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Biomedical subjects

G Schuler

Publications and source records attributed to G Schuler.

At least 343 records · Page 19Linked to original sources
PubMed1982

The effect of aortic valve replacement on survival.

We retrospectively studied 252 operated and 47 unoperated patients with isolated aortic valve disease. Aortic valve replacement (AVR) was recommended to all patients based on clinical and hemodynamic data. Preoperative hemodynamic and angiographic data were similar in operated and unoperated cohorts. Seventy-one percent of patients received a Björk-Shiley prosthesis. Operative mortality was 7% for the entire surgical series. For patients with predominant aortic stenosis (AS), survival at 3 years was 87% in operated and 21% in unoperated patients (p less than 0.001). For patients with predominant aortic insufficiency (AI), the 5-year survival rate was 86% in operated and 87% in unoperated patients (NS). AVR improved long-term survival in patients with AS who had normal or impaired left ventricular (LV) function. In patients with AI and normal LV function, survival was not improved after AVR, but those with LV dysfunction who were operated on tended to survive longer (NS). Long-term survival of unoperated patients with AI was better than that in unoperated patients with AS. We conclude that AVR improves long-term survival in patients with AS who were normal or abnormal LV function, and that AVR does not change long-term survival in patients with AI, although those with LV dysfunction tended to survive longer.

Adult↗
PubMed1982

[Epidermolysis bullosa acquisita: diagnosis by optic immunofluorescent demonstration of junctional antigens and vitamin E treatment].

In a patient with epidermolysis bullosa acquisita the characteristic dermolytic cleavage was demonstrated by electron microscopy and by mapping of antigenic determinants (type IV collagen, laminin, bullous pemphigoid antigen) of the dermal-epidermal junction. The latter method represents a rapid and reliable way to determine the cleavage plane in diseases which display subepidermal blister formation at the light-microscopic level. The classification of epidermolysis bullosa acquisita is still under dispute. Due to its highly characteristic clinical, ultrastructural, and immunologic features and pending further experimental data, epidermolysis bullosa acquisita should be regarded as a separate disease entity; its lumping together with cicatricial pemphigoid, as proposed by some authors appears speculative. Therapy of epidermolysis bullosa acquisita is generally regarded as difficult; following a 3-year course of high dose vitamin E therapy our patient underwent complete clearing; the possibility of a spontaneous remission, on the other hand, cannot be unequivocally ruled out.

Adult↗
PubMed1982

[Multiple atypical milker's nodes in scalded areas].

This case report describes the occurrence of multiple atypical milker's nodules in scalded skin. This hitherto unknown manifestation of paravaccinia virus infection is transmitted indirectly by virus contaminated water.

Burns↗
PubMed1982

[Bone marrow culture, cytochemistry and electron microscopy in agar in patients with preleukemic syndrome and aplastic anemia].

Thirty-seven patients with chronic cytopenia were studied using a CFU-c assay in agar. On the basis of the growth pattern three types of preleukaemic syndrome (PL) and two types of aplastic anaemia were distinguished. Further evaluation of the bone marrow dysfunction was attempted with a combined application of cytochemistry and electron microscopy for the morphologic study of cells proliferating in vitro. Well-defined maturation defects in the growing cells from the bone marrow of patients with PL were demonstrated with cytochemical stainings performed in agar. These results were supported by electron microscopic findings of Auer-body-like inclusions in "statu nascendi" in the vacuoles of preleukaemic cells. On the basis of our results a high risk group of PL for development of overt leukaemia and a group of patients with a grave prognosis in aplastic anaemia were distinguished. The data obtained are relevant for the clinical diagnosis and prognosis of patients with cytopenias.

Adult↗
PubMed1982

Differential lectin binding to mammalian keratinocytes and melanocytes in vitro.

Guinea pig melanocytes and keratinocytes in primary mixed epidermal cell cultures were investigated as to their differential lectin binding capacities. Cultures were exposed to a battery of fluorescent (FITC and TRITC) lectins and lectin derivatives for ultrastructural visualization (HRP-labeled lectins for a one-step technique and biotinylated lectins followed by avidin-HRP in a two-step technique). Most of the lectins bound to both melanocytes and keratinocytes. Lectins with specificity for N-acetyl-galactosamine and terminal D-galactose bound only to keratinocytes; melanocytes were reactive, though, at contact sites of dendrites with keratinocyte cell bodies. Ulex europaeus (specific for L-fucose) bound to neither melanocytes no keratinocytes. Neuraminidase pretreatment restored the capacity of melanocytes to bind all lectins except Ulex europeaus. It is concluded that the melanocytes receptor sites for N-acetyl-galactosamine and terminal D-galactose are masked by sialic acid residues; they appear to emerge, though, under conditions of cell-to-cell contact as in the course of pigment transfer. Masking and demasking processes may therefore bear a functional significance.

