Biomedical subjects

Oliver Kempski

Publications and source records attributed to Oliver Kempski.

23 records · Page 2Linked to original sources

PubMed2002

Early albumin infusion improves global and local hemodynamics and reduces inflammatory response in hemorrhagic shock.

OBJECTIVE: To evaluate the effects of an early, short-term albumin infusion on mesenteric microcirculation and global hemodynamics in hemorrhagic shock. DESIGN: A prospective, randomized study. SETTING: Animal laboratory at a university medical clinic. SUBJECTS: Seventeen Sprague-Dawley rats weighing 250-400 g. INTERVENTIONS: The rats underwent median laparotomy and exteriorization of an ileal loop for intravital microscopy of the mesenteric microcirculation. Volume-controlled hemorrhagic shock was provoked by arterial blood withdrawal (2.5 mL/100 g body weight for 60 mins), followed by a 4-hr reperfusion period. Albumin (20%) or 0.9% NaCl was administered intravenously as a continuous infusion for 30 mins at the beginning of reperfusion. Reperfusion time mimicked a "prehospital" phase of 30 mins followed by a quasi "in-hospital" phase of 3.5 hrs. The "in-hospital" phase in both groups was initiated by substitution of blood followed by reperfusion with normal saline. MEASUREMENTS AND MAIN RESULTS: Central hemodynamics, mesenteric microcirculation, and arterial blood gas parameters were monitored before, during, and 60 mins after hemorrhagic shock, and for a 240-min follow-up period after initiation of reperfusion. Application of albumin markedly reduced rolling and adherent leukocytes, maximum velocity, and shear rate in the mesenteric microcirculation. Later, after improvement of mesenteric microcirculation, an intermittent increase of central venous pressure and abdominal blood flow and decrease of hematocrit was observed. CONCLUSIONS: Albumin treatment of hemorrhagic shock improves microcirculation and global hemodynamics and attenuates the inflammatory response to reperfusion. It may provide clinical benefit when applied at an early stage of reperfusion during hemorrhagic shock.

Albumins↗

PubMed2002

Histological findings in coil-packed experimental aneurysms 3 months after embolization.

OBJECTIVE: Knowledge regarding tissue reactions within coil-packed aneurysms is poor. The purpose of this study was to analyze histological changes in a chronic experimental bifurcation aneurysm model that might explain the protective effect of Guglielmi detachable coils. METHODS: The aneurysms were produced by means of a venous graft pouch at a surgically created bifurcation of the carotid artery in the neck of rabbits. After 3 weeks, embolization with Guglielmi detachable coils was performed in the treatment group but not in the control group (seven rabbits each). At the time of embolization, six of seven treated aneurysms were completely occluded according to radiological criteria. Twelve weeks later, all aneurysms were explanted after final angiography. Histological examinations were performed with coils in situ. RESULTS: Six of seven embolized aneurysms demonstrated complete occlusion in final angiography. But gross pathology revealed that all specimens had differently sized open cavities between the coils. In only two cases, these spaces were very small and the aneurysmal sacs were filled with coils and tissue by more than 90%. Light microscopy demonstrated intraluminal granulation tissue and strong chronic inflammatory wall thickening with numerous foreign body cells at the interface between coils and tissue. Coils were partially incorporated into the aneurysmal wall, sometimes close to the surface and occasionally even outside the wall within the surrounding tissue. CONCLUSION: The protective effect of Guglielmi detachable coil treatment in our chronic experimental bifurcation aneurysms results from formation of intraluminal granulation tissue and wall thickening attributable to chronic inflammation.

Animals↗

PubMed2002

Low-frequency ultrasound induces nonenzymatic thrombolysis in vitro.

