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Biomedical subjects

N Bleese

Publications and source records attributed to N Bleese.

At least 19 recordsLinked to original sources
PubMed1991

In situ localization of transforming growth factor beta 1 in porcine heart: enhanced expression after chronic coronary artery constriction.

We investigated the expression of transforming growth factor beta 1 (TGF-beta 1), a polypeptide differentiation factor probably associated with angiogenic properties in chronically hypoperfused heart tissue. A slowly swelling ameroid constrictor was implanted around the coronary circumflex artery (CX) of young domestic pigs. Two to three weeks after, significant CX stenosis of more than 90% and coronary collateralization could be demonstrated angiographically. The CX dependent experimental myocardial tissue (E) was investigated, with the LAD dependent area of the same pig serving as a control (C). We found significantly enhanced TGF-beta 1 mRNA expression by northern blot hybridization in the experimental myocardium (E) of those pigs with demonstrable coronary collaterals in the absence of a major myocardial infarction. The presence of TGF-beta 1 protein could be demonstrated quantitatively in extracts of the experimental and the control area by immunoblot analysis. By in situ techniques, TGF-beta 1 mRNA and protein could be localized predominantly in cardiac myocytes. We conclude that one adaptive mechanism of the pig heart in chronic coronary artery constriction is the enhanced expression of TGF-beta 1. Cardiac myocytes are a major source of TGF-beta 1. The observed coronary collateralization could be mediated-at least in part-by the angiogenic properties of TGF-beta 1.

Adaptation, Biological↗
PubMed1991

Impairment of the myocardial ultrastructure and changes of the cytoskeleton in dilated cardiomyopathy.

This study was designed to determine the morphological correlate of chronic heart failure. Myocardial tissue from eight patients undergoing transplantation surgery because of end-stage dilated cardiomyopathy was investigated by electron microscopy and immunocytochemistry using monoclonal antibodies against elements of the cytoskeleton: desmin, tubulin, vinculin, and vimentin. The tissue showed hypertrophy, atrophy of myocytes, and an increased amount of fibrosis. Ultrastructural changes consisted of enlargement and varying shape of nuclei, numerous very small mitochondria, proliferation of T tubules, and accumulation of lipid droplets and glycogen. The most obvious ultrastructural alteration was the decrease of myofilaments, ranging from rarefication to complete absence of sarcomeres in cells filled with unspecified cytoplasm. Immunocytochemistry showed that desmin was localized at the Z lines. In diseased myocardium, the amount of desmin was increased, but it was disorderly arranged. Tubulin formed a fine network throughout the myocytes and was significantly increased in cardiomyopathic hearts. Vinculin, a protein closely associated with the cytoskeleton, occurred not only at the sarcolemma and the intercalated disc but also within the myocardial cells. Ultrastructural changes and alterations of the cytoskeleton were severe in about one third of all cells. About one third of all cells showed moderately severe changes, and the remaining cells were normal. Vimentin was present in the interstitial cells and was increased in relation to the increase of fibrosis. We conclude that the increase of fibrosis, the degeneration of hypertrophied myocardial cells, and the alterations of the cytoskeleton are the morphological correlates of reduced myocardial function in chronic heart failure.

Antibodies, Monoclonal↗
PubMed1988

[Surgical aspects of the treatment and significance of angina pectoris].

Due to recent developments in modern interventional cardiology for the majority of patients with multi-vessel disease an indicatory and therapeutical grey-zone between bypass surgery and coronary angioplasty has arisen. Only patients with left main stenosis or uncomplicated one/two-vessel disease are generally accepted to be operated upon or treated by angioplasty, respectively. While pharmacological therapy is somewhat controlled by governments - surgical and cardiological interventional approaches are not. Even if it is justified to work out new interventional therapeutic approaches in the interest of its progress all of our current patients should in any case be informed concerning the risks of their treatment, prior to treatment.

Angina Pectoris↗
PubMed1987

[Heart surgery in acute bacterial endocarditis without preoperative heart catheterization. Long-term observation of 40 patients].

