Search PubMed⌕ Search

Biomedical subjects

T Mattfeldt

Publications and source records attributed to T Mattfeldt.

At least 73 records · Page 4Linked to original sources
PubMed1990

The popliteal artery entrapment syndrome: presentation, morphology and surgical treatment of 13 cases.

The morphology, clinical parameters and treatment of the popliteal artery entrapment syndrome (PAES) are presented on the basis of 13 of our own cases and from the literature. PAES is based on a segmental vascular compression due to an anatomical anomaly of the popliteal region and a new classification is presented distinguishing three variants according to the different anatomical conditions. PAES is mostly found in young sportsmen with well-developed muscles. Clinical symptoms are acute or chronic, and the diagnosis is made by physical examination, angiography and Doppler ultrasound, both in neutral position and in plantar flexion. Although thromboendarterectomy in some cases leads to good results, the preferred surgical therapy is decompression of the entrapped artery and reconstruction of the arterial pathway by vein graft interposition. The results were excellent in nine of 13 cases. In two patients, a recurrent thrombosis necessitated a femoro-crural bypass and in two others the entrapment was only diagnosed during reoperation for aneurysms of the venous graft.

Adult↗
PubMed1990

Estimation of surface area and length with the orientator.

The orientator is a new technique for the estimation of length and surface density and other stereological parameters using isotropic sections. It is an unbiased, design-based approach to the quantitative study of anisotropic structures such as muscle, myocardium, bone and cartilage. A simple method for the practical generation of such isotropic planes in biological specimens is described. No special technical equipment is necessary. Knowledge of an axis of anisotropy can be exploited to optimize the efficiency. To randomize directions in space, points are selected with uniform probability in a square using various combinations of simple random, stratified random, and systematic random sampling. The point patterns thus produced are mapped onto the surface of a hemisphere. The mapped points define directions of sectional planes in space. The mapping algorithm ensures that these planes are isotropic, hence unbiased estimates of surface and length density can be obtained via the classical stereological formulae. Various implementations of the orientator are outlined: the prototype version, the orientator-generated ortrip, two systematic versions, and the smooth version. Orientator sections can be generated without difficulty in large specimens; we investigated human skeletal muscle, myocardium, placenta, and gut tissue. Slight practical modifications extend the applicability of the method to smaller organs like rat hearts. At the ultrastructural level, a correction procedure for the loss of anisotropic mitochondrial membranes due to oblique orientation relative to the electron beam is suggested. Other potential applications of the orientator in anisotropic structures include the estimation of individual particle surface area with isotropic nucleators, the determination of the connectivity of branching networks with isotropic disectors, and generation of isotropic sections for second-order stereology (three-dimensional pattern analysis).

Animals↗
PubMed1990

[New methods for the morphometric analysis of anisotropic tissues].

Some unbiased, design-based stereological methods that have recently been developed for the study of anisotropic tissues like muscle, myocardium, brain, cartilage, and skin, are briefly reviewed. Vertical sections permit the unbiased estimation of surface density and mean volume-weighted particle volume from microscopic sections. The available experience includes various studies on malignant melanomas. In addition, the surface area of total organs (e.g., the pleural surface area) can be determined with vertical sections, which was hitherto not feasible. The orientator is a simple method to generate isotropic sections in biological material. With the orientator method it is possible to determine not only the surface density, but also the length density of the objects. Thus the method is suitable for the study of fascicular systems (tubules etc.), and for the study of vascularisation in particular.

Animals↗
PubMed1989

Expression of epidermal growth factor receptor in benign and malignant primary tumours of the breast.

Using the monoclonal antibody EGF-R1, normal mammary gland and a series of 213 unselected primary breast tumours were investigated immunohistochemically for expression of epidermal growth factor receptor (EGFR). In normal breast EGFR was expressed in variable patterns in lobular, ductal, and myoepithelial cells. In fibroadenoma, EGFR was detectable in variable numbers of ductal and myoepithelial cells and in stromal fibroblasts. The myoepithelial compartment of 2 cystosarcomas phyllodes also expressed EGFR. Among the 197 carcinomas tested only 20.3% contained EGFR expressing tumour cells which represented a minority in 12.2%, the majority in 2.1%, and the entire neoplastic population in 6.1% of the cases. Again, non-neoplastic ductal remnants often contained EGFR positive myoepithelial and ductal cells whereas stromal fibroblasts expressed EGFR only occasionally. We conclude that in contrast to the normal state, EGFR-expression is a rather rare phenomenon in breast carcinoma cells, positively correlated with a declining grade of differentiation (p less than 0.025) and at least occasionally associated with squamous metaplasia within the tumour, that EGFR expression is not exclusively restricted to cells of the epithelial lineage, and that EGFR may have other functions not related to proliferation, since it is commonly detectable in myoepithelial cells.

