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Biomedical subjects

B Braun

Publications and source records attributed to B Braun.

At least 199 records · Page 11Linked to original sources
PubMed1975

[Spironolactone and thiabutazide in the treatment of essential hypertension (author's transl)].

The anti-hypertensive effect of spironolactone and thiabutazide was tested on 47 unselected patients with primary hypertension. They were divided into two groups according to the change in plasma-renin activity in response to furosemide administration: those with and those without response to stimulation, and sub-groups with low, normal or high plasma-renin activity (low renin hypertension; normal renin hypertension; high renin hypertension). During both 4-week treatment periods there was a distinct fall in systolic blood pressure, most marked in the patients without plasma renin stimulation (after spironolactone of about 26.2 mm Hg, after thiabutazide 29 mm Hg), the diastolic pressure fall being only slight in all groups (about 5-10 mm Hg). The plasma-renin activity and plasma-aldosterone concentration increased in all groups, after both spironolactone and thiabutazide three-to fourfold compared with the basal value, even in patients without change in plasma-renin activity after furosemide injections. Serum sodium content decreased after administration of spironolactone, increasing again after subsequent thiabutazide administration. Serum potassium content increased after spironolactone, decreasing after thiabutazide. There was no significant difference between either individual groups or different treatment periods with spironolactone or thiabutazide as far as weight, urine volume or electrolyte excretion in 24-hour urine was concerned.

Aldosterone↗
PubMedDate not supplied

[Mitral valve and mitral ring movement in mitral stenosis. An ultrasonic study with different valve models (author's transl)].

We constructed three different mitral valve models in order to investigate the different mechanisms which account for the concordant opening and closing movement of the posterior compared to the anterior mitral valve in mitral stenosis. Three different types of movements are possible: a dorso-anterior movement of the mitral ring, opening and closure of the valve itself and a rotation of the entire valve apparatus. Our in-vitro studies showed that the best explanation for the concordant diastolic movement of the posterior valve is given by the assumption that during the early diastolic opening phase of the valves the whole stenotic valve apparatus is rotated upward, i.e. towards the transducer. This rotation, has a higher amplitude compared to the residual downward-oriented opening movement of the posterior valve.

Mitral Valve↗
PubMedDate not supplied

Transesophageal echocardiographic artifact mimicking pseudoaneurysm of the aorta.

Transesophageal echocardiography (TEE) is a sensitive and specific procedure that gives detailed images of the thoracic aortic anatomy and blood flow; however, there are few reports on pitfalls with TEE. This case describes a patient with a typical history of a possible aortic rupture; artifacts in the TEE mimicked aortic rupture and development of a pseudoaneurysm. Echocardiographers should know this possible pitfall to make the correct diagnosis.

Aneurysm, False↗
PubMedDate not supplied

A modified method for experimental candidosis in mice avoiding lethality.

A model is presented which selected one out of 150 Candida albicans strains for the evaluation of antifungal agents. The mice were inoculated with 6 x 10(5) CFU of strain 352 into the tail vein. The strain has a moderate phospholipase B (PLB) activity in vitro and was originally isolated from a stool sample from a patient in an intensive care unit. This infection leads to very little suffering in the infected animals during the 6-day observation period. Kidney counts at day 5 after infection can give a first indication for a possible fungistatic mechanism. Possible interesting drugs can then be evaluated by a second set of experiments using a longer observation time to investigate the compounds for fungicidal properties. The model suggests that screening for systemic antifungals by avoiding lethality of mice in the first place can be done.

Animals↗
PubMedDate not supplied

Development and long-term fate of a cellular lining in fibrous polyurethane vascular prostheses implanted in the dog carotid and femoral artery. A scanning and light microscopical study up to 53 months after implantation.

The development and long-term fate of the inner cellular lining in 72 small caliber (3 mm inner diameter) fibrous polyurethane vascular prostheses explanted from dog carotid and/or femoral arteries at times ranging from 1.5 weeks up to 53 months after implantation were studied by scanning electron and light microscopy. A continuous cellular ingrowth from the vascular stumps into the 3 cm long prostheses was observed, which eventually resulted in a complete cellular lining 6 months after implantation. No other ways of endothelialization were noted. In fully endothelialized prostheses, the cellular ingrowth extended approximately 8 mm into the prostheses and consisted of several layers of fibroblasts and smooth muscle cells, covered by a very thin endothelioid cell layer. The newly developed lining was firmly anchored onto the inner prosthetic surface by means of cellular protrusions extended into the fibrous texture of the prosthetic wall. It was concluded that under experimental conditions in the dog complete endothelialization can be obtained in fibrous polyurethane vascular prostheses and that the lining remained thin and stable throughout the observation period of 53 months after implantation.

Anastomosis, Surgical↗
PubMedDate not supplied

Thrombus formation in deep venous thrombosis. A clinical approach to diagnosis and control of lysis efficacy.

