distortion of the cortical vessels. In conclusion, ventricular enlargement causes displacement of primary cerebral arteries, followed by both stretching and a decrease in the caliber of the microvasculature, resulting in diminished cerebral blood flow and tissue destruction. The results suggest that vascular changes playa important role in the production of brain damage in hydrocephalus.
Animals ; Brain ; Carbon ; Cats ; Cerebral Arteries ; Hydrocephalus* ; Hydrogen ; Kaolin ; Microvessels ; Silicone Elastomers

BACKGROUND: High-dose aprotinin appears to enhance the anticoagulant effects of heparin, as documented by increases in the activated clotting times (ACTs) during cardiopulmonary bypass. This increase of the ACT in the presence of aprotinin and heparin is due to the use of celite as surface activator. We compared celite and kaolin as surface activators for the measurement of the ACT in cardiac surgical patients treated with high dose aprotinin. METHODS: This study included 25 patients who were scheduled for coronary bypass graft surgery and reoperation of cardiac valvular surgery. The 2 million units of aprotinin were added to the pump prime of heart-lung machine. The dosage of heparin and protamine was 3 mg/kg respectively. Whole blood was sampled 10 minutes after induction, heparin administration, cardiopulmonary bypass(CPB), 10 minutes before the termination of CPB and 10 minutes after protamine administration. The ACT was measured with Hemochron 801 blood coagulation timer with 12 mg of either celite (C-ACT) or kaolin (K-ACT) used as surface activator. RESULTS: At 10 minutes after induction and heparin administration, celite and kaolin ACTs were l20+/-28, 541+/-247 seconds and 126+/-23, 559+/-267 seconds rcspectively. But 10 minutes after initiation of CPB and before the termination of CPB, celite ACTs were 941+/-238 and 787+/-277 seconds; kaolin ACTs were 605+/-182 and 499+65 seconds, which were consistently less than celite ACTs(p<0.01). At 10 minutes after protamine administration, celite ACT was 118+/-12 seconds and kaolin ACT was 142 56 seconds which was consistently more than celite ACT(p<0.05). CONCLUSIONS: We recommend the K-ACT rather than C-ACT when monitoring of heparin-induced anticoagulation in patients treated with high-dose aprotinin. It is also highly recommended that patients being added with aprotinin should receive the usual doses of heparin and that the ACT should be measured with kaolin as the activator.
Aprotinin* ; Blood Coagulation ; Cardiopulmonary Bypass ; Diatomaceous Earth* ; Heart-Lung Machine ; Heparin ; Humans ; Kaolin* ; Reoperation ; Thoracic Surgery* ; Transplants

BACKGROUND: High-dose aprotinin appears to enhance the anticoagulant effects of heparin, as documented by increases in the activated clotting times (ACTs) during cardiopulmonary bypass. This increase of the ACT in the presence of aprotinin and heparin is due to the use of celite as surface activator. We compared celite and kaolin as surface activators for the measurement of the ACT in cardiac surgical patients treated with high dose aprotinin. METHODS: This study included 25 patients who were scheduled for coronary bypass graft surgery and reoperation of cardiac valvular surgery. The 2 million units of aprotinin were added to the pump prime of heart-lung machine. The dosage of heparin and protamine was 3 mg/kg respectively. Whole blood was sampled 10 minutes after induction, heparin administration, cardiopulmonary bypass(CPB), 10 minutes before the termination of CPB and 10 minutes after protamine administration. The ACT was measured with Hemochron 801 blood coagulation timer with 12 mg of either celite (C-ACT) or kaolin (K-ACT) used as surface activator. RESULTS: At 10 minutes after induction and heparin administration, celite and kaolin ACTs were l20+/-28, 541+/-247 seconds and 126+/-23, 559+/-267 seconds rcspectively. But 10 minutes after initiation of CPB and before the termination of CPB, celite ACTs were 941+/-238 and 787+/-277 seconds; kaolin ACTs were 605+/-182 and 499+65 seconds, which were consistently less than celite ACTs(p<0.01). At 10 minutes after protamine administration, celite ACT was 118+/-12 seconds and kaolin ACT was 142 56 seconds which was consistently more than celite ACT(p<0.05). CONCLUSIONS: We recommend the K-ACT rather than C-ACT when monitoring of heparin-induced anticoagulation in patients treated with high-dose aprotinin. It is also highly recommended that patients being added with aprotinin should receive the usual doses of heparin and that the ACT should be measured with kaolin as the activator.
Aprotinin* ; Blood Coagulation ; Cardiopulmonary Bypass ; Diatomaceous Earth* ; Heart-Lung Machine ; Heparin ; Humans ; Kaolin* ; Reoperation ; Thoracic Surgery* ; Transplants