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Biomedical subjects

E Merikallio

Publications and source records attributed to E Merikallio.

At least 37 records · Page 2Linked to original sources

Myocardial catecholamines and their biosynthetic enzymes in various human heart diseases.

Myocardial noradrenaline (NA) content, together with the activities of the enzymes tyrosine hydroxylase (TH) and dopamine beta-hydroxylase (DBH) was measured in biopsy specimens taken during cardiac surgery from patients with various heart diseases. Fluorescence histochemical studies were also performed on comparable specimens. The mean NA content in patients with symptomatic ischaemic heart disease (IHD) was significantly higher than that in patients with valvular heart disease (VHD), atrial septal defect (ASD) or congestive heart failure (CHF). The lowest mean NA content was found in patients with CHF. The activities of TH and DBH were highest in the IHD group, although the differences between IHD and VHD groups were not significant. Histochemical investigations of adrenergic structures showed less fluorescence intensity in the CHF than in the other 3 groups. On the other hand, the density of the adrenergic nerve net and the size and number of varicosities were greatest in patients suffering from IHD. The significance of these results is discussed in relation to the pathophysiological mechanisms underlying these various disease conditions. In IHD the high myocardial NA content creates local conditions for excessive NA release into the myocardial interstitium at the onset of ischaemia, which is known to result in several adverse local consequences.

Adult↗

Post-transfusion non-A, non-B hepatitis in Finland: a prospective study.

To study the frequency of post-transfusion non-A, non-B (NANB) hepatitis in Finland, we have followed prospectively 65 patients after open-heart surgery. The total number of transfused blood units was 652. Blood samples were obtained from the patients during the first 6 months after the operation and were studied for transaminase levels. The NANB diagnosis was based on exclusion of viral hepatitis of known etiology by serological tests for hepatitis A, B, cytomegalovirus and Epstein-Barr virus infections. We found three cases of post-transfusion NANB, all of which were subclinical and unicteric. The frequency of NANB hepatitis was 4.6%, and the proportion of infective blood units was 0.5%.

Adult↗

Taurine in human auricular myocardium and blood platelets.

Blood platelets have been used as a model for the aminergic neurones. In the hypertrophied left ventriles and platelets of spontaneously hypertensive rats the taurine content increases simultaneously. The main purpose of this work was to compare the taurine contents of human platelets and heart tissue. The taurine content was estimated from blood platelets and from the right atrial appendage removed during open heart surgery in 43 patients suffering from ischaemic heart disease. The results indicate that the taurine content increases in the hypertrophied right atrium of the patients with atrial septal defect, as it had previously been shown to increase in the hypertrophied left ventricle in patients who died of congestive heart failure. No correlations were found: 1) between the heart and platelet taurine contents of different groups, 2) between the atrial and platelet taurine in the pooled total results, 3) between the diastolic blood pressure and atrial or platelet taurine levels. Thus the increased taurine content of the auricular tissue is not reflected in the taurine content of the platelets.

Adult↗

The effects of a centrifugal pump as a left-ventricular-assist device in myocardial infarction.

Cardiogenic shock after acute myocardial infarction and open heart surgery having cardiopulmonary bypass may present a difficult clinical problem with high mortality. The present study was carried out to evaluate a newly developed laminar flow centrifugal pump as a left-ventricular-assist device to support the circulation and prevent myocardial damage in such situations. Experimentally induced acute myocardial infarction in dogs was used as the model. Cardiogenic shock was effected by ligating enough branches of the left coronary artery. In addition to recording the haemodynamic parameters, samples of myocardium were taken with a biopsy needle from the infarcted area, transitional zone and intact myocardium for determination of adenosine triphosphate, creatine phosphate and lactate. In the first phase of the work the effects of acute myocardial infarction on haemodynamics and high-energy compounds were defined, to form a basis for the evaluation of the pump as left-ventricular-assist device. Ligation of the branches of the left coronary artery produced a rapid fall in aortic pressure, cardiac output and cardiac performance, elevation of ST-segment in the ECG and fall in high-energy compounds. However, there was a marked spontaneous recovery in the transitional zone within 120 min, despite the haemodynamic deterioration. The laminar flow pump produced a significant improvement in the haemodynamic and metabolic parameters which exceeded the spontaneous changes noted previously.

