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Biomedical subjects

W Hort

Publications and source records attributed to W Hort.

At least 37 records · Page 2Linked to original sources
PubMed1995

[Quantitative light and electron microscopy studies of myofibrils and mitochondria of dog and chicken hearts].

Ventricular myocytes are characterized by a central nucleus which is surrounded by longitudinal myofibrils and a mostly column-like longitudinal distribution of mitochondria. This study was designed to investigate the subcellular distribution of organelles in close proximity to the nucleus. Of particular interest was the question of whether volume density of organelles close to the nucleus is maintained and, as a consequence, if the cellular diameter at the site of the nucleus is increased according to the dimension of the nucleus. Therefore, dog and chicken hearts were subjected to perfusion fixation and sections of myocytes were studied in longitudinal and cross-sectional axes by light and electron microscopy. Volume density of organelles was analyzed on longitudinal sections according to Rosiwal's principle and on cross-sections by the point-counting method and a digitalized imaging system. We found that the cross-sectional diameter of cardiac myocytes is slightly wider at the site of the nucleus according to the dimension of the nucleus. The volume density of myofibrils and mitochondria is similar in most subcellular fractions except at the nuclear poles where mitochondria were significantly more abundant. Thus, no significant disturbance of the organelle distribution is observed at the site of the nucleus.

Animals↗
PubMed1995

[An interventional study against cigarette smoking among Dusseldorf high school students 1992-94].

Between 1992 and 1994, an interventional program was held in the secondary schools ("Hauptschulen") in Düsseldorf contra cigarette smoking. The program was conducted in the following way. Half of the schools (intervention schools) were involved in this program which consisted of 15 sessions. The other schools served as control groups. During the first year of this program school-teachers and a physician taught students about the function and the abilities of the healthy heart and lung. The students developed adversions to smoking. In addition, the students learned by role-plays how to say no to a cigarette without embarrassment. These role-plays were videotaped. During the second year of this program the role-plays were repeated and teaching about the heart and the lungs was augmented. Also, every student got the opportunity to meet and talk with a famous athlete. Furthermore, smoking-cessation programs were hold in four intervention schools. The program started in the sixth grade with a questionnaire administered to 878 schoolchildren. During this time the average age of the children was 13 years. Because of a large fluctuation, the questioning could be repeated with only 630 of these children (71.8%) after 2 years. At the end of the study the number of smokers had increased two times greater in the control schools than in the intervention schools (boys: 20.5% points vs 9.4% points; girls: 44.3% points vs 21.0% points). Obviously, the continuation of the program during the second year was important in making the program successful. Among the participants of the intervention program there was a trend to stop smoking. But the program was not able to prevent non-smokers from starting the habit. On the other hand, of the children who started smoking during the program, more girls in the intervention schools quit smoking than in the control schools. At the end of the program more girls than boys (mean age 15 years) smoked. Almost one-fourth of the boys, and from the control schools one-third of the girls were already daily smokers. The smokers obtained cigarettes from kiosks, from friends, vending machines, vendors or shops, but seldom from their homes.

Adolescent↗
PubMed1994

Arteriosclerosis: its morphology in the past and today.

In a brief historical review the contributions of Rokitansky, Virchow, and Langhans concerning the pathogenesis of arteriosclerosis and the histogenetic puzzle of intimal cells classification are described. Then, some unresolved problems are discussed, especially the localization and distribution of arteriosclerotic plaques, the shape of endothelial cells and the orientation of their nuclei in correlation to local hemodynamic stress under normal and pathologic conditions. Some differences between experimental arteriosclerosis and arteriosclerosis in humans are illustrated by examples. The key role of the endothelium in the development of arteriosclerosis is well founded. According to recent investigations some cells on the surface of human arteriosclerotic plaques appear to be of non-endothelial origin. Arteriosclerosis seems to be a systemic disorder with multiorgan involvement. Individual cases, however, show significant differences in the distribution and extent of lesions. Today, arteriosclerotic research is focused on arteries being most important in clinical investigations. Nevertheless, there are also other arteries with severe arteriosclerotic lesions; for example, the degree of arteriosclerosis in periprostatic arteries is more pronounced than in coronary artery branches of the same size. Finally, the importance of primary prevention of arteriosclerosis is emphasized.

Animals↗
PubMed1992

Intimal fibrosis (phlebosclerosis) in the saphenous vein of the lower limb: a quantitative analysis.