In 40 patients with acute bacterial endocarditis, the indication for cardiac valve replacement was established exclusively on the basis of the echocardiographic and clinical findings. The patients had an average age of 42 years and were under followup observation for an average of 2.2 years. The endocarditis involved the aortic valve 32 times, the mitral valve once, the tricuspid valve in two cases and the aortic and mitral valve together in five cases. In addition to the valve replacement, a ventricular septum defect and aneurysm of the ascending aorta had to be dealt with surgically in two cases each. The intraoperative and perioperative lethality was 2.5% (n = 1). The postoperative lethality was 12.5% (n = 5). In the surviving 34 patients, a recurrence of the endocarditis has not occurred up to now in any case. According to the NYHA classification, six of the surviving patients were to be classified as stage II and 28 as stage I, whereas stage III or IV had been present preoperatively in all cases. The postoperative echocardiographic investigation revealed a significant decrease of the left ventricular enddiastolic diameter (from 61 +/- 8 mm to 51 +/- 5 mm; P less than 0.001). In four cases, a slight insufficiency of the artificial valve could be detected. Reoperation was not necessary in any of these patients.

Adult↗
PubMed1986

[Pleural and mediastinal fibrosis with involvement of the external pericardium as a cause of decompensated heart failure].

Symptoms of cardiac failure were observed in a 60-year-old man 38 years after the therapy of cavernous tuberculosis of the right upper lobe with a paraffin oil plomb. The irritation by the paraffin oil induced a pleural and mediastinal fibrosis involving the pericardium. The rigid pericardium enclosed the heart and caused biventricular cardiac failure by the impaired diastolic filling. Possibilities of medical and surgical treatment are discussed.

Fibrosis↗
PubMed1979

Hemofiltration during extracorporeal circulation (ECC).

In cardiac surgery hemofiltration can be used: 1. to balance fluids during ECC, especially in long-term perfusion; 2. to carry out open heart procedures in patients with terminal renal insufficiency; 3. to treat acute hyperkalemia. The model of the 12.5 by 4.5 cm DIAFILTER TM and the model of operation are described. The compounds of the ultrafiltrate (UF) are identical with that of plasma water. Particles with a molecular weight of less than 50,000 can pass freely across the filtration membrane. The filtration capacity is 100 cc/min UF (Q blood: 300 cc/min, pressure across the membrane 600 mm Hg and hematokrit (Hkt) 25%). The technical details of operation are explained. Its general use as well as its simplicity is demonstrated in 10 patients.

Adult↗
PubMed1979

Clinical application of cardioplegia in aortic cross-clamping periods longer than 150 minutes.

Out of more than 1000 patients operated upon by means of cardioplegia in profound myocardial hypothermia (15 degrees - 20 degrees C) aortic crossclamping time exceeded 150 min in 26 cases. The average clamping time in this group of patients was 169 +/- 22 min (150 to 227 min). The average duration of the cardioplegic coronary perfusion was 35 +/- 21 min (14 to 99 min). The following procedures were performed. Aneurysmectomy of the ascending thoracic aorta combined with valve replacement (n = 7); valve replacement combined with aorto-coronary bypass procedures (n = 9); multiple valve replacement (n = 3); multiple coronary grafting (n = 6) and one complicated reoperation. Three patients (11.5%) died, none intraoperatively and none as the result of a heart failure connected with the operation.

Adenosine Triphosphate↗
PubMed1978

[Reversible myocardial ischaemia or irreversible myocardial fibrosis? Differentiation by biphasic 201thallium scintigraphy (author's transl)].

