Bundle branch reentrant tachycardia in a patient with a calcified bicuspid aortic valve and normal ventricular function.

We report the case of a bundle branch reentrant tachycardia (BBRT) in a 40-yearold patient with a calcified bicuspid aortic valve and normal left ventricular function. The ventricular tachycardia was eliminated by successful radiofrequency ablation of the right bundle branch. As the aortic valve annulus is in close proximity to the specialized conduction system, premature degeneration of a bicuspid aortic valve may involve the bundle of His and the proximal bundle branches by invading calcifications. We speculate that calcifications invading the proximal bundle branches from the bicuspid aortic valve may have created the substrate for the BBRT in this patient.

[Time and temporality in gerontology and the ontologic privation theory of biological aging]. / Zeit und Zeitlichkeit in der Gerontologie und die ontologische Privationstheorie des biologischen Alterns.

We have seen how our conception of time has changed in the course of the years. Up to the beginning of this century people believed in absolute time. According to today's views, time and temporality do not consist of a continuous flow of time successions, as generally assumed, the essence lies in the inner character of events. Therefore, in order to comprehend the true nature of time and temporality in gerontology, we must pay particular attention to the constitutional structures of events or happenings. Here we must comprehend the implication of an ontological change and the constitutions of time as metaphysical structure. Time and temporality are measured in happenings and processes, and not vice versa. Whitehead, showed that we are concerned with an ontological interpretation of time and temporality. The biodynamics of an individual reveal the largely autonomous structure and bionomy of the processes of life, as well as the continuous interaction and shifts of the biological cycles of formation, change, and decline. The ontological privation of biological aging and death are just as much a part of life as conception and birth. Only what lives can mature, age, and die. The imminent "purpose" of the biological aging of the individual is dying and death, i.e., the return home into "absolute being".

On the ontology of biological aging.

The central question in the field of experimental gerontology is: what is biological aging? It is true that a living body must obey the laws of causal determinism; like all bodies it is subject to the physical and chemical laws of the phenomenal world. But there is a further aspect; as well as the finality which unites the part, the organism and the organ, there is also a metaphysical meaning at work in life.

The propensity of biological aging.

From birth to death life represents a structural connection of events, regardless of the space of time separating them. The potentiality of a living system is a finite one. It can only be finite since infinity cannot be achieved by a progression of finite elements. Ontogenesis then ends when the potentiality of the organism is fully realized and has reached an optimum, the highest level of bionomical order (Kment, in prep.), which corresponds to the vitality maximum (Beier, 1980). In attacking the problem of probability statements in their most general form, Popper (1959) developed the "propensity interpretation of probability". In my opinion, the disposition towards aging, or, in other terms, the propensity of biological aging, also has to be regarded as a reality--as a biological reality. Since the propensity of aging is viewed as a measure of a disposition, we also have to deal with two questions in order to accept it as a biological reality: Is there any measure of biological aging which can be defined operationally? Is there an operational definition possible of the propensity of biological aging? The acceptance of the concept of propensity in biomedical gerontology, will make it necessary to comment anew on the unsolved problem of a general definition of aging.

Contractile, coronary, and metabolic effects of the acute and long-term treatment of cardiac failure with prenalterol.

Prenalterol was examined with regard to its acute intravenous effects on left ventricular function, coronary hemodynamics, and myocardial oxygen consumption, as well as for its long-term effects, by oral therapy, on left ventricular function and systemic hemodynamics. Intravenous prenalterol enhances myocardial contractility and left ventricular ejection function significantly. A decrease in total peripheral vascular resistance is effected. Myocardial oxygen consumption is only moderately increased, most probably because of the decrease in the systolic integrated wall stress of the left ventricle. The changes of coronary circulation (blood flow, resistance, arteriovenous, oxygen difference) indicate benign and metabolically induced coronary vasodilation. Long-term oral treatment of patients with severe cardiac failure by prenalterol effects significant enhancement in-left ventricular performance within the first 1-2 months of treatment; however, this effect is not present at longer therapy intervals (16-28 weeks). Tolerance development as well as the natural history of these patients may be responsible for this inotropic amelioration. There were no clinical side effects with either intravenous or oral application. It may be concluded that prenalterol is highly effective in acute cardiac failure (intravenous administration) and also in chronic heart disease (long-term oral application). However, the long-term effects are unpredictable, and tolerance development has to be considered.

[Myocardial 201-thallium uptake after hydralazine in coronary disease]. / Myokardiale 201-Thallium-Speicherung nach Hydralazin bei koronarer Herzkrankheit.