Adenosine Triphosphate↗

Surgical treatment of coarctation of the aorta with minimal collateral circulation.

Twenty-four aortic coarctation patients with minimal collaterals were operated on. Left-side bypass was used in 18 cases, internal shunt in 4, while a jump graft ws inserted in 2 cases. These methods were applied when the distal aortic pressure fell below 50 mmHg systolic during test clamping. The coarctation was corrected with isthmusplasty in 12 cases, resection and end-to-end anastomosis in 5 cases, resection with prosthetic replacement in 5 cases and jump graft in 2 cases. The operative mortality was 2 patients (8.3%). One patient died of complications of a post-perfusion bleeding tendency; the other, who had concomitant aortic insufficiency, died of cerebral infarction and pneumonia. At follow-up examination, the blood pressure difference between the upper and lower extremities had disappeared in all cases. The blood pressure was still over 150 mmHg systolic in 9 patients, 8 of whom received anti-hypertensive medication. One patient died during the follow-up period, while waiting for an operation for aortic insufficiency.

Adolescent↗

Ischaemic cardiac aneurysms and ventricular septal defects. Surgical treatment with and without revascularization.

During the period 1968--78, 35 patients with left ventricular aneurysm after acute myocardial infarction were operated on at the Department of Thoracic and Cardiovascular Surgery, University Central Hospital, Helsinki. Twenty patients underwent resection of the left ventricular aneurysm and had coronary bypass grafting (Group I) and 15 patients had aneurysmectomy without revascularization procedures (Group II). Most of the patients (21) had the operation within one year after acute myocardial infarction. The aneurysm was located in the anterior wall in 31 cases and in the posterior wall in 4 cases. Three patients in Group II had a concomitant ventricular septal rupture, which was repaired simultaneously with the aneurysmal resection. In average, the patients in Group I had bypass grafting in 1.8 coronary branches. There were no intra-operative deaths. Three patients in the revascularization group died and 2 patients in the non-revascularization group died during hospitalization (15% hospital mortality). Two patients in the revascularization group and one in the non-revascularization group died during the average follow-up time of 3.4 and 6.4 years for the respective groups (late mortality 10 and 7%). The rest of the patients were doing well, including those with repaired VSDs. Follow-up coronary angiography was carried out of 12 patients; in 10 all the grafts were patent and in 2 one revascularized coronary branch had a patent graft. Revascularization produced apparent relief of anginal symptoms. Its beneficial effects on longevity remained unestablished.

Adult↗

Effect of combined cold and pharmacological ischaemic cardioplegia on myocardial intrinsic sympatho-adrenergic system during coronary bypass surgery.

The effect of combined cold and pharmacological ischaemic cardioplegia on the structural integrity and the degree of the functional activity of the inbuilt intrinsic sympatho-adrenergic nervous system was studied by means of fluorescence microscopy of atrial myocardial biopsies obtained in the course of coronary bypass surgery on 8 consecutive patients. The specimens were taken 1) before starting extracorporeal circulation (controls), and 2) at decannulation (i.e. after cold cardioplegic ischaemic asystole and subsequent coronary reperfusion). The cardioplegia was induced by perfusing the coronary arteries via the aortic root with cold "cardioplegic solution" after starting extracorporeal circulation, venting the left ventricle and cross-clamping the ascending aorta. The specimens were processed for semi-quantitative fluorescence histochemical analysis. No changes were observed. Thus, it is concluded that the procedure of the combined cold and pharmacological ischaemic cardioplegia obviously preserves well the neural noradrenalin of the heart, a vital means of compensating for decreasing myocardial contractility. As the clinical parallelism, all patients made a smooth convalescence.

Adult↗

Effect of cold ischaemic arrest and subsequent coronary reperfusion on the intrinsic adrenergic innervation and neural noradrenaline of the atrial myocardium during aortic valve replacement.

