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Biomedical subjects

K Bürger

Publications and source records attributed to K Bürger.

At least 37 records · Page 2Linked to original sources
PubMed1995

Perioperative vascular flushing perfusion in acute mesenteric artery occlusion.

AIM: To evaluate in animals and patients a perioperative vascular flushing perfusion with antioxidants in order to improve postischaemic condition of the bowel and hence, to prolong the warm ischaemia tolerance time. MATERIALS: 40 rats and 10 patients with acute mesenteric artery occlusion. METHODS: Intestinal ischaemia was induced in 40 rats by clipping the superior mesenteric artery for 1 h. Thirty animals received a vascular flushing perfusion with oxygen radical scavengers (ascorbate, tocopherol or oxypurinol). Histology, ATP, ADP levels were examined in tissue biopsies and malondialdehyde, lactate dehydrogenase, alkaline phosphatase levels were measured in blood during ischaemia and 60 min after reperfusion. RESULTS: ATP restoration was particularly improved in the oxypurinol group (ATP/ADP-ratio = 2 vs. 1.2 in the control group). Malondialdehyde increase observed after reperfusion as a marker of radical induced lipid destruction was significantly attenuated (control group 160% of base level vs. 127% in the ascorbate group, 133% in the tocopherol group, 121% in the oxypurinol group). Histological alterations during ischaemia/reperfusion were markedly less extensive in the perfusion groups than in control. The patients treated perioperatively with arterial flushing perfusion had an overall mortality of 10%. CONCLUSION: Vascular flushing perfusion with oxygen radical scavengers prevents radical induced ischaemic damage and may prolong the warm ischaemic tolerance time of the intestine.

Acute Disease↗
PubMed1995

[Evaluating the extracranial cerebral arteries with ultrasound angiography].

AIM: Ultrasound angiography is a new method of colour-coded vessel imaging. The present study aimed at giving further information on its clinical utility in neurosonology. METHOD: The extracranial arteries of 53 patients and 5 normal persons were investigated by ultrasound angiography in comparison with colour-coded duplex sonography. RESULTS: We found a sharper imaging of stenoses and plaques by ultrasound angiography compared with colour Doppler. The imaging of the vessels can be achieved more continuously, avoiding dropouts of the colour. Small vessels and branches can be detected more reality. CONCLUSION: Ultrasound angiography represents a valuable additional imaging technique to colour-coded duplex sonography, providing further information, especially with regard to the border of plaques and stenoses.

Blood Flow Velocity↗
PubMed1995

[The value of color-coded duplex ultrasound in the immediate postoperative phase of carotid artery reconstruction].

Diagnostic value of color-coded duplex sonography within the first hours following carotid artery reconstruction was investigated. We examined 15 out of 290 patients who developed neurologic symptoms after carotid endarterectomy. During the early postoperative period color-coded duplex sonography was associated with some problems. The investigation at this time was characterized by poor quality of B mode and color Doppler. It may be caused by deposition of air or bleeding. Differentiation of internal and external carotid arteries was difficult. When Doppler sonography of the reconstructed carotid artery was additionally performed, more accurate information was obtained. A normal reconstructed internal carotid artery was found in 8 patients, whereas 5 patients showed pathologic results (3 stenoses, 1 total occlusion, 1 embolisation). In patients with pathologic changes reoperation was immediately performed. Results of ultrasound investigations were proved by intraoperative findings. In 2 patients examination of the reconstructed internal carotid artery was impossible even by the combination of duplex and Doppler sonography. We conclude that color-coded duplex sonography in combination with Doppler sonography is a valuable method for investigations in the early postoperative period following carotid artery reconstruction.

Adult↗
PubMed1995

[Reconstruction of brain-supplying arteries with bilateral monitoring by transcranial Doppler ultrasound--new aspects for technical surgical procedures].

From January to June 1994 reconstruction of 61 internal carotid arteries (ICA) with cerebral monitoring using bilateral transcranial Doppler sonography in the Clinic of Vascular Surgery Charité was performed. Recording of the maximal mean blood flow velocity in both middle cerebral arteries (MCA) was performed intraoperatively. After clamping of ICA flow velocity in the ipsilateral MCA decreased immediately but recovered within short time in 60% of our patients (Vmean > 25 cm/s). Based on the reaction of the contralateral MCA 3 types were differentiated: 1) Vmean of the contralateral side changed contrary to the ipsilateral side (compensation, "scissors type"). 2) The contralateral side did not react ("indifferent type"). 3) The contralateral side changed parallel to the ipsilateral side ("parallel type"). In 62% of our patients the operative strategy was influenced by transcranial Doppler monitoring: in 35% of cases the operative reconstruction was performed without intraluminal shunting, in 19% of cases the position of the intraluminal shunt was corrected, in 8% of cases the blood pressure was increased. Doppler signals due to emboli were registered in 43% of our patients. These patients did not show any new neurologic signs and symptoms. In one patient who developed a neurological deficit during the postoperative phase, emboli signals were recorded during a period of 30 minutes. Bilateral transcranial Doppler monitoring, especially in patients with contralateral high-grade stenoses or occlusions of the ICA, is a useful method for intraoperative cerebral monitoring. We recommend its application on a wide scale.

Blood Flow Velocity↗
PubMed1995

[Indications and clinical experiences with the use of central shunts for chronic hemodialysis].

