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Biomedical subjects

H J Herrmann

Publications and source records attributed to H J Herrmann.

At least 19 recordsLinked to original sources
PubMed1995

Pathogenesis of myocardial fibrosis in spontaneously hypertensive rats (SHR).

The pathomechanisms of myocardial fibrosis are incompletely understood. Coronary microvessels (MV), interstitial reactions and focal myocardial lesions characterized by morphological signs of ischaemia were found in 39 spontaneous hypertensive rats (SHR) and 33 control rats aged 3, 13, 27, 52 and 78 weeks, using new morphological preparations and measuring methods. In the developing phase of spontaneous hypertension (SH) the numerical and area densities (developed for up to 13 weeks) of MV were lower than at 3 weeks and lower than control. The same was true for the fibrotic tissue density. However, all values were increased in the manifest phase of SH (27-78 weeks). The increase in interstitial tissue is topologically and causally related to pathological MV reactions that represent morphologically chronically increased contractions. Small MV that mostly elude detection with conventional staining methods are of particular importance. The first phase of manifest SH (27th-52nd week) is characterized by a generalized development of myocardial fibrosis; the late phase (52nd-78th week) by a reinforced localized fibrosis that is attributable to the enhanced progression of focal ischaemic myocardial lesions. The septal region is not included in this phase. Thus, in the two phases of manifest SH, the pathomechanisms responsible for the development of myocardial fibrosis must be different.

Animals↗
PubMed1995

The sera of spontaneously hypertensive rats contain agonistic auto-antibodies against the beta 1-adrenoceptor.

OBJECTIVE: To examine auto-antibodies in the sera of spontaneously hypertensive rats (SHR) and investigate the possibility of abnormalities of the immune system in those rats. DESIGN: Blood samples were taken from 18-month-old SHR and age-matched Wistar-Kyoto (WKY) rats. The immunoglobulin fraction was prepared from the rat sera. METHODS: Immunoglobulins were investigated in a sensitive biological test system using spontaneously beating neonatal rat heart myocytes. RESULTS: Immunoglobulins prepared from the sera of the 18-month-old SHR increased the beating frequency of cultured rat heart myocytes. This positive chronotropic effect induced by the auto-antibody-containing immunoglobulin fraction was realized via the beta 1-adrenergic receptor. CONCLUSIONS: The sera of the investigated ageing SHR contain agonistic auto-antibodies directed against the beta 1-adrenoceptor. These anti-beta-adrenoceptor antibodies in the SHR, like those in the sera of cardiomyopathic patients, recognize in most cases the second extracellular loop of the beta 1-adrenoceptor as the site of the antigenic determinant, and act in a similar way to the antibodies observed in the sera of cardiomyopathic patients. The present findings provide the opportunity of using ageing SHR as a model to investigate the development and possible pathogenic role of the agonistic auto-antibodies that recognize the beta 1-adrenoceptor.

Animals↗
PubMed1993

Automated histomorphometry of interstitial reactions in the heart.

A method is presented suitable to measure changes in area densities of the total Sirius red-stained interstitial tissue in longitudinal sections of rat hearts by means of computer-aided image analysis considering at the same time the behavior of six regions and changes in the percentage of thick connective tissue fibers in the total interstitial tissue. Verification tests were directed to the influences of preparation, adjustment of the grey-level thresholds, and identification of the various regions, to marginal conditions of measurement and the investigators. The reliability of the method with acceptable total errors is demonstrated.

Animals↗
PubMed1992

Histomorphometry of focal myocardial lesions by means of the automatic image analysis.

There is an urgent necessity to objectify focal myocardial lesions (fml) before structural changes in muscle cells can be seen light microscopically. Therefore the succinodehydrogenase (SDH) reaction was chosen because it reliably demonstrates the decrease in aerobic capacity already in structurally unchanged cells and distinguishes the latter from the SDH-negative structures. A combined planimetric and densitometric procedure was developed to measure the area density of fml and their 2 constituents mentioned as well as to evaluate the SDH activity in fml and its decrease in muscle cells using the automatic image analysing system QUANTIMET. The verification tests show that both the area density and extinction can be reliably determined with acceptable measuring errors unless the area density is too low. The results of interobserver and repeatability tests are satisfying.