The results of biphasic 201thallium (201Tl) scanning were compared with those of coronary arteriography, left ventricular angiogarphy and stress ECG in 56 patients with coronary artery disease and six with no evidence of heart disease. There were 104 201Tl defects, 50 of them reversible. The defects were always located in the area supplied by a critically stenotic coronary artery. Correlation of regional wall motion with 201Tl activity demonstrated that in all forms of abnormal wall motion there was either ischaemia or fibrosis. The resting LV angiogram thus does not make it possible to distinguish between myocardial ischaemia and fibrosis. Taking the LV angiogram as a standard, the rate of false-positive 201Tl scintigrams was 5%, that of false-negative ones 23%. The biphasic 201Tl scintigram was more sensitive than the stress ECG in detecting myocardial ischaemia. It furthermore made it possible to localize the ischaemic (or fibrotic) region within the LV and to estimate its size.

Adult↗
PubMed1978

[Is creatine kinase isoenzyme CK-MB a diagnostic tool for perioperative myocardial infarctions? (author's transl)].

There is still controversy of the validity of elevated CK-MB serum activity in the diagnosis of perioperative myocardial infarction after open heart surgery. CK-MB activity was investigated using myocardial and skeletal muscle biopsies and in sera postoperatively in 192 patients. In biopsies CK-MB fraction of total myocardial CPK was 37%, the total-CPK activity of human skeletal muscles still shows a 5% fraction of CK-MB. There has to be more than 8% CK-MB fraction of total CPK-serum-activity to take this as evidence of myocardial damage. 3 h postoperatively enzymatic-immunologic CK-MB test is no longer interfered by enzymes derived from hemolyzed erythrocytes. In patients without signs of myocardial lesions postoperatively mean CK-MB-activity is 11 to 27 U/1 depending on the operative procedure performed. Activity levels exceeding 50 U/1 are almost evident of myocardial infarction. Elevated CK-MB-serum activity is a sensitive parameter for myocardial lesions overestimating an event of infarction. It is a helpful tool diagnosing perioperative myocardial infarction.

Cardiac Surgical Procedures↗
PubMed1977

[Prevention of edema during coronary perfusion with cardioplegic solution (author's transl)].

In arrested and with cardioplegic solutions perfused rabbit hearts the relation of perfusion-pressure and flow rate were examined, showing that edema of the myocardium can be avoided even using erythrocytes-free solutions by two measures. First the solution has to contain colloid active agents and secondly the perfusion pressure has to be significantly below the colloid-osmotic pressure. Furthermore the edema can be avoided by adding 300 mg 6-methyl prednisolone/1. If no attention is paid to these facts the coronary flow decreases constantly due to developing interstitial and interfibrillar edema and degenerative changes of endothelial cells of the capillaries, which even can undergo necrosis. These changes were not seen using steroids. On the contrary here we found by densitometry and increased number of lysosomes. These findings show the effectiveness of corticosteroids in stabilizing the cell membranes.

Animals↗
PubMed1976

[Long-term cardiac arrest by cardioplegic coronary perfusion (author's transl)].

UNLABELLED: The Mg++ aspartate-procaine-cardioplegia has been proven in animal experiments as well as from 1970 til 1975 in more than 1000 open-heart-procedures by a myocardial temperature of 32 degrees C and aortic crossclamping time up to 40 minutes superior to all other known procedures of cardiac preservations. To guarantee a safe myocardial protection of the arrested heart for a remarkable longer period of total ischemia, we further developed the cardioplegic technique in the animal lab, and use it now clinically. PRINCIPLE: The arrest is induced by cardioplegia (Mg++ aspartate-procaine), than the arrested heart is cooled down to 15-20 degrees C by cardioplegic coronary perfusion maintaining the oxidative metabolism. The perfusion is stopped. The begin of ischemia is still under normal ATP-levels and continuous cardioplegia. TECHNIQUE: 1. Crossclamping of the aorta; 2. cardioplegic induced cardiac arrest by Mg++ aspartate-procaine (Kirsch); 3. Surface cooling of the heart; 4. Coronary perfusion by hypothermic cardioplegic solution (8-10 min, flow 80-120 ml/min, perfusion pressure maximal 30 mmHg). Perfusate: O2-saturated, erythrocyte free, 6% hydroxyethyl starch solution added 2 mM Mg++ aspartate, 4 mM procaine, 50 mM Na+, 5 mM K+, 0,5 mM Ca++, 25 mM HCO3-, 10 mM glucose, 200 mM mannitol, 250 mg/l 6-methylprednisolone. RESULTS: 84 patients (29 ACVB; 55 valve replacements); crossclamping time: 71 min (SD 22); total time of ischemia: 57 min (SD 18; max 96, min. 27 min); reperfusion time restoring normal excitation-contraction of the heart: 3 min (SD 2); weaning off bypass: 23 min (SD 14). Hemodynamic 12 h postop.: SO2 venous 76% (SD 6). No sympathicomimetics were used. Only 30% of myocardial ATP is splitted after 120 min of cardiac arrest. Electron microscopic findings show only small, reversible alterations of fine structure.