UNLABELLED: Following injection of hydralazine, a benign coronary-artery-dilating drug, myocardial blood flow increased by 25%. Myocardial 201-thallium uptake at rest and after intravenous injection of 12 mg hydralazine was quantitatively investigated in 28 patients. In patients with essential hypertension or coronary artery stenoses of up to 90%, myocardial 201-thallium uptake increased by 19%-30% in nonischemic areas. In 9 of 14 patients with regional imaging defects, thallium uptake also increased in these ischemic areas; 4 of these patients had asynergies in the area of imaging defects. In 3 patients with a complete obstruction of a major branch of a coronary artery perfusion defects developed following hydralazine application. CONCLUSION: An increased 201-thallium uptake in an ischemic area indicates reperfusion; this could be helpful for deciding whether coronary surgery should be performed or not.

[The influence of persistent crowding on the spontaneous motor activity of the aging rat (author's transl)]. / Der Einfluss anhaltend erhöhtr Populationsdichte auf die Spontanaktivität der alternden Ratte.

In the course of a long-term cohort study of stress and aging, the spontaneous activity of 169 male Sprague-Dawley rats was measured at various ages from 9 to 30 months. 84 animals were submitted to crowding from the age of 5 months onwards by housing them in groups of 12 per Makrolon-IV cage. 85 rats, kept as usual in groups of 6 per makrolon-IV cage, served as a control. Spontaneous activity was assessed by an electronic instrument (Animex Activity Meter), which also enabled us to distinguish between total and large movements. During senescence, the spontaneous activity of the control animals decreased slightly by approximately 20% after the age of 18 months. In addition to the quantitative change, a progressive flattening of the activity rhythm was observed. The animals kept under crowded conditions did not reveal any age-related decrease in spontaneous activity. At an advanced age, this resulted in significantly higher activity values in the crowded group as compared with the controls. The differences appeared even earlier and seemed to be more pronounced in the number of large movements. However, the progressive disappearance of the endogenous rhythm was apparent in both the crowded and the control group. It can be concluded that at least two types of change in the central nervous system may be responsible for the aging-changes in spontaneous activity: one which disintegrates the "time structure" of the organism, and a second one which affects motivational centers. Crowded conditions seem to improve the latter, whereas they have no effect on the aging of the "biological clock".

Elevated angiotensin-I-converting enzyme (ACE) in patients with essential hypertension.

We investigated the alteration of the ACE in different parts of the circulation in 21 patients with essential hypertension, who suffered from angina pectoris attacks. Blood samples were taken during diagnostic cardiac catheterisation. The ACE was fluorimetrically measured and compared to 48 normotensive patients. In 11 patients the Plasma Renin Activity (PRA) was additionally determined by means of bioassay. The ACE was significantly (p less than 0.001) elevated in all investigated regions but a different distribution was not observed. We found a positive correlation between the ACE from the left ventricle and the systolic, mean arterial and diastolic blood pressure. Furthermore, we observed a negative correlation between ACE and PRA. No relationship could be calculated between ACE and electrolytes, creatinine or haemodynamic parameters. Our results indicate that the ACE may contribute to the pathogenesis of so-called essential hypertension.

[End-diastolic volumes of the left ventricle in computer tomography in comparison to heart catheter ventriculography]. / Das enddiastolische Volumen des linken Ventrikels in der Computertomographie im Vergleich zur Herzkatheterventrikulographie.

In 47 patients the authors calculated the volume at the end of a diastole according to both the cardiac catheter ventriculogram and the CT ventriculogram, comparing the results obtained with each of these methods. A linear regression was found. The correlation coefficient was approximately r = 0,96; n = 47. Cardiological examination revealed that of the examined patients (including the cardiac catheter finding) 18 patients had coronary heart disease, whereas 9 had cardiomyopathy, 6 arterial hypertension, 9 had various cardiac abnormalities and 5 did not show any organically manifest heart disease. The article discusses CT determination of the volume at the end of the ventricular diastole, and discusses the results.

[The model in experimental gerontology (author's transl)]. / Das Modell in der experimentellen Gerontologie.

In experimental gerontology as a biomedical science, the knowledge and understanding of aging is expressed in hypotheses, theories and models. In this context, the model turns out to be a specific criterion of a definite level of abstraction. The general concept of models comprehends three characteristics: illustration, reduction and pragmatism. Every model is an approximating attempt to comprehend reality. In experimental gerontology various kinds of models can be used. This variety is necessary result of the variety of methods used in this field of science. Any reductionism would imply a restriction, limitation and rigidity. The final aim of experimental gerontology should be the evaluation of a universal dynamic model of aging which is valid for any aging process in biological systems.

[Aspects of stress and aging in the rat (author's transl)]. / Aspekte von Stress und Altern bei der Ratte.

Sprague-Dawley rats aged 6 to 22 months were stressed for 2, 16 and 9m resp. by the influence of noise (106 dB, 2h/d) and overcrowding (12 rats/Makrolon-IV-cage). Parameters of the plasma, brain, testicles and the liver (enzymes, metabolites and hormones) and well-known age parameters were evaluated to obtain objective criteria for stress influences. The weights of the whole body and some organs were also measured. The most distinct changes were seen in the plasma enzyme activities CPK, ALD, CHE and AP, in the concentrations of CHO and TRG and in the levels of testosterone, corticosterone and aldosterone. The contraction-relaxation of the tail tendon and the soluble collagen of the corium changed in the direction of higher age, just as lipofuscine content in the brain, cerebellum and the adrenals did. Some activities of enzymes and concentrations of metabolites changed in the brain, liver the testicles. Adrenal weights rose sharply in both stress groups; the body weight was lower. There were some differences in the effects of the two stress factors. These investigations gave some information about the relation between stress and aging and provide a simple means of determining the influence of stress.