Animals↗
PubMed1992

Structural wall tissue alterations of the microvasculature in the course of spontaneous hypertension of rats.

The existence of structural reactions of the microvasculature of spontaneously hypertensive rats (SHR) and the underlying causal mechanisms are generally controversially discussed. Ninety-two male SHR aged 3-52 weeks and 118 normotensive age and sex matched controls were investigated. A new histomorphometric procedure was applied that ascertains structural changes in microvessels with diameters below 9 microns, between 9 microns and 19 microns and above 19 microns in anatomically defined sections of the skeletal muscle, heart and pancreas. Significant rises in the numerical and area densities of microvessel surfaces document a pathological increase in wall tissue of the microvasculature in all 3 organs and stages of spontaneous hypertension, with the exception of the coronary microvessels of 8-16 week old SHR where this progressive structural reaction was antagonized. How far the hypertrophy of the microvascular wall tissue is connected with an increase in wall thickness disproportional to the corresponding lumen wideness remained unknown. A positive correlation between the increase in blood pressure and wall tissue was only substantiated in the pancreas microvasculature. The generalized preferential occurrence of pathological reactions in vessels with diameters below 19 microns in the early established phase indicates that the microvascular control changes in this phase of spontaneous hypertension (SH).

Animals↗
PubMed1989

[Does the cardiogoniogram change following revascularization?].

19 patients with one-vessel coronary disease were studied by cardiogoniometry (CGM), a new computerized vectorcardiographic method, before and after revascularization. In 14 patients revascularization had been performed by the method of percutaneous transluminal angioplasty (PTCA) and in 5 patients by aortocoronary bypass operation. Although the majority of cases showed a good postoperative result, CGM parameters failed to demonstrate a significant change, i.e. a previous pathologic CGM remained unchanged. It therefore appears to be doubtful whether CGM is reliable enough to assess the results of revascularization, possibly because it is more sensitive to infarcted than potentially ischemic yet vital myocardium.

Angioplasty, Balloon↗
PubMed1989

Progress in the histomorphometry of the microcirculatory system.

Following a short review of the limits set to the procedures applied so far to measure quantitative changes in wall tissue of microvessels, a new measuring method is presented. It detect morphological reactions of the microcirculatory system on the grounds of changes in the numerical density of selectively visualized microvessels and their classification according to the external diameter by means of the automatic microscopic image analysing system QUANTIMET. Influences of structurally based and/or postmortal changes of the lumen wideness on the measurement are excluded by the automatic subtraction of the lumen area.

Animals↗
PubMed1989

Progress in application of the image analysing system QUANTIMET 720 in the histomorphometry of the microcirculatory system.

The application of automated image analysing methods in the field of histomorphometry has been improved in the last decades. In this paper a new method is presented for the investigation of morphological reactions of the microcirculatory system. It is based on the measurement of quantitative changes in microvessel wall tissue by using the image analysing system QUANTIMET 720. In the measurement model, a microvessel intersection figure is considered as an ellipsis. A procedure is presented allowing the estimation of the wall and lumen area of the microvessel section and the calculation of its radius for a totally collapsed state. From this data, further morphometric parameters are derived. Using this method, the analysis of 500 microvessels including classification and parameter derivation takes about 10 min.

Algorithms↗
PubMed1987

Comparative diagnostic value of a new computerized vectorcardiographic method (cardiogoniometry) and other noninvasive tests in medically treated patients with chest pain.

The diagnostic value of cardiogoniometry (CGM), a new computerized vectorcardiographic method, for the identification of coronary artery disease was compared with other noninvasive tests in 48 medically treated patients with chest pain. Coronary angiography revealed one-vessel disease in 18, two- or three-vessel disease in 21, and normal coronary arteries in 9 patients. Cardiogoniometry was less sensitive (63%) than thallium-201 (201T1) scanning (82%), but slightly more sensitive than the exercise ECG (50%) or a recently proposed parameter of exercise performance (50%). On the other hand, specificity was comparable among these tests (exercise ECG 78%, thallium-201 scanning 72%, CGM 67%, new parameter of exercise performance 66%). Moreover, the false negative rate of noninvasive testing was reduced from 8 to 3% when CGM was added to thallium-201 scanning and exercise ECG. Our findings indicate that in view of the easier feasibility with computerized technology, the future role of vectorcardiographic methods such as CGM in the noninvasive diagnosis of coronary artery disease should be redefined.