OBJECTIVE: To evaluate whether ultrasound, applied over a distance of several centimeters and in the absence of thrombolytic agents, may have a thrombolytic effect on blood clots. METHODS: Low-frequency (20 kHz) continuous wave ultrasound at different intensity levels (0.15-1.2 W/cm2) and exposure times (5, 10, and 20 minutes) was assessed for its potential to induce thrombolysis of fresh human blood clots. The ultrasound effect was also studied in combination with recombinant tissue-type plasminogen activator-mediated thrombolysis. Experiments were carried out in a flow model in degassed sodium phosphate buffer at 37 degrees C at a distance of 3 cm from the ultrasonic probe to the blood clots. Regardless of ultrasound exposure times, blood clots in all experimental groups and the control group were left in the flow system for 20 minutes. RESULTS: The use of ultrasound alone showed a significant thrombolytic effect compared with the control group, with a statistically significant effect at 0.15 W/cm2 and exposure of 10 minutes (P = .02). There was a clear correlation between the extent of weight loss and the chosen intensity level and exposure time. Complete disruption in 8 of 10 blood clots occurred at 1.2 W/cm2 within 10 min. Addition of ultrasound to recombinant tissue-type plasminogen activator-mediated thrombolysis significantly enhanced thrombolysis compared with application of recombinant tissue-type plasminogen activator or ultrasound alone (P = .0001), with the results pointing toward a purely additive, nonsynergistic effect of the 2 treatment modalities. Lysis was more effective in fresh thrombi. CONCLUSIONS: The use of low-frequency ultrasound alone, without addition of a thrombolytic drug, has the potential to induce thrombolysis over a distance. Combination of ultrasound with recombinant tissue-type plasminogen activator is superior to either treatment alone. Ultrasound is a promising tool for developing an alternative or additional treatment modality for acute cerebral vessel occlusion.

Humans↗

PubMedDate not supplied

Shunting of the microcirculation after mesenteric ischemia and reperfusion is a function of ischemia time and increases mortality.

OBJECTIVE: Shunting of the microcirculation contributes to the pathology of sepsis and septic shock. The authors address the hypothesis that shunting of the microcirculation occurs after superior mesenteric artery occlusion (SMAO) and reperfusion, and explore functional consequences. METHODS: Spontaneously breathing animals (rats) (n = 30) underwent SMAO for 0 (controls), 30 (SMAO_30) or 60 min (SMAO_60) followed by reperfusion (4 h) with normal saline. Leukocyte-endothelial interactions in mesenteric venules were quantified in an exteriorized ileal loop using intravital microscopy. Abdominal blood flow was recorded continuously, and arterial blood gases were analyzed at intervals. The above groups were matched by comparable groups with continuous superior mesenteric artery blood flow measurements and without exteriorizing an ileal loop (controls*, SMAO_30*, SMAO_60*). RESULTS: Adherent leukocytes increased shortly after reperfusion in ischemia groups, and plateaued in these groups. Centerline velocity in the recorded venules was significantly reduced after reperfusion down to low-flow/no-flow in SMAO_60 as compared to SMAO_30 and controls, whereas perfusion of the SMA and ileal vessels persisted. The microcirculatory changes in SMAO_60 were accompanied by progressive metabolic acidosis, substantially larger volumes of intravenous fluids needed to support arterial blood pressure and significantly reduced survival (30%). SMA blood flow increased in relation to abdominal blood flow after reperfusion in SMAO_60*, and remained constant in SMAO_30* and controls*. Survival was 80% in SMAO_60*. CONCLUSION: Shunting of the microcirculation can be observed after SMAO for 60 min and reperfusion, and contributes significantly to the pathology of mesenteric ischemia and poor outcome.

Animals↗

PubMedDate not supplied

Action and efficacy of p-[131I]iodo-L-phenylalanine on primary human glioma cell cultures and rats with C6-gliomas.

BACKGROUND: Recently we demonstrated high selectivity and long retention of p-[123I]iodo-L-phenylalanine (IPA-123) for diagnostic purposes in gliomas. Here we describe the potency of the iodine-131-labelled analogue p-[131I]iodo-L-phenylalanine (IPA-131) for experimental treatment of gliomas. MATERIALS AND METHODS: Two human glioma cell cultures and 15/20 rats with C6-gliomas were exposed to IPA-131. RESULTS: After 24-h-exposure the cell number of the glioma cell cultures was reduced by 77% and 79%, respectively. Four out of five untreated rats died 8-24 days after implantation and had verifiable tumours. Seven animals died despite therapy, while 8 were soon healthier, gained body weight and were sacrificed 81 days after implantation, at which time survival of the treated animals was significantly prolonged (p < 0.05). At autopsy, instead of tumours there were substance defects, surrounded by pre-existing parenchyma infiltrated by probable tumour cells that were not discernible from reactive astrocytes, lymphocytes, monocytes and multinuclear giant cells. CONCLUSION: IPA-131 has promising activity against human glioma cells in vitro and experimental gliomas in vivo.

Animals↗