The influence of pre-existing phlebosclerosis on the patency rate of aorto-coronary bypasses is uncertain. To examine this influence, extensive quantitative histological investigations of the intimal thickness of the left saphenous vein were made in 30 cases. In almost all veins the intima was thickened by collagen and elastic fibres as well as by fusiform cells which were assumed to be smooth muscle cells. The innermost layers also contained increased collagen adding to the intimal thickening. Three different methods to measure the intimal thickness were tested morphometrically: planimetric, a four-point method and a so-called method of estimate. The latter is the most time-saving and effective method. The average intimal thickness showed considerable deviations, but the intimal thickness in individual veins did not deviate greatly. As a rule, a specimen with an intimal thickness of less than 100 microns belonged to a vein with mild or moderate intimal thickening, but specimens with an average intimal thickness of 100-250 microns usually derived from a vein with moderate or pronounced intimal fibrosis. However, extreme values allowed a more precise statement to be made. A specimen with a nonsclerotic intima suggested at best a mild intimal fibrosis of the vein in the lower limb, whereas a specimen with marked intimal thickening derived from a vein with severe phlebosclerosis.

Female↗
PubMed1992

Malignant fibrous histiocytoma of the heart--case report of a rare left-atrial tumor.

The present report describes the case of a 57-year-old patient with malignant fibrous histiocytoma of the left atrium operated on for a suspected atrial myxoma. Surgery was performed as radically as possible and included resection of the atrial wall. Clinical investigation and echocardiography performed 29 months after surgery revealed no signs of tumor recurrence. Diagnostic procedures, topography, pathohistology as well as options for therapy are discussed with regard to the latest literature. A radical surgical approach represents the only effective therapeutic measure. Owing to a lack of sufficient experience, there is no additional therapeutic recommendation on hand. Neither radiation nor chemotherapeutic treatment concepts have proved efficient. Echocardiography represents the best examination procedure for both diagnosis and follow-up in patients with cardiac tumor.

Heart Atria↗
PubMed1992

[Dysplastic intramyocardial arteries with subaortic septum in patients with hypertrophic obstructive cardiomyopathy].

Abnormal, dysplastic intramyocardial arteries were reported in autopsied hearts of hypertrophic cardiomyopathy. To elucidate their significance, the operatively-excised myectomy specimens of 24 patients with hypertrophic-obstructive cardiomyopathy (HOCM), of 18 patients with valvular aortic stenosis and of 10 postmortem normal hearts were investigated. Eight patients with HOCM had dysplastic intramyocardial arteries (greater than 100 microns external diameter) as well as dysplastic arterioles (less than 100 microns external diameter). The value of the scores for the thickness and fibroelastosis of the media was nearly doubled, the tunica intima was frequently thickened, and the lumen was relatively reduced in dysplastic vessels. Neither in controls nor in aortic stenosis dysplastic arteries were found. Volume density of patchy fibrosis (scars) was increased in patients with dysplastic arterial vessels (HOCM II) (7.2 +/- 4.4 Vv%) (p less than or equal to 0.05) as compared with HOCM without dysplastic vessels (HOCM I) (0.8 +/- 2.3 Vv%), with aortic stenosis (0.9 +/- 1.6 Vv%) or with controls (0 Vv%), Patients with HOCM II were significantly (p less than or equal to 0.05) younger (30 +/- 13 years) than those with HOCM I (53 +/- 12 years), aortic stenosis (56 +/- 12 years), or controls (63 +/- 21 years). The anterior septum was significantly thicker in HOCM II (29 +/- 7 mm) than in HOCM I (22 +/- 4 mm), in aortic stenosis (19 +/- 3 mm), or in controls (12 +/- 2 mm). Syncopes were complained by about 75% (6/8) of patients in HOCM II, by 54% (9/16) in HOCM I, and by 44% (8/18) in aortic stenosis (not significant).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

[The growth of coronary artery branches in man under physiological conditions. Morphological studies of corrosion casts of the anterior interventricular branch of the coronary artery].

In corrosion casts of the left anterior descending coronary artery and its branches of higher order, the length, diameter, and number of branches were examined in 20 hearts, from 9 adults, 3 children, 4 new-born and 4 fetuses. We counted 5245 branches in total, thereof 147 branches in the corrosion casts of adult hearts were systematically analyzed, as were 46 branches of children's hearts, 55 branches of the new-born and 35 branches of the fetuses, respectively (left anterior descending coronary arteries and branches of 1st to 6th order). The length of the left coronary arteries and of their branches of 1st and 2nd order increases to almost the same degree as the linear measurements of the hearts. The left anterior descending coronary artery is about four times as long as the 1st order branches and these have twice the length of the 2nd order branches. These differences result from the divergent course of the branches. The results indicate that no significant increase in the number of the 1st to 3rd order branches of the coronary arteries occurs from birth to adulthood in human hearts. During the postnatal growth in human hearts there seems to be no remarkable neogenesis of coronary artery branches of greater diameter. Nearly all of them exist at birth and even in the late fetal period. Their length increases harmonically with the linear measurements of the heart and they become progressively separated. These findings parallel those obtained in a previous study in pigs.