Breast↗
PubMed1989

Reaction patterns of the myocardial interstitium in different models of cardiac hypertrophy--stereological investigations.

Several experimental models of cardiac hypertrophy were investigated in rats: 1. mild hypertrophy induced by physical exercise (18 weeks), 2. mild hypertrophy induced by renovascular hypertension (24 weeks), 3. moderate hypertrophy induced by renovascular hypertension in diabetic and non-diabetic animals (8 weeks), 4. moderate hypertrophy induced by renovascular hypertension in diabetic and non-diabetic animals (12 weeks), 5. moderate hypertrophy induced by thyroxin application (4 weeks), 6. mild hypertrophy in chronic uremia (5/6 nephrectomy, 3 weeks). It is concluded from quantitative stereological parameters of the left ventricular papillary muscles that 1. in hypertrophic hearts myocardial blood flow and oxygen consumption, respectively, rather than the size of muscle fibres determine the capillary supply of the myocardium, 2. interstitial fibrosis occurs in hypertrophy induced by chronic pressure overload and depends on degree and duration of hypertension, 3. the extent of interstitial fibrosis in hypertension is magnified by diabetes mellitus, and 4. the interstitial fibrosis which occurs in chronic uremia is not caused by hypertension.

Animals↗
PubMed1989

Expression of HLA-A, -B, -C, -DR, -DP, -DQ, and of HLA-D-associated invariant chain (Ii) in non-neoplastic mammary epithelium, fibroadenoma, adenoma, and carcinoma of the breast.

Non-neoplastic mammary gland, 20 benign tumors and 206 carcinomas of the breast were immunohistochemically examined for expression of HLA-A, -B, -C, HLA-DR, -DP, and -DQ molecules and the HLA-D associated invariant chain (Ii). In contrast to cells from benign lesions, tumor cells of 51.2% of carcinomas had an abnormally low content of HLA-A, -B, and -C determinants ranging from reduction of antigenic density per cell (28.8%) over an incomplete (15.6%) to complete loss of antigens (6.8%). Associated with lymphohistiocytic stromal infiltrates, HLA-D/Ii determinants were found to be induced in benign duct and acinar epithelium after the order Ii greater than or equal to HLA-DR greater than or equal to HLA-DP greater than or equal to HLA-DQ. These antigens were also expressed, mostly noncoordinately, in 55.5% of carcinomas, and in 98 cases according to the above order. In 28.6%, Ii expression clearly exceeded HLA-D antigen expression; conversely, 6.2% contained HLA-DR+/Ii- tumor cell subsets. In breast carcinoma, the association of reduced HLA-A, -B, and -C expression and a noninduction of HLA-DR was highly significant (P less than 0.0009), suggesting an abnormal signal acting down-regulating on the expression of both classes of antigens. Because the modality of HLA-A, -B, and -C and HLA-D/Ii expression correlated with neither tumor type nor grade, it might be an independent parameter.

Adenofibroma↗
PubMed1989

[The radiologic diagnosis of inflammatory aneurysms].

An inflammatory aneurysm is defined as a nonbacterial special type of atherosclerotic aneurysm. The macroscopic characteristics are: a porcelaneous appearance, excessive thickening of the aortic wall, and perianeurysmal adhesions. Chronic inflammatory infiltrations, which are localized in the adventitia, can be found via microscopy. Six of forty-three patients with abdominal aortic aneurysms were found to have an inflammatory aneurysm at operation. In a retrospective study, we examined the sonographic, computed tomographic and angiographic appearance of inflammatory aneurysms. Only with computed tomography can thickening of the aneurysmal wall be demonstrated; angiography does not have this capacity and can only find an inflammatory aneurysm in particular cases.