The effect of cold ischaemic arrest (aortic cross-clamping for 50-70 min during general hypothermia of +30 degrees C, associated with local cardiac cooling with +4 degrees C saline solution) and subsequent coronary reperfusion (20-30 min) on the intrinsic adrenergic innervation of the right atrial myocardium, was studied in 10 patients in the course of prosthetic aortic valve replacement using the glyoxylic acid-induced fluorescence histochemical method. No clear changes were observed: (a) the morphological integrity of the intrinsic adrenergic nerve net remained intact, (b) no obvious depletion occurred in the neural noradrenaline level, (c) the procedure did not affect the "droplet fibres" (i.e. huge axonal accumulations of noradrenaline). Thus, the common need for catecholamine support during and after weaning off from cardiopulmonary bypass does not seem to be explained by damage to the adrenergic axons or depletion of the adrenergic neurotransmitter noradrenaline.

Aortic Valve↗

Atrial acetylcholinesterase activity in various heart diseases of man.

Distribution and activity of the acetylcholinesterase enzyme in the human atrial myocardium was studied histochemically in a clinical series of patients subjected to cardiac surgery for (1) uncomplicated atrial septal defect (ASD), (2) ischaemic heart disease (IHD), (3) mitral and/or aortic valvular disease (VHD) necessitating replacement with a prosthetic valve, without major symptoms or signs of myocardial incompensation, or (4) clinically overt congestive heart failure (CHF) due to VHD prior to cardiac surgery. In all specimens, a rich distribution of acetylcholinesterase-positive single axons and small fascicles, constituting a three-dimensional nerve net, was observed within the myocardial tissue. This nerve net was obviously mainly parenchymatous, i.e. unrelated to the blood vessels. Small groups of acetylcholinesterase-positive small nerve cells were observed in some specimens, with loosely woven fascicles of axons emerging from one pole of the ganglia. No differences in the distribution of the acetylcholinesterase activity or in the pattern of the inbuilt intrinsic nervous apparatus were observed in the various groups of patients. All specimens were completely devoid of non-specific cholinesterase activity. It was concluded that (I) the human atrial myocardium is richly supplied with cholinergic intrinsic (post-ganglionic vagal) axons and (II) the acetylcholinesterase activity is not a major determinant of the parasympathetic abnormalities associated with cardiac diseases, especially with myocardial pump failure.

Acetylcholinesterase↗

ASD in patients over 40 years of age.

To evaluate the benefits of operative treatment of congenital heart disease in older age groups, a clinical study on patients over 40 years of age with atrial septal defect was carried out. The series consisted of 125 consecutive patients operated on between 1966 and 1974. There were 8 cases with a primum, 12 cases with a sinus venosus type of secundum and 105 cases with a simple secundum defect. The operative mortality was 2 patients (1.6%). It was due to myocardial infarction in one case and high pulmonary vascular resistance in the other. On re-examination 3-6 months postoperatively, 107 patients were improved, 13 patients unchanged and 3 patients were worse than before operation. On re-evaluation after an average period of 6 years, 88 patients were still improved. 32 patients unchanged and 3 patients were worse compared with their pre-operative status. On the basis of the results and the previous reports on atrial septal defect without operation, the surgical correction of ASD even in older age groups can be recommended. The problem of deterioration of some patients, despite a good immediate postoperative result, is discussed.

Adult↗

Auricular tyrosine hydroxylase and dopamine-beta-hydroxylase activities and noradrenaline content in ischaemic heart disease.

Assessments were made of the tyrosine hydroxylase (TH) and dopamine-beta-hydroxylase (DBH) activities as well as the noradrenaline (NA) content of samples excised from right auricular tissue during cardiac surgery on a total of 55 patients with ischaemic heart disease (IHD), valvular heart disease (VHD), uncomplicated atrial septal defect (ASD) or congestive heart failure (CHF). The NA content was significantly higher in the IHD group than in the other three groups. The TH activity was highest in the IHD group although the difference was statistically significant only compared with the ASD and CHF groups. The DBH activity was also highest in the IHD group, but again the difference was statistically significant only compared with the ASD and CHF groups. In the whole material there was a significant positive correlation between the NA content and TH or DBH activity, as well as between TH and DBH activity. In the IHD group there was a significant positive correlation between heart volume and TH activity. The results suggest that at least compared with ASD and CHF, the sympathetic tone is relatively high in IHD, possibly involving an enhanced NA turnover.