Adult↗
PubMed1987

Effects of quantitative undernourishment, ethanol and xylene on coronary microvessels of rats.

The effect of alimentary deficiency, ethanol intake and exposure to xylene on the coronary microvessels and heart weight were investigated in rats. The coronary microvessels of rats, which were undernourished for 5 weeks and which were fed ad libitum were studied with the histomorphometric method of Herrmann et al [19]. In another experiment a group of rats was fed a control liquid diet while another group was fed a liquid diet containing ethanol up to 36% of the total Joule intake. One-half of both groups were placed in an exposure chamber supplied with pure air; the other two half-groups were made to inhale air containing 1000 mg xylene/m3 for 6 h daily, 5 days a week, for a period of 4 weeks. It was found that undernourishment did not cause any morphological reactions in the microvessels and did not affect the relative heart weight. Ethanol increased the contractile activity of the wall cells of coronary microvessels, and also the relative heart weight. The effect of xylene was similar to that of the ethanol. The effect of xylene in combination with ethanol was additive on the one hand (in some parameters), on the other hand there was an inhibition between the effects of the two chemicals (in the case of the number of mv. 10.5 micron less than d less than 21 micron). It is concluded that both ethanol and xylene increase the vascular tone of coronary microvessels and this alteration causes a decrease in the nutritive myocardial blood flow. Undernourishment does not play any role in the increase of vascular tone.

Animals↗
PubMed1987

Peculiarities of adriamycin cardiotoxicity in spontaneously hypertensive rats (SHR).

The adriamycin (ARD) effects on the myocardium and the microcirculatory system (m.s.) of the heart and the skeletal muscle were studied enzyme histochemically and histomorphometrically. Normotensive Wistar rats (ADR-NWR) and SHR (ADR-SHR) were given 3 weekly intravenous injections of 1 mg ADR/kg b.wt. Controls were injected with saline. Besides the well-known ADR-induced single-cell degeneration observed in both strains, ADR-SHR have developed focal myocardial lesions (f.m.l.) to be characterized as ischemic alterations. Their number and size have distinctly increased as compared to saline-treated SHR. In the coronary m.s. the ADR applications were followed by signs of structural adaptation to chronic contractions, especially in ADR-SHR and within the f.m.l. The latter were considered to be decisively engendered by the pathological reactions of the m.s. In ADR-SHR possible the cardiotoxic ADR actions have aggravated these microvessel reactions and their consequences.

Animals↗
PubMed1987

Hypoxia-induced regression of adaptive structural microvessel reactions caused by long-term contraction influences in spontaneously hypertensive rats (SHR).

Chronic effects of hypobaric hypoxia (hb.h.) on the microcirculatory system (m.s.) of skeletal muscle were investigated. A new histomorphometric method was applied to detect the adaptive structural reactions of wall cells to long term changes in contraction performance. Seventeen SHR were exposed to hb.h. from 5 to 18 or 17 to 30 weeks of life, respectively. For controls 19 SHR and 25 normotensive Wistar rats were kept at sea level. The findings document long-term actions of vasorelaxation factors in hb.h. and the ability of the latter to antagonize the intensified vasocontraction factors in SHR. Depending on the stage of hypertension, there are different preferential sides for the actions of both these factors within the various districts of the m.s.

Adaptation, Physiological↗
PubMed1987

Preventive dental care: the role of the pediatrician.

The pediatrician can assist the dental profession in preventing dental disease and maintaining the oral health of children. Pediatricians are urged to counsel parents in dietary and oral hygiene practices that will prevent dental caries and to refer patients for professional dental care when appropriate. Systemic fluoride supplements should be prescribed when needed but only after a careful review of requirements and daily consumption.