Acetylgalactosamine↗
PubMed1981

[Angina pectoris syndrome in patients with normal coronary arteriograms (X syndrome) (author's transl)].

In 37 patients with typical exercise-dependent angina pectoris but with normal coronary arteriograms and normal left ventricular function at rest (X syndrome), the dipyridamole-induced dilatory reserve of the coronary vascular system was reduced significantly to about 50% of control values (P less than 0.001). There were no changes in the small vessels causing the reduced dilatory reserve, but ultrastructural changes in the mitochondria were demonstrable. In the patients with X syndrome there was a significant reduction of lactate extraction (P less than 0.05) after electrical atrial stimulation (150/min) and in most cases lactate production was demonstrable. In the control group the myocardial lactate uptake was unchanged. Left ventricular function in patients with X syndrome was normal at rest whereas during exercise it was significantly reduced (P less than 0.001). These results show that X syndrome consists of a particular form of ischaemic heart disease with still normal left ventricular function at rest, but disordered pump activity during physical stress.

Adult↗
PubMed1981

Reliability of echocardiographic and electrocardiographic parameters in assessing serial changes in left ventricular mass.

A reliable noninvasive index of left ventricular mass would be useful in following patients with valvular heart disease and left ventricular hypertrophy. We reviewed concurrent electrocardiograms and echocardiograms from 54 subjects, 39 patients with aortic or mitral valve disease and 15 normal subjects. Pre- and early postoperative echocardiographic estimates of left ventricular mass in 17 patients who had valve replacements correlated well (r = 0.96, p less than 0.001) and demonstrated little change in mean values despite altered left ventricular dimensions. Echocardiographic estimates of left ventricular mass were, therefore, used as a standard for evaluating other noninvasive indices. Precordial electrocardiographic voltage showed a weak correlation with left ventricular mass in the study group as a whole (r = 0.59, p less than 0.001), but no correlation in patients with volume overload (r = 0.36, p = NS). In 18 patients who had preoperative and three separate postoperative studies at least eight weeks apart, changes in left ventricular cross-sectional area (an index of left ventricular mass which corrects for changes in left ventricular volume) closely followed alterations in left ventricular mass. However, changes in posterior wall and interventricular septal thickness often resulted from altered ventricular volume and did not accurately reflect directional changes in left ventricular mass. Serial changes in electrocardiographic voltage were similarly unreliable. We conclude that left ventricular mass and cross-sectional area by echocardiography allow accurate noninvasive assessment of left ventricular mass, whereas wall thickness and electrocardiographic changes do not.

Cardiomegaly↗
PubMed1981

A micro-culture system for cloning human T lymphocytes in agar.

A simple and reproducible single-layer micro-agar culture system for cloning of human T lymphocytes has been described. The system consists of an agar layer, in which mononuclear cells from peripheral blood were suspended, and a liquid overlayer containing the mitogenic substance. The advantages of the described method are a low incubation volume (0.5 ml) and the liquid overlayer. The addition of different test substances to the liquid overlayer is simple and easily controllable. Depending on the agar concentration a different number of formed colonies can be found floating in the liquid phase. The morphological, cytochemical and immunological characteristics of the cells from those aggregates could be easily studied. The T-cell characteristics of formed clusters and colonies was confirmed by immunofluorescence and E rosette formation. The effects of agar, serum and cell concentrations, as well as the mitogenic activation caused by three lectins on the development and number of colonies were studied on day 7, 10 and 14 of incubation.

Clone Cells↗
PubMed1981

Differences of cell surface label distribution and redistribution patterns between mammalian keratinocytes and melanocytes in culture.

Primary guinea pig epidermal cell cultures were subjected to a variety of ultrastructural surface labeling techniques specific for lectin binding sites (Concanavalin A-horseradish peroxidase, wheatgerm agglutinin-chitobiosyl-horseradish peroxidase) or anionic surface sites (Ruthenium red, cationized ferritin). All these techniques were carried out on fixed cells; with cationized ferritin, labeling was also performed on unfixed, viable cells by incubation at 4 degrees C and 37 degrees C for various time periods. Lectin labeling resulted in a diffuse pattern identical for both melanocytes and keratinocytes. Different patterns were obtained with the markers for anionic sites: with both ruthenium red and cationized ferritin, fixed keratinocytes were more heavily labeled than melanocytes, the label being diffuse with randomly distributed globular condensations. Melanocytes, in contrast, were lined by a thin uniform band-like label. On viable keratinocytes, exposed to cationized ferritin at 4 degrees C, the label was confined to randomly disseminated patches which most probably represent the "inherent" distribution of anionic surface sites. At 37 degrees C, this pattern was progressively changed by cluster formation as expression of ligand induced label redistribution, shedding and endocytosis of label material. In contrast, viable melanocytes lacked all of these activities except endocytosis, invariably displaying the same uniform diffuse labeling pattern as fixed melanocytes. It is concluded that melanocytes differ from keratinocytes with regard to quantity, distribution, and lateral mobility of anionic surface sites whereas no differences pertain to quantity and distribution of the binding sites to the lectins tested.