Adult↗

Human atrial noradrenaline content, hypothermic ischaemic arrest and parameters of left ventricular function.

The noradrenaline (NA) content in tissue excised from the right atrium before and after hypothermic ischaemic arrest and subsequent coronary reperfusion was estimated biochemically and histochemically. The series consisted of 22 patients suffering from aortic valve disease. The NA concentration in the preoperative and postoperative samples was similar in all instances and it was clear that the right atrial myocardial NA content remained unchanged under conditions typical of an aortic valve replacement operation. The mean NA contents (microgram/g +/- SD) of the whole series before and after procedure were 2.0 +/- 1.1 and 2.2 +/- 1.5, respectively (p greater than 0.1 NS). Additionally, left heart catheterization was performed preoperatively in 11 patients with aortic valve disease, and certain left ventricular cardiocirculatory variables of contractility and failure were recorded. No statistically significant correlation could be found between the right atrial myocardial NA content and the left ventricular contractile state. However, left ventricular end-diastolic pressure presented a significant positive correlation with the NA content of right atrial myocardium (r = 0.65, p less than 0.02, n = 11). The problems encountered in weaning the heart off perfusion after aortic surgery can hardly be explained in terms of altered myocardial NA stores.

Adult↗

Studies of auricular catecholamines by fluorescence histochemistry in various heart diseases of man.

A comparative histochemical and clinical study concerning the state of the intrinsic adrenergic innervation of the human atrial myocardium was carried out, using the glyoxylic acid-induced fluorescence histochemical method. Specimens from the right auricular appendage were obtained during open-heart surgery from patients suffering from 1. ischaemic heart disease (IHD), 2. atrial septal defect of the secundum type (ASD), and 3. left-sided univalvular or multivalvular heart disease (VHD) with or without congestive heart failure (CHF) experienced prior to surgery. In the IHD group the densities of both the perivascular and the "free" myocardial adrenergic nerve net were greater than in the ASD group and especially in the VHD/CHF group. Secondly, the intensity of fluorescence of the adrenergic structures was generally higher in the IHD group than that in the VDH/CHF group. Further, the average size of the varicosities, the number of varicosities per given length of axon, and the proportional share of the large varicosities were greater in the IHD group than in the ASD and VHD/CHF groups. The difference between the IHD and ASD groups was not great but was obvious in any case. In some patients with VHD/CHF fluorescing axons were observed only occasionally, and the tiny varicosities exhibited a hardly discernible fluorescence. Thus the amount of noradrenaline (NA) in the adrenergic fibres in the IHD group seems to be higher than in the ASD and especially VHD/CHF groups. The level of NA in the IHD group is assumed to constitute a contributory factor in both intracellular metabolic changes and the systemic changes typical of myocardial ischaemia and infarction. In one patient with IHD and in six patients with VHD/CHF with significantly higher heart volume (mean+/-SD) compared with the rest of the patients (P less than 0.001), huge local axonal accumulations of NA in the form of "droplet fibres" were found. These enlarged, bulging adrenergic axons are assumed to be a consequence of mechanical trauma with stretching or disruption of the axons due to myodegenerative processes. It is further assumed that these "droplet fibres" are relatively common in those patients with diseased myocardium. They may constitute an extra contributory factor to the tendency to arrhythmiility of non-atuomatic tissue.

Adult↗

Auricular catecholamine content in ischaemic heart disease.