The efficacy of fibrinolysis in deep venous thrombosis (DVT) depends on the age and organization of the thrombus as well as its localization. Up to now, indication for lysis therapy is defined according to the duration of clinical symptoms (less than 7 days). Our lysis results in urokinase therapy (n = 87) with high-dose and long-term regimen (mean 7.8 days), however, have shown no correlation between the duration of clinical symptoms (up to six weeks) and lysis efficacy (p less than 0.05). Therefore phlebographic criteria were established to allow the differentiation of fibrinolytic therapy depending on the site of the thrombus, its localization and the formation of collateral veins. In order to determine the state of thrombus organization, we used a new ultrasound Duplex system device (ARTIS, 7.5 Mhz, Picker International). In vivo experiments with induced thrombosis in human vena saphena magna demonstrate that echodensity of thrombi in ultrasound starts at the 11th-15th day. These findings are in good agreement with pathological studies of thrombus formation. Recent results of 24 patients with DVT indicate that echodensity of thrombus in ultrasound correlates with the course of organization and the efficacy of later lysis therapy.

Adult↗
PubMedDate not supplied

Endothelialization of polyurethane vascular prostheses implanted in the dog carotid and femoral artery.

A new type of vascular prosthesis made of polyurethane with a fibrous structure of the wall was implanted in the carotid and/or femoral artery of dogs. The healing process and neo-intima formation after implantation of this type of prosthesis was followed with light- and scanning electron microscopy. A total of 18 prostheses, which had been implanted for 1, 3, 6, 9 or 20 weeks were studied. Endothelial like cells invaded the prosthesis over the anastomoses, starting the first week after implantation. The growth zones advanced steadily, and prostheses measuring 3 cm in length were completely endothelialized by 20 weeks after implantation, a mean growth rate of the endothelial like cells of 0.09 mm/day. Subsequently, fibroblasts and smooth muscle cells grew between the neoendothelial layer and the prosthetic inner surface, forming a new multi-layered neo-intima. Cellular elements of the neo-intima were firmly anchored onto the inner wall of the prosthesis by cells with extending cytoplasmic protrusions between the fibers of the prosthetic wall. Since in this type of fibrous polyurethane prosthesis, endothelial like cells continually grew until a new lining was formed, apparently facilitated by the fibrous structure of the wall, further investigations are indicated for progression toward clinical implantation of this type of prosthesis.

Animals↗
PubMedDate not supplied

A fibrous polyurethane microvascular prosthesis. Morphological evaluation of the neo-intima.

A fibrous polyurethane microvascular prosthesis with an inner diameter of 1.5 mm was implanted to replace the rat aorta between the left renal artery and the bifurcation of the aorta. Twenty-four implantations, using three different lengths (0.5; 1; 1.5 cm), were carried out. Rats were sacrificed 3, 6, 9 and 12 weeks after implantation. Only 1 prosthesis was occluded (probably due to a technical error). Grafts were already lined with a neo-intima by the third week, irrespective of their length. Different shapes of endothelial cells were recognized. It appeared that cells arise and migrate from the aortic stumps into the prosthesis, since the neo-intima is thicker in the anastomotic area than in the middle of the graft. The well-defined neo-intima consisted of several layers of smooth muscle cells embedded in a glycoprotein matrix and covered by a very flat continuous endothelium. The structure of the prosthesis allowed anchoring of the lining cells. Migration of cells through the wall of the prosthesis was not observed. At those places in the prosthesis where fibres had fused together to form flat areas the neo-intima became torn by the contraction of the myofibroblasts. This was because the cells had evidently failed to become anchored to the prosthetic wall. The neo-intima retained the ability of immediate repair of small defects which develop occasionally on the non-fibrous areas of the luminal surface of the prosthesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

The endothelialization process of a fibrous polyurethane microvascular prosthesis after implantation in the abdominal aorta of the rat. A scanning electron microscopic study.

The endothelialization process of a fibrous microvascular polyurethane prosthesis (inner diameter 1.6 mm) was studied by scanning electron microscopy. Forty-seven prostheses (1 cm) were implanted into the abdominal aorta of rats between the left renal artery and the bifurcation. Specimens were taken on day 1, 3, 5, 7, 10, 14, 18, 21 and 25, as well as 6 and 9 months after implantation, to evaluate immediate and delayed response and complications. The patency rate of the implants was 91.2%. After an initial recovery period of five days, endothelial cells started to migrate onto the inner surface of the prosthesis with a velocity of approximately 0.3 mm per day, resulting in a completely endothelialized prosthesis at day 21. A smooth continuous inner lining was achieved. A difference in growth pattern between the proximal and distal growth zone was observed, and may be attributed to the direction of the blood flow through the prosthesis. The endothelial cells advanced in a close arrangement. No cells were seen to settle and grow in between the two growth zones on the fibrin layer. If no immediate complications occur, the endothelialization process (21 days) proceeds uneventfully and no late complications are observed. Though it may be argued that the new cells lack some authentic endothelial features, this study indicates that they are at least of endothelial orgin, and behave morphologically like endothelial cells. It can be concluded that the adequate texture of the prosthesis and the cell anchoring, in combination with both an optimal surgical performance and blood flow, ensure that the microvascular prostheses are rapidly endothelialized and retain high patency rates over long periods of time.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