Angiography, Digital Subtraction↗
PubMed1987

Volume estimation of biological objects by systematic sections.

The absolute volume of biological objects is often estimated stereologically from an exhaustive set of systematic sections. The usual volume estimator V is the sum of the section contents times the distance between sections. For systematic sectioning with a random start, it has been recently shown that V is unbiased when m, the ratio between projected object length and section distance, is an integer number (Cruz-Orive 1985). As this quantity is no integer in the real world, we have explored the properties of V in the general and realistic situation m epsilon R. The unbiasedness of V under appropriate sampling conditions is demonstrated for the arbitrary compact set in 3 dimensions by a rigorous proof. Exploration of further properties of V for the general triaxial ellipsoid leads to a new class of non-elementary real functions with common formal structure which we denote as np-functions. The relative mean square error (CE2) of V in ellipsoids is an oscillating differentiable np-function, which reduces to the known result CE2 = 1/(5m4) for integer m. As a biological example the absolute volumes of 10 left cardiac ventricles and their internal cavities were estimated from systematic sections. Monte Carlo simulation of replicated systematic sectioning is shown to be improved by using m epsilon R instead of m epsilon N. In agreement with the geometric model of ellipsoids with some added shape irregularities, mean empirical CE was proportional to m-1.36 and m-1.73 in the cardiac ventricle and its cavity. The considerable variance reduction by systematic sectioning is shown to be a geometric realization of the principle of antithetic variates.

Animals↗
PubMed1987

Stereology and flow-cytometry of well-differentiated follicular neoplasms of the thyroid gland.

A retrospective analysis of surgically resected thyroid nodules by stereology and DNA flow cytometry was performed in 15 follicular adenomas and 15 well-differentiated follicular carcinomas. The criteria for diagnosis were based on the WHO classification of thyroid tumours. By area-weighted random sampling of the visual fields for light-microscopic stereology, any subjective selection bias was precluded, and each point within the embedded neoplastic tissue was given equal probability of being analyzed. 150-250 tumour cell nucleus (TCN) profiles were studied per case by a semiautomatic image analyzing system. Flow cytometric analyses included measurement of the DNA-index, and the percentages of cells in S-phase and in G2/M-phase. Adenomas and carcinomas did not differ in stereological estimates related to TCN size. As examination of the stereological techniques by nested analysis of variance showed that this result cannot be ascribed to inaccurate methods, it follows that determination of TCN size is not a useful tool for the diagnosis of malignancy in well-differentiated thyroid tumours. Both groups included similar proportions of diploid and aneuploid neoplasms. In the carcinoma group the percentage of tumour cells in the G2/M-phase was more than twice as high than in the adenoma group (P less than 0.01). The ratio of short to long TCN profile axis was significantly smaller, and the coefficient of variation of TCN profile area was significantly higher in carcinomas than in adenomas. These findings are consistent with more unequiaxed TCN and higher anisokaryosis in the malignant tumours. Despite the significant differences, however, overlap of data from individual cases precludes the use of these estimates as diagnostic criteria. Pooling of the follicular tumours and dichotomizing the sample by the DNA-index showed that mean TCN profile area is increased and surface-to-volume ratio of TCN is decreased in aneuploid as compared to diploid tumours. This finding indicates that aneuploidy is associated with an increase of TCN size.

Adenocarcinoma↗
PubMed1987

Synergistic effects of diabetes mellitus and renovascular hypertension on the rat heart--stereological investigations on papillary muscles.