Animals↗
PubMed1981

Immunofluorescence mapping of antigenic determinants within the dermal-epidermal junction in the mechanobullous diseases.

The classification of mechanobullous diseases often depends on the electron microscopic distinction of intradermal (dermolytic), junctional and intraepidermal sites of cleavage. Electron microscopy is tedious and time consuming. In this report we describe a different approach to the determination of the cleavage plane by using a method which recognizes subtle differences in the localization of antigenic structures relative to the cleavage plane. Cryostat sections of lesional and extralesional skin of 3 patients with dermolytic epidermolysis bullosa, 3 with epidermolytic epidermolysis bullosa and 8 with junctional epidermolysis bullosa were examined by immunofluorescence, with specific antisera against type IV collagen (localized within the basal lamina); against laminin (noncollagenous protein, localized in the lamina lucida); and with bullous pemphigoid antibodies (directed against the bullous pemphigoid antigen localized in the lamina lucida). All specimens were also examined by electron microscopy. In dermolytic epidermolysis bullosa (where cleft formation occurs intradermally) type IV collagen, laminin and the bullous pemphigoid antigen were consistently found in the roof of the blister, whereas in junctional epidermolysis bullosa (where the cleft occurs in the lamina lucida) type IV collagen and laminin were found on the floor of the blister whereas bullous pemphigoid antigen was present mainly on the roof, but focally also on the floor, of the blister. In epidermolytic epidermolysis bullosa (where the cleft is intraepidermal) all antigens were localized below the cleavage plane. In all cases electron microscopy confirmed the level of cleft formation predicted from the immunofluorescence mapping of the antigenic sites. The described method equals electron microscopy in accuracy but it is more rapid and simpler to perform.

Collagen↗
PubMed1981

Ultraviolet light depletes surface markers of Langerhans cells.

This report defines the influence of ultraviolet light (UV) on Langerhans cells (LC). Human volunteers and hairless mice (Swiss ha/ha) were exposed to various single and/or cumulative doses of either UV-A, UV-B, or UV-A plus small amounts of UV-B (UV-A (+B)). 24 hr after the last irradiation, morphology of the entire epidermis was evaluated by both light and electron microscopy while LC, in addition, were tested for expression of specific histochemical (ATPase) and functional immunological markers (Ia antigens). In both men and mice, cumulative doses of either 80-120 J/cm2 UV-A (+B) or 1-2 X 100 J/cm2 UV-A resulted in a dramatic reduction of cells exhibiting ATPase and Ia-reactivity. In the UV-B spectrum, single doses of 60-80 mJ/cm2 produced a virtually complete elimination of LC membrane markers. By contrast, pemphigus antigens of keratinocytes were unaffected by these energy doses. Electron microscopy revealed cellular damage of some LC after UV-doses which produce a virtually complete abolition of LC membrane markers. At certain dose ranges (15-30 mJ/cm2 UV-B and 1 x 40 to 2 x 100 J/cm2 UV-A) LC were the only epidermal cells to display morphological damage at the ultrastructural level whereas higher doses affected all epidermal cells. The finding that LC surface markers and to a lesser extent the cells themselves are particularly susceptible to UV irradiation has important implications in view of previous findings that LC are potent stimulators of antigen-specific and allogeneic T cell activation. UV-induced alteration of LC plasma membrane integrity may represent a tool to manipulate adverse immune reactions involving the epidermis.

Adenosine Triphosphatases↗
PubMed1981

The linearity of the end-systolic pressure-volume relationship in man and its sensitivity for assessment of left ventricular function.

The linearity and sensitivity of the end-systolic pressure-volume (P-Ves) relation to the inotropic state of the left ventricle were investigated in 11 patients with coronary heart disease and one patient with congestive cardiomyopathy. To minimize autonomic reflex responses, propranolol, 0.15 mg/kg, and atropine, 1 mg, were administered i.v. at the beginning of the study. Three ventriculograms were performed: at rest, after oral isosorbide dinitrate, 10 mg (systolic pressure decrease greater than or equal to 15 mm Hg), and during infusion of methoxamine, 2 mg/min (systolic pressure increase greater than or equal to 10 mm Hg). The three points of the Pv-Ves relation showed linearity (r greater than or equal to 0.96). The relation between the slope k of the P-Ves relation and the left ventricular ejection fraction at rest was best described by an exponential function (r = 0.94). The use of peak systolic pressure instead of end-systolic pressure showed equally good results. The intercept of the P-Ves line on the abscissa, which represents the theoretical end-systolic volume at zero pressure, was not related to the ejection fraction under control conditions. The P-Ves relation in postextrasystolic beats was displaced toward the left (smaller end-systolic volumes) and became steeper.