Central av-shunts are indicated in patients who underwent multiple operations for dialysis access on the extremities or became periphero-vascular inoperable due to local infections. Between 1982 and 9/1994 116 patients had been operated. 71 patients obtained a subclavio-subclavial shunt, 13 patients a subclavio-jugular shunt and 32 patients a femoro-femoral shunt. As acute postoperative complication we found in seven patients an early thrombosis 2 to 6 days after operation, which could be thrombectomized unproblematically. Two patients after subclavio-subclavial shunt operation and 3 patients after femoro-femoral shunt acquired an infection of the prosthesis, which made the removal of the prosthesis necessary. In one patient with carcinoma a ligation of the av-shunt was done because of an extreme venous congestion due to a benign stenosis of the iliacal vein. Late thromboses were found in 15 patients. These occlusions were thrombectomized after anticoagulation or in case of complete occlusion of the collecting vein were treated by an extension of the prosthesis to another central vein. 35 patients died 15 days to 9 years (mean 6.4 years) after operation. It can be concluded that central av-shunts show a stable long-term function.

Adult↗
PubMed1994

Substance P-like immunoreactivity in the hypothalamic suprachiasmatic nucleus of Phodopus sungorus--relation to daytime, photoperiod, sex and age.

The immunohistochemical distribution of substance P (SP) in the hypothalamic suprachiasmatic nucleus (SCN) was studied in adult male and female Djungarian hamsters (Phodopus sungorus) held under either long or short photoperiods. Intact animals were killed by perfusion with a fixative at the middle of the light or dark periods, respectively. The tissue was processed by routine immunohistochemical methods. Perikarya exhibiting SP-like immunoreactivity (LI) were found in the SCN of animals of all groups. These cell bodies predominantly were restricted to a distinct portion of the nucleus extending less than 150 microns rostrocaudally and were often concentrated in its lateral aspect. SP-LI fibers were rarely observed in the SCN, however, other hypothalamic parts, e.g. anterior and paraventricular regions, exhibit strong SP-LI innervation patterns. Sex-related differences were not observed. Long-term exposure to short days decreased the number of neurons exhibiting SP-LI by approximately 60% when compared to long-day animals at both day- and nighttime. At night, SP-LI neurons were augmented in number by 34% (long-day group) and 56% (short-day group). Further, the numbers of SP-LI perikarya in the SCN of aged hamsters at day- and nighttime were augmented 3- to 4-fold when compared to adult animals. These results suggest that substance P in the SCN is involved in the regulation of circadian and seasonal mechanisms in this highly photoperiodic rodent species.

Aging↗
PubMed1994

[Initial experiences with ultrasound angiography in the area of extracranial and peripheral arteries].

First experience with ultrasound angiography of extracranial and peripheral arteries in 20 patients is reported. Ultrasound angiography is a new method of color-coded vessel imaging. It is based on signal processing of the blood flow amplitudes. Color imaging of echo signals by ultrasound angiography is independent of the direction and velocity of blood flow and of the angle of ultrasound beam. Aliasing and changes of colors due to changes of direction do not exist. We found a sharper imaging of the vessel lumen and the vessel wall compared with color Doppler. Imaging of vessel branches and small vessels is even better. Documentation of vessels by ultrasound angiography is similar to angiography and can be obtained convincingly. Application of this method in addition to color-coded duplex sonography is recommended.

Adult↗
PubMed1993

[The disease picture of atypical aortic coarctation].

The atypical coarctation of aorta is a very rare disease. Approximately 1-2% of all coarctations are not localized in isthmus aortae. The etiology of this disease is still unknown. There are existing opinions about acquired and also congenital origin.

Adult↗
PubMed1989

[Surgical treatment of renovascular hypertension in children].

The main reason for renovascular hypertension in children is ideopathic fibrous and fibromuscular displasia. The pathogenetic classification of the disease was worked out in 1971 by Harrison and McCormac. Of all cases of hypertension in children between 5 and 20% are of renovascular origin. The illness demands an absolute necessity for treatment. The concept of management of renovascular hypertension includes the conservative treatment as well as angioplasty and especially the surgical reconstruction of the arteries. Nephrectomy should be considered as the treatment of last resort. For the surgical reconstruction of arteries a variety of techniques are available. Aortorenal bypasses using autologous arterial or venous grafts are expecially suitable in surgical treatment of renovascular hypertension in children. Results given in literature of the management of 334 children with renovascular hypertension and 8 own cases were evaluated by us according to the criteria of the National Heart, Lung and Blood Institute. In the majority of surgical treated children a substantial improvement in the state of health, or cure, could be achieved.

Adolescent↗
PubMed1989

[Surgical treatment of extracranial occlusive processes of the vertebral artery by construction of a subclavio-vertebral bypass].

An account is given of causes and clinical patterns of vertebro-basilar insufficiency, before reference is made to patients treated at the Surgical Department of Charité to describe indications for surgery, diagnostic approach, and various surgical techniques. A particular role is played, in this context, by stenoses and occlusions of the vertebral artery in the bone canal of the cervicovertebral column. Subclavio-vertebral bypass is a new surgical technique recommended for surgical treatment of that kind of vascular processes.

Adult↗
PubMed1988

[Chronic circulatory disorders of the digestive organs of the abdominal cavity. Causes, clinical aspects and treatment].

Chronic arterial insufficiency of blood supply to digestive organs in the abdominal region is a specific manifestation of circulatory diseases. It is rare but may cause substantial danger to the patient. Reference is made in this paper to international literature as well as to cases involved in vascular surgery at the Berlin School of Medicine (Charité) for an account of present knowledge on aetiology, pathogenesis, symptoms, diagnosis, and therapy of chronic disorders of abdominal blood supply. Techniques of vascular repair represent an appropriate therapeutic concept, accurate diagnosis and critical indication provided.

Arterial Occlusive Diseases↗