The noradrenaline (NA) content (mean +/- S.D.) of tissue samples from the right atrial appendage in 19 patients with ischaemic heart disease (IHD) was 2.81 +/- 0.94 microng/g and in 7 patients with valvular heart disease (VHD) 2.79 +/- 1.12 microng/g. In 10 patients with uncomplicated atrial septal defect (ASD) the NA content was 1.64 +/- 0.32 microng/g and in 11 patients with congestive heart failure (CHF) 0.75 +/- 0.41 microng/g. The difference in NA content between the IHD group and the ASD and CHF groups is significant (p is less than 0.001). Small amounts of adrenaline and dopamine were found in all groups. There was no significant correlation between auricular NA content and either systemic diastolic blood pressure. The relatively high level of NA in the IHD group is assumed to be a contributory factor in the intracellular metabolic as well as in the systemic changes typical of ischaemia and infarction.

Adult↗

The effect of digoxin on the contractility of transplanted heart.

The effects of digoxin on the contractility of orthotopically transplanted heart was studied in dogs. Intravenously administered digoxin produced a fall in the rate and output of the transplanted heart without any change in stroke volume, whereas the output of the intact heart was slightly improved due to a small increase of stroke volume. This difference was thought to be due to the action of digitalis which is mediated via the nervous pathways, which are interrupted in the transplanted heart.

Animals↗

Fluorescence histochemical and electron-microscopical observations on the innervation of the atrial myocardium of the adult human heart.

The existence of both adrenergic and cholinergic innervation of the atrial myocardium of the adult human heart was demonstrated by means of fluorescence induced by formaldehyde or glyoxylic acid and by electron microscopy. The adrenergic fluorescing axons (1) followed the course of blood vessels as typical perivascular nerve plexuses, and (2) formed a three-dimensional fairly dense nerve net obviously not related to the blood vessels. The varicosities frequently came into close apposition on myocardial cells. Several types of nerve terminals were differentiated at electron microscopy: (1) an "adrenergic" type containing small (diameter 450-700 A) dense-cored vesicles and usually (in various proportions) small "empty" and/or large (900-1500 A) dense-cored vesicles, (2) a "cholinergic" type containing small (ca. 500 A) "empty" vesicles and occasionally also some large (mean diameter ca. 1200 A) dense-cored vesicles, (3) a "pale" type containing only a few or no vesicles, (4) a "disintegrated" type containing degenerated mitochondria, autophagic vacuoles, and occasional normal-looking mitochondria, (5) nerve terminals containing a large number of mitochondria in addition to varying vesicle populations, and (6) a (possibly baroreceptive type of) nerve terminal containing myelinlike lamellated structures. The "disintegrated" and the "pale" types of nerve terminals possibly represent different stages of axonal degeneration, or may correspond to diminution in the transmitter substance concentration under certain pathophysiologic conditions, respectively. Nerve terminals crowded with mitochondria may be sensory and involved in mechano-or chemoreceptive functions. In preliminary experiments convincing evidence was obtained that the glyoxylic acid-induced fluorescence histochemical method will be suitable for comparative studies on (human) clinical specimens, e.g., for analyzing the degree of the functional activity of the intrinsic adrenergic innervation of the myocardium under various pathophysiologic conditions. The modification which appeared most appropriate for such studies is described in detail, and is proposed for use as a standard method in other similar or related studies on human clinical series. The essential criteria for analyzing the specimens at fluorescence microscopy are suggested as well.

Adult↗

Histochemically demonstrable monoamine oxidase activity in the adult human heart in various cardiac diseases.

The present work was undertaken in order to study the role of monoamine oxidase (MAO) enzyme in the genesis of altered cardiac noradrenalin level in the human heart in various underlying pathologic conditions. The histochemical localization and the activity of MAO were studied in the right atrial appendage of man in ischemic heart disease, in valvular heart disease without or with congestive myocardial failure, and in hearts with an uncomplicated atrial septal defect. MAO was found to be localized mainly extraneuronally in the muscle cells, a little activity was detected in the connective tissue spaces, and nerves reacting positively were tentatively identified. There were no significant differences in MAO activity measured photometrically between the various heart disease groups. It seems that MAO activity measured photometrically between the various heart disease groups. It seems that MAO enzyme plays only a small or no role in the genesis of the latered noradrenalin level in the human heart observed in ischemic heart disease or congestive cardiac failure.

Adult↗