The effects of combined renovascular hypertension and diabetes mellitus on the rat heart were investigated in order to detect possible synergistic effects of the two conditions. Hypertensive diabetic and hypertensive nondiabetic young male Wistar rats were compared with diabetic and non-diabetic controls. Since the normal body weight increase of the diabetic animals was markedly suppressed a weight-matched nondiabetic control group was introduced in addition. Hypertension was established for eight weeks by a surgical stenosis of the left renal artery, diabetes mellitus was maintained for four weeks after a single intraperitoneal injection of 75 mg/kg streptozotocin. Light and electron microscopic stereological parameters were obtained for the left ventricular papillary muscles. The whole hearts were also investigated histologically. Qualitative morphology failed to substantiate synergistic effects in the hypertensive diabetic rats. Vascular abnormalities were not observed. The stereological parameters, however, revealed microstructural reactions which were observed exclusively in the hypertensive diabetic group: the volume ratio of mitochondria-to-myofibrils was decreased, the surface-to-volume ratio of mitochondria was increased (reduction of mitochondrial size) and the mean cross sectional area of capillaries was decreased. Similar quantitative mitochondrial changes have been frequently described in long-standing hypertension, but in the present investigation, they were not found in the nondiabetic hypertensive group. It is therefore concluded that diabetes mellitus potentiates the effects of chronic pressure overload on myocardial cells. However, the myocardial fibrosis which has been found by other groups at later stages of hypertension and/or diabetes mellitus was not detected in the present study. The reduced mean cross sectional area of capillaries in hypertensive-diabetic rats may be correlated with early molecular changes of the myocardial interstitium or with early abnormalities of small arteries. Thus our stereological results support the hypothesis that a non-coronary hypertensive diabetic cardiomyopathy occurs in mammalian hearts.

Animals↗
PubMed1987

Growth of capillaries and myocardial cells in the normal rat heart.

The normal growth process of myocardial cells and capillaries in the late postnatal period (after weaning) was studied in 33 normal male Wistar rats (group I: 5 weeks, n = 9; group II: 7 weeks, n = 7; group III: 13 weeks, n = 8; group IV: 52 weeks, n = 9). The rats were fixed by retrograde vascular perfusion via the abdominal aorta. Two transverse and 2 longitudinal sections per animal were selected at random from the left ventricular papillary muscles for light and electron microscopic stereological investigation. Length density and surface density of myocardial cells and capillaries were estimated with correction for partial anisotropy and curvature by means of the mathematical model of a Dimroth-Watson orientation distribution. The results were analyzed by allometric techniques. Relative left and right ventricular weight decreased continuously throughout the growth process; in terms of allometry, ventricular weight was proportional to (body weight). The capillaries showed predominantly longitudinal growth with nearly constant cross-sectional area, whereas the myocardial cells grew by nearly harmonic enlargement into all three directions of space. The relation between total capillary length and left ventricular weight could be described in close approximation by the allometric model (r = 0.98, P less than 0.001). Corresponding to the result that total capillary length was proportional to (left ventricular weight)0.71, the myocardial capillarization (length, surface area, and volume of capillaries per unit tissue volume) decreased with increasing heart size. As allometry makes possible the quantitation of the intensity of growth processes by a single dimensionless number (the allometric exponent), this method permits a convenient interlaboratory comparison of growth studies, and it allows a comparison of capillary reactions during maturation and in experimental cardiac hypertrophy.

Animals↗
PubMed1987

Dipyridamole-induced neoformation of capillaries in the rat heart. Quantitative stereological study on papillary muscles.

Eighteen young male Wistar rats were randomly divided into two groups of equal size. Each experimental animal was treated with the powerful vasodilating drug dipyridamole (4 mg kg-1 intraperitoneally twice daily) for a period of 6 weeks. The control animals received sham injections with saline. The rats were fixed by retrograde vascular perfusion. Seven transverse and two longitudinal sections per animal were randomly selected from the left ventricular papillary muscles for stereological investigation. Length density of capillaries (length of capillaries per unit of tissue volume), surface density of capillaries (surface area of capillaries per unit of tissue volume) and the "true" three-dimensional capillary-fiber ratio (length of capillaries per unit length of myocardial fibers) were estimated by means of the Dimroth-Watson distribution, a mathematical model of directional statistics which assumes that the capillary directions scatter around the longitudinal axis of the muscle. This model was recently introduced into the stereology of myocardial capillaries and leads to a more accurate quantitation of the capillary network than parameters used hitherto, such as the "capillary density" (number of capillary profiles per mm2 of cross sectional area) and the "capillary-fiber ratio" (number of capillary profiles per number of myofiber profiles in cross sections). After chronic dipyridamole treatment, the length density of myocardial capillaries (+5%; p less than 0.02), the surface density of capillaries (+8%, p less than 0.01) and the three-dimensional capillary-fiber ratio (+6%, p less than 0.05) were increased. It is therefore concluded that the vasodilating drug dipyridamole evokes capillary growth in the heart which may be induced by mechanical factors via the enhanced myocardial blood flow. Investigation of the frequency distribution of capillary directions in space in both groups provided evidence that the capillary growth resulted from neoformation of capillaries.