[Gerontological pilot study on learning ability and memory in the stressed rat (author's transl)]. / Gerontologische Orientierungsstudien zum Lern- und Merkvermögen der Ratte unter Stressoreneinfluss.

The influence of noise and overcrowding on the learning ability and memory was investigated during a long term cohort study in 120 male Sprague Dawley rats covering an age range from 8 to 14 months. The investigations were performed by means of a semi-automatical multiple-T-maze with 7 choice points. The results showed that noise and overcrowding enhanced the learning ability and memory in rats up to an age of 10 to 12 months. However, the learning ability and memory were declining faster with age in the stressed animals than in the unstressed ones. The stressor "overcrowding" proved to be more effective than the stressor "noise" applied by the authors.

[Discriminant analysis of age parameters of the rat (author's transl)]. / Diskriminanzanalyse von Altersparametern der Ratte.

The capacity of age parameters to discriminate between groups or individuals of different biological age was investigated in the course of a long-term cohort study. 23 age parameters measured in 71 male Sprague-Dawley rats at the ages of 10, 17, 25 and 30 months, were submitted to a stepwise discriminant analysis. An optimal simultaneous discrimination between the four age groups was obtained by 3 discriminant functions with scores of 89.8%, 6.2% and 4%, with a correct classification of 98,6% of all individuals. Three analyses of successive age groups (10--17, 17--25, 25--30 months) resulted in a 100% correct classification by one function each. However, it turned out that in different phases of senescence an optimal discrimination between individuals or groups of different biological age is obtained by distinct combinations and weights of the parameters.

[Problems of the assessment of biological age (author's transl)]. / Probleme der Messung des biologischen Alters.

Biological age may be defined at the state of the organism as a whole which is characteristic of the respective chronological age. Usually, it is estimated by multivariate analysis of a battery of age parameters. However, this procedure requires the knowledge of the regularities of multicellular ageing since interferences about the behaviour of the total system from its subsystems may only drawn when the regularities of the total system are understood. By means of the ageing of the rat, the possibility is demonstrated to study these regularities by factor analysis. As a result, primary and system-specific secondary aging processes are postulated which are expressed to various extents in the individual age parameters.

Models of the biological age of the rat. II. Multiple regression models in the study on influencing aging.

The study of influences on multicellular aging requires mathematical models of biological age (BA) as a standard against which deviations from "normal aging" can be measured. A long-term cohort study with initially 1100 male Sprague-Dawley rats served to establish multiple regression models of BA and to test the effects of fast days, physical training, a combination of fast days plus physical training, and the long-term action of subcutaneously applied lyophilized heterologous fetal testis material. All influences started after the attainment of maturity. The models were calculated on the basis of an exponential decrease in vitality during senescence. Twenty-three parameters from a total number of 42 were selected for a general model. By means of a factor analysis, the general model was subdivided into five factor models of BA to distinguish between primary and various types of secondary aging changes. All experimental conditions showed clearly detectable but not dramatic effects on the general model of BA in the sense of a revitalizaion. The most pronounced effect was found in the group pretreated with testis lyophilisate. The results obtained with the factor models suggest that this effect might be due to influences on primary aging as well as on some secondary changes.

Models of the biological age of the rat. I. A factor model of age parameters.

The hypothesis of biological age postulates a fixed pattern in the aging of the multicellular organism. As a test of this hypothesis 23 age parameters of the rat were submitted to factor analysis. The data used in this study were a result of a long-term cohort study on 240 male Sprague-Dawley rats, which covered an age range of 10-30 months. The age parameters were obtained from various systems and levels of organization. The analysis revealed that there is a fixed pattern in the variations of the parameters. In this factor pattern the parameters are grouped into six factors, five of which can be attributed to the aging process. The first factor is interpreted as representing primary aging, factors 2-5 are interpreted as an expression of system-specific secondary processes of multicellular aging. Approximately 40% of the total variation of all parameters turned out to be random or due to processes other than aging.

[Perspectives in experimental gerontology (author's transl)]. / Perspektiven der experimentellen Gerontologie.

Experimental gerontology is changing progressively from an idiographic (descriptive) science to a nomothetic (conceivable in terms of laws) one. Besides the punctual studies of the total complex of aging, those investigations will acquire increasing significance which take into account the bionomal character of life. In addition, the views of logic science, epistomology and system theory will be employed in experimental gerontology more often than is the case now. Experimental gerontology will finally lead to the development of a theoretical gerontology.