Adolescent↗
PubMed1991

[Arteriosclerotic plaque rupture. Its significance for myocardial infarct, sudden heart death and unstable angina].

In coronary heart disease ruptures of atherosclerotic plaques have a key position. As a rule plaque fissuring develops in the fibrous cap of a complex atherosclerotic plaque with necrotic core. In myocardial infarction in nearly all cases mural or occlusive thrombi develop as a consequence of plaque ruptures. In instable angina, too, plaques with ruptured surfaces are very numerous but often thrombi are smaller than in patients dying from myocardial infarction. Also in cases of sudden death plaque fissurings are frequently observed. Dynamic thrombi covering plaque ruptures may be sources of microemboli in the myocardium.

Angina, Unstable↗
PubMed1990

Well-differentiated papillary mesothelioma of the peritoneum: a borderline mesothelioma. Report of two cases and review of literature.

Well-differentiated papillary mesothelioma (WDPM) is considered to be a distinct subtype of peritoneal mesothelioma. Although the WDPM is usually qualified as benign, the natural history of this lesion has not been clearly established. This report relates to two WDPMs which were found incidentally. In a 51-year-old man the WDPM developed over a period of 5 years into a typically malignant diffuse mesothelioma. Thus, although the WDPM morphologically lacks signs of malignancy, it should be regarded as a borderline mesothelioma.

Ascitic Fluid↗
PubMed1990

Endomyocardial biopsy in infants and children: experience in 60 patients.

In 60 children, aged between 1 month and 22 years (median 3.54 years) and with a body weight of 3-67 kg (median 12.6 kg), transvascular endomyocardial biopsy (EMB) was performed from the right (35 children) or left ventricle (30 children). The specimens were investigated by light and electron microscopy. There were three indications for biopsy: (1) poorly functioning, dilated left ventricle (seven patients with endocardial fibroelastosis, 16 with dilated cardiomyopathy, six from healing/healed or chronic myocarditis); (2) unexplained left ventricular hypertrophy (10 with hypertrophic cardiomyopathy, four with secondary hypertrophy, three with storage diseases); (3) to answer certain questions in eight children (four with hypoxic and two with cytoxic myocardial damage). Retrospectively, there were five nonindicated biopsies. There were no serious complications. Biopsies were diagnostic in 11.7% of cases, helpful in 71.7%, and of no help in 16.6%. Thus even in childhood endomyocardial biopsy is a diagnostic tool which can add useful information on the etiology or pathogenesis of an underlying myocardial disease.

Adolescent↗
PubMed1990

Muscle fiber orientation in the development and regression of right ventricular hypertrophy in pigs.

The development and regression of right ventricular hypertrophy was investigated in 12 pigs with special reference to changes in ventricular function and myocardial fiber orientation. Nine ventricles were pressure-loaded by banding the pulmonary artery for 28-81 days, and four of them were then released from the load by removing the band. Right ventricular systolic pressure (RVSP), end-diastolic pressure (RVEDP) and end-systolic volume index (ESVI) increased significantly during banding and decreased after debanding. End-diastolic volume index (EDVI) and stroke volume index (SVI) showed no significant change during banding and after debanding. The weight of the right ventricle relative to both ventricles (RV/TV) and the thickness of muscle fibers were increased significantly in the loaded ventricles, and reduced again to the control level in ventricles released from the load. The intramyocardial distribution of angles (theta) of inclination of muscle fibers from the transverse plane of the outflow tract was estimated histometrically. There was a significantly larger proporation of circularly oriented fibers (magnitue of theta less than or equal to 30 degrees) in the pressure-loaded ventricles than in the control, whereas these fibers decreased again to the control level after removal of the pressure load. The present findings indicates that 1) the right ventricular hypertrophy induced by pressure loading is characterized not only by an increase in ventricular weight and muscle fiber thickness, but also by a change in intramyocardial fiber orientation, and 2) the hypertrophic right ventricle can regress both functionally and morphologically to a normal state after removal of the pressure load.

Animals↗
PubMed1990

[Capillary length in the human heart during physiological growth and under pathological conditions].

Knowledge about the capillary length in mammalian and human heart is still scanty. Because it is very difficult to examine this parameter directly we used an indirect method. The distance between the arterioles can be used as an approximately measurement for the double capillary length. We tried to measure the distances between arterioles in about 30 postmortem injected hearts using India ink to produce a kind of reflected imitated tabby (tiger) heart pattern. In addition we measured the distances between arterioles with orcein staining in histological preparation of 130 human hearts including 24 hearts with congenital vitia. Our results indicate that from birth there is a determined continuous growth of capillary length with increasing heart weight during physiological development and under pathological conditions. The capillary length in hypertrophic hearts may be an additional functional impairment of the pathological hearts.