Animals↗
PubMed1987

Statistical methods for growth allometric studies.

Simple least square regression analysis, major axis regression, and reduced major axis regression have been advocated for straight line fitting to the logarithmically transformed data pairs in bivariate allometric studies. As all these techniques are based on rigid a priori assumptions on the error structure, their application may lead to considerable biases in slope estimation if these requirements are not met. A different mathematical model, the linear functional relationship, allows to remove the bias by estimating the error structure from grouped empirical data. The model is applicable to interspecific and cross-sectional growth allometric studies where natural grouping criteria are available (species, age). The technique is illustrated by growth allometry of myocardial cells and capillaries in the late postnatal period (after weaning) in 33 normal male Wistar rats (group 1: 5 weeks, group 2: 7 weeks, group 3: 13 weeks, group 4: 52 weeks). In left ventricular myocardium fixed by vascular perfusion, length and volume densities of myocardial cells and capillaries were estimated by stereological techniques at the light and electron microscopic level. Total capillary length and total myocardial cell volume were scaled to total myocardial cell length. A comparison of the scaling methods showed an underestimation of the slope and its confidence interval by all regression techniques, which would have led to the erroneous conclusion that the myocardial cell does not remain geometrically similar throughout the normal growth process. Linear functional relationship and the technique of instrumental variables led to nearly identical results and were both compatible with geometric similarity of the myocardial cell during growth. Positive allometry of total capillary length to total myocardial cell length (b = 1.674) demonstrates continuous neoformation of capillaries. The intensity of capillary proliferative activity during growth was intermediate between the reactions observed in myocardial hypertrophy due to pressure overload and that due to physical training. This agrees with the fact that both systemic arterial pressure and cardiac output increase during maturation. The study is designed as a worked example which should enable the practicing researcher to treat data from cross-sectional growth allometric studies with a simple and unbiased statistical method.

Animals↗
PubMed1986

[Isolated spontaneous coronary artery dissection. A report on the differential diagnosis of coronary heart disease].

A complete review of the literature on the disease entity isolated spontaneous coronary artery dissection (72 ascertained cases with our own three) is given. The emphasis is placed on differential diagnosis of coronary heart disease, particularly in young patients without typical atherosclerotic risk factors. Isolated spontaneous coronary artery dissection is defined as a spontaneously dissecting hematoma limited to one or more coronary arteries. Women are involved considerably more frequently than men (84% of cases). Mean age at onset of the disease is 41 years (range: 21-70 years). The main site of involvement is the left coronary artery (79% of cases). In one-third of the female patients there is a temporal relationship to pregnancy (peripartum coronary artery dissection). Three types can be differentiated by coronary arteriography. Less than one-third of the patients survive the first 24 h after acute onset of symptoms; attempts at emergency reperfusion of the ischemic myocardium by aortocoronary bypass surgery or thrombolytic therapy have not been successful.

Adult↗
PubMed1986

Morphological reaction patterns in experimental cardiac hypertrophy--a quantitative stereological study.

Four experimental models of myocardial hypertrophy were investigated in rats: 1. Mild hypertrophy induced by physical exercise, 2. mild hypertrophy induced by chronic pressure overload (24 weeks), 3. moderate hypertrophy induced by chronic pressure overload (8 weeks), 4. moderate hypertrophy in diabetes induced by chronic pressure overload (8 weeks). Stereological investigations on left ventricular papillary muscles disclosed different morphological reaction patterns: 1. The capillary bed of the myocardium responded differently in mild hypertrophy:physical training, but not mild chronic pressure overload, evoked neoformation of capillaries. 2. Mild hypertrophy and moderate hypertrophy induced by chronic pressure overload were not associated with quantitative structural reactions of myofibrils and mitochondria. Those alterations appeared, however, in hypertensive-diabetic rats with moderate hypertrophy. Our data provide further experimental evidence for the existence of a hypertensive-diabetic cardiomyopathy.

Animals↗