Adolescent↗
PubMed1984

Long-term effects of psychoemotional stress and tread-mill exercise on the microcirculatory system of rats.

To answer the question of whether the increased intensity of tonic or of relaxing influences acting on the microcirculatory system predominate in various chronic psychoemotional stress situations and/or after long-lasting and intense tread-mill exercise, the left-ventricular wall of the heart and the skeletal muscle or pancreas of 49 experimental and 33 control animals were investigated, using a new histomorphometric method. Chronically stressed rats showed an increase of wall thickness in microvessels documenting a long-term increase of contractile performance of wall cells for the development and maintenance of an increased contractile tone; however, there were quantitative differences depending on the manner, intensity, and duration of stress. The opposite occurred in rats exercised by a tread-mill over 6 months, 3 h per day, demonstrating the morphological correlative of metabolic long-term autoregulation. An aversion stress applied simultaneously on these animals effectively antagonized the mentioned effects of exercise.

Animals↗
PubMed1984

Long-term effects of ethanol on coronary microvessels of rats.

To study the hitherto unknown long-term effects of ethanol on the contractile activity of wall cells of coronary microvessels (mv.), 21 experimental and 21 control animals were investigated, using a new histomorphometric method. The pair-fed rats of the experimental group were given a diet containing ethanol which replaced 36% of the total calories for 4 weeks. This resulted in an increase of wall thickness of mv. in all segments of the microvasculature and an augmentation of the number of ATP-hydrolyzing small-calibered mv. The increase of wall thickness of muscularized mv. was interpreted as a structural adaptation to a long-term predominance of vasotonic influences, which were apparently likewise responsible for the increase of ATP-hydrolysis in the smallest mv. The possible reasons for this predominance are discussed and the necessity to include myocardial metabolic factors in pathogenic considerations on ethanol-induced coronary affections is indicated. Such mv. reactions as observed may be considered as a potential contributive pathogenic factor in ethanol-induced cardiomyopathies and hypertension.

Adenosine Triphosphate↗
PubMed1983

[Giant cell reaction of short tubular bones].

This paper deals with the case of a so-called giant-cell reaction of the short tubular bones of a 31 year-old patient. Histologically, this rare benign disease falls under the category of tumor-like lesions of the bone. Clinically, the disease becomes evident through pain and swelling, and radiologically, a lytic bone process can be observed which may well perforate the cortical substance. The therapy consists in the total removal and the filling of the defect with autologous bone graft from the iliac crest, in some cases also by means of some additional autologous cancellous bone chips. The prognosis after surgical therapy is excellent. In the few cases which have to date become known, no cases of recurrence have been observed. Although the pathogenesis has not been clarified, thus far trauma and local disturbances of growth and/or development must be considered. Concerning differential diagnosis, one should distinguish above all the reaction from aneurysmal and juvenile bone cyst, as well as osteoclastoma.

Adult↗
PubMed1982

[Morphologic reactions and long-term vasal tonus behavior of the coronary microvascular system in different states of spontaneous hypertension in the rat].

The morphological reactions and the long-term vasotonus behaviour of the coronary microvasculature including its smallest ramifications as well as the relationships existing between these reactions and the myocardial activity in the different stages of spontaneous hypertension of rats (SHR) are unknown. Therefore 80 1-12 month-old male SH- and 60 normotensive Wistar control rats were histomorphometrically investigated. Already in the prestage of hypertension (1 month) an increase of wall thickness and phosphatase activity in blood vessels alpha less than 10,5 microns occurred. These appearances of vasotonus increase were regressed in the acute phase (2nd-4th month). When the rise of myocardial activity is lowered in the stabile stage the mentioned signs of vasotonus increase returned (6th month) and showed a strong spreading in the late stage (12th month), which is characterized by enzyme histochemically detected disturbances of heart muscle metabolism. The behaviour of long-term vasotonus of the microvasculature and myocardial metabolism in 6 month-old and older rats provides a hypothesis concerning the cause of the unknown increase of coronary contraction in the stabile phase. It points to the existence of a vicious circle which perhaps plays a role in the genesis of heart insufficiency in hypertension.

Animals↗