Aging↗
PubMed1990

[Quantitative morphologic studies for localizing arteriosclerotic plaques in the circumference of coronary arteries].

In order to determine the distribution of arteriosclerotic plaques in the circumference of coronary arteries 150 hearts were investigated using two different methods. In 100 hearts the coronary vessels were opened longitudinally, and the sites of sclerotic lesions were mapped. The coronary arteries of another 50 hearts were filled with contrast medium, angiography was performed and the arteries were cut into 0.5-cm segments. The first 6 cm of the left anterior descending and the left circumflex arteries and the first 9 cm of the right coronary artery were studied. Segments of 1-cm length in the 100 hearts and of 0.5-cm length in the 50 hearts were examined. It was found, that arteriosclerotic lesions of the coronary arteries are most frequently located on the myocardial side of the vessel circumference. This phenomenon is most evident in the left anterior descending artery, thus possibly being caused by the most pronounced fixation of this artery on the myocardium.

Adult↗
PubMed1989

[Secondary diseases of the heart muscle and their differential diagnosis in childhood].

Possible causes of specific cardiac muscle disease, diagnosis, follow-up and the therapeutic management are discussed on the basis of a series of cases. 8 out of 30 patients who showed the clinical picture of dilative cardiomyopathy (DCM) were found to have a specific cardiac muscle disease. 4 patients had DCM following adriamycin therapy. Fibromuscular dysplasia with renal hypertension, thalassaemia major with secondary haemosiderosis, long-overlooked and untreated athyroidism each caused one case of dilative specific cardiac muscle disease. Once DCM was preceded by the Kawasaki syndrome for over 2 years. Amongst 47 patients with hypertrophic cardiomyopathy there were two children who had undergone ACTH treatment, 6 children born of diabetic mothers, 4 cases of Pompe's disease, and one patient with hypothyroidism resulting in reversible hypertrophy of the cardiac muscle. Different neurodegenerative diseases were associated with cardiac muscle disease in 4 cases, partly dictating the clinical course. Extremely rare was the development over 6 years of cardiac hypertrophy following a burns injury.

Adolescent↗
PubMed1989

Quantitative analysis of fiber disarray developing in papillary muscles unloaded after mitral valve replacement.

Muscle fiber disarray which developed in the papillary muscle released from its chordal attachment after mitral valve replacement (MVR) was analysed histometrically in 23 hearts. The degree of disarray, or how far the fiber arrangement deviated from an ideal condition in which the fibers are considered to be aligned in parallel, was evaluated in terms of the "disarray index". This index corresponds to the ratio of the minor to major axes of a regression ellipse which can be obtained histometrically by plotting the reciprocal of the number of muscle fibers intersected by a test line of equal length in every direction on a polar coordinate system. The index can vary continuously in a range from 0.00 for a completely parallel fiber alignment to 1.00 for a completely random distribution. The estimated index showed a gradual increase from 0.05 to 0.68 according to the postoperative survival period after MVR with a significant positive correlation (r = 0.793, p less than 0.01). The index was inversely correlated with the mean muscle fiber diameter (r = -0.433, p less than 0.05). These results indicate that the disarray which develops in the papillary muscle after MVR is a deformation of the normally parallel arrangement of fibers toward an isotropic texture under focal disruption of the normally longitudinally oriented tensile force.

Adult↗
PubMed1989

[Pathologic anatomy of congenital heart defects].

The heart of neonates and infants with marked hypoplastic left- or right-heart-syndrome contains--despite the very low weight in the hypoplastic parts--myocytes of approximately the same size as in the non-hypoplastic ventricular wall. This means that the number of cells is not constant, because in contrast to the regularly developed right and left ventricular walls, the total number of myocytes in the hypoplastic parts is significantly lower. Hypertrophy of the myocardium in congenital heart disease shows histological and ultrastructural findings that are similar to those found in other forms of myocardial hypertrophy. Hypertrophy is reversible after successful surgical correction. However, regression is often incomplete, especially if surgery is delayed until adolescent or adult life. During this time scar formation in the hypertrophic ventricular wall may develop. In addition to these scars, also postoperative scar formation may contribute to the origin of arrhythmias. In hearts with cyanotic and non-cyanotic vitia distances between capillaries and capillary lengths are approximately the same as in normal hearts. Obviously, these parameters are genetically determined.

Arrhythmias, Cardiac↗