Adenosine Triphosphate↗
PubMed1975

[Metabolism and ultrastructure of magnesium aspartate-procaine arrested hearts of rabbit and man (author's transl)].

In normothermia, mild, and deep hypothermia the metabolism and the electron microscopic structure were investigated in human and rabbit heart muscle after magnesium aspartate-procaine cardioplegia. In comparison to plain ischaemic arrest splitting of adenine nucleotides and glycogen was significantly reduced in all experiments with the induced cardioplegic arrest. For 40 min at 32 degrees C almost no changes in ultrastructure were seen in heart muscle after induced arrest, while severe and/or irreversible damages were seen in the cell structure of the heart muscle due to plain ischaemic arrest.

Adenine Nucleotides↗
PubMed1975

[Diagnosis, frequency and importance of the "low-output-syndrome" in the postoperative period after mitral valve replacement (author's transl)].

From 1970 until 1975 single mitral valve replacement was carried out in 162 patients using Björk-Shiley disc prostheses. The surgical mortality (within 30 days postoperatively) was 9.3% (n=15). Out of these 15 patients 9 died due to myogenic cardiac insufficiency. 21 patients with "Low-output-Syndrome" due to myogenic insufficiency however survived. The improvement of intraoperative myocardial protection since 1972 (using hypothermia and cardioplegic induced cardiac arrest) reduced the frequency of myogenic cardiac insufficiency to 1%. Unrelated to the above mentioned we saw in 18.5% of all patients after ECC-procedures a temporary "Low-output-Syndrome" after the 3rd postoperative day due to pericardial effusion.

Cardiac Output↗
PubMed1975

[Artificial respiration as treatment of postoperative complications after cardiovascular surgery: indication, technique, results (author's transl)].

From 1972 to 1974 524 patients underwent surgery with extra corporal circulation. 83 (15,8%) patients had to be postoperatively ventilated for a prolonged period or reintubed after a symptomfree interval due to anticipated or manifested complications. 31 (37%) out of these expired. There was no death due to the prolonged ventilation itself, shown by the group, in which the causes for the above treatment were others but respiratory failure or insufficiency. All patients of this group survived. Indications, technique and results are described and discussed.

Germany, West↗
PubMed1975

[Treatment of postoperative renal insufficiency after cardiovascular surgical procedures by peritoneal dialysis (author's transl)].

In 1972 and 1973 there have been 698 (351 with ECC) cardiovascular surgical procedures. 29 cases of renal insufficiency were seen in this group, 15 requiring peritoneal dialysis. There were only two survivors in the latter group. However none died due to renal insufficiency. The indication, technique, complications, results are discussed in detail.

Acute Kidney Injury↗
PubMed1975

[Surgical treatment of coronary heart disease (author's transl)].

Until 1974 146 patients underwent coronary surgery in Hamburg. The total mortality rate for the first 100 postoperative days was 16,3 per cent. In the last years the mortality was reduced to 14 per cent. This group included all different selective and emergency surgical procedures for coronary disease. Due to the different degree of the coronary disease and/or of the impairment of the left ventricular function the mortality ranged between 0 per cent and 35 per cent. Some clinical parameters influencing the mortality rate are discussed.

Adult↗