Atropine↗
PubMed1981

[The effect of tricuspid insufficiency on right ventricular performance in patients with valvular heart disease (author's transl)].

The hemodynamic effect of tricuspid insufficiency on right ventricular function was studied in 25 patients with rheumatic heart valve disease. 10 patients had mixed valve disease without tricuspid insufficiency (group A), and 15 patients had mixed mitral valve disease with tricuspid insufficiency (group B). Mitral valve area (1.76 vs. 1.66 cm2) and mitral regurgitant fraction (55 vs. 45%) were not significantly (p greater than 0.05) different between groups. Patients of group B revealed higher right atrial and right ventricular end-diastolic pressures than patients of group A. Right ventricular ejection fraction was lower in group B as compared to group A (44 vs. 52%, p less than 0.05). During ergometric exercise right atrial pressure was higher in group B as compared to group A (19 vs. 14 mm Hg, p less than 0.05), but mean pulmonary artery pressure (48 vs. 51 mm Hg, p greater than 0.05), cardiac index (3.3 vs. 3.31/min . mi2, p greater than 0.05) and stroke index (27 vs. 25 ml/m2, p greater than 0.05) were not significantly different. In mixed mitral valve disease associated with tricuspid regurgitation, right ventricular function is impaired when compared to mixed mitral valve disease of equal severity but without tricuspid regurgitation. Exercise induces a further augmentation of right atrial pressure in these patients with tricuspid regurgitation. We conclude, right atrial pressure elevation is not only the consequence of tricuspid regurgitation in group B but also the consequence of impaired right ventricular function. Impairment of right ventricular function is further augmented during exercise.

Adult↗
PubMed1981

[Effect of intracoronary fibrinolysis on left ventricular diastolic function in patients with acute myocardial infarction (author's transl)].

In 22 patients with acute myocardial infarction, intracoronary infusion of streptokinase was begun 3.2 +/- 1.4 hours after the onset of symptoms. In 71% of patients recanalization of a completely occluded artery could be achieved. In 12 successfully treated patients left ventricular hemodynamics (left ventricular diastolic compliance and regional wall motion) were compared before and 4 weeks after recanalization. 4 weeks after intracoronary fibrinolysis left ventricular end-diastolic pressure had fallen (from 20 to 15 mm Hg, p less than 0.05), diastolic compliance had improved (p less than 0.05) and infarct size was reduced (p less than 0.05) compared to the acute stage of myocardial infarction. Left ventricular hemodynamics of 16 patients without heart disease (group A) and 22 patients with chronic myocardial infarction treated medically (group B) were compared to the findings of patients with acute myocardial infarction (group C). Group B and C showed reduced diastolic compliance as compared to group A (p less than 0.001). When group B and c were compared with identical size of akinesis (as measured by the number of asynergic hemiaxes), there was no significant difference of diastolic compliance. Reduction of diastolic compliance correlated linearly with infarct size (r = 0.73, r = 0.78). The results indicate that successful early reperfusion of acute myocardial infarction leads to a reduction of infarct size.

Adult↗
PubMed1980

Expression of basement membrane zone antigens at the dermo-epibolic junction in organ cultures of human skin.

Using the epithelial outgrowth in organ cultures of human skin ("epiboly") as a model system for basement membrane zone neogenesis, the emergence of various antigenic determinants of the junction zone (bullous pemphigoid antigen, type IV collagen and laminin) was studied and the time sequence of their appearance assessed. All 3 antigens were found at the newly built dermo-epibolic junction; their synthesis, however, followed a distinct time sequence: bullous pemphigoid antigens emerged synchronously with the advancing tip of the migrating epithelium, whereas type IV collagen and to a greater extent, laminin, appeared with considerable delay. At the ultrastructural level, the formation of basal lamina accompanied the emergence of type IV collagen and laminin.

Antigen-Antibody Reactions↗
PubMed1980

Diffuse melanosis in metastatic melanoma. Further evidence for disseminated single cell metastases in the skin.

Electron microscopy (EM) and electron microscopic cytochemistry have shown that diffuse melanosis in advanced metastatic melanoma is the result of an unlimited spread of single melanoma cells throughout the dermis; these cells retain their melanogenic capacity and continue to produce melanized melanosomes which eventually are deposited within dermal macrophages and thus impart to the skin a diffuse slate-blue color. These findings are in accordance with previous observations in a similar patient and thus support the concept that single cell metastasis represents a common pathogenic event in these patients.

Adult↗