Biomedical subjects

H J Wagner

Publications and source records attributed to H J Wagner.

At least 19 recordsLinked to original sources

PubMed1998

[Infrapopliteal angioplasty: a forgotten region?].

Although percutaneous transluminal angioplasty (PTA) has become established as an endovascular technique--in the more strict sense as a balloon dilatation but being increasingly supplemented by stent implantations--for many vascular regions, reports on infrapopliteal angioplasties are rather scarce. With the development of hydrophilically coated guide wires, improved catheter materials, and dedicated balloon catheters for infrapopliteal use, dilatation treatments distal of the popliteal artery are now standard procedures. Major advances in peri-interventional drug management have also made their contribution. The initial technical and clinical results obtained are excellent. For the majority of the patients, the main concern is for limb salvage. In this context, infrapopliteal PTA also achieves satisfactory results. However, the long-term results must still be considered as unsatisfactory since recurrences are frequent and require repeat interventions. Therefore new therapeutic strategies are required that can reduce re-stenoses especially in this peripheral vascular segment.

Angioplasty, Balloon↗

PubMed1997

Connectivity patterns of cone horizontal cells in blue acara (Aequidens pulcher, Cichlidae) reared in different light regimes.

Two types of cone horizontal cells were identified morphologically in the retina of a trichromatic fish by fluorescent labelling with Lucifer Yellow and confocal laser scanning microscopy. H1 cells are located adjacent to the outer plexiform layer, have large somata, small dendritic fields, and contact all cone types. H2 cells are positioned vitread to the H1 cells, have small somata, and large dendritic fields. Their dendrites invaginate the synaptic pedicles of short wavelength sensitive single cones and show a significant preference for one of the spectrally different members of the double cones, presumably the middle wavelength sensitive member. We tested the impacts of different visual environments on the development of these connectivity patterns and found minor changes induced by rearing in white light of different intensities or monochromatic blue light.

Adaptation, Physiological↗

PubMed1997

[Combined intraoperative retrograde stent implantation and thrombendarterectomy of the carotid artery].

HISTORY AND CLINICAL FINDINGS: A 63-year-old man developed recurrent transitory ischaemic episodes of vertigo and weakness in the legs 6 weeks before admission. 3 weeks later he had a left amaurosis fugax. A stenotic murmur was heard over the left carotid artery. INVESTIGATION: Intraarterial digital subtraction angiography of the arteries to the head revealed occlusion of the right internal carotid artery (RICA) and marked narrowing at the origin of the left common carotid artery (LCCA), which could not be passed by catheter. TREATMENT AND COURSE: As a catheter could not be passed into the LCCA, a stent was at operation placed retrogradely into it. Intraoperative angiography showed subtotal stenosis of the left ICA, which was treated by thrombendarterectomy and dacron patch-plasty. The postoperative course was without complication and the patient was free of symptoms. Follow-up angiography was unremarkable. CONCLUSION: If a stenosis of the carotid artery cannot be passed by catheter, intraoperative retrograde placement of a stent is an alternative to percutaneous antegrade transluminal angioplasty or surgical bypass.

Carotid Artery, Internal↗

PubMed1997

Density ratio of dopaminergic versus serotonergic cells correlates with cone-to-rod ratio in teleost retinas.

Dopaminergic and serotonergic cells were visualised immunohistochemically with antibodies against tyrosine hydroxylase and serotonin in retinal wholemounts of eight teleosts from different habitats and with different rod-to-cone ratios. The cell densities were calculated, and the density ratio of dopaminergic cells versus serotonergic cells was compared among these fish species. The density ratio was high (1.9-2.7) in three out of the four species of cichlid fish studied with cone densities roughly equalling rod densities, medium in roach (0.8) where rods dominate cone numbers, and low in deep-sea fish (0.2-0.4) with pure rod retinas. These observations confirm earlier findings on the species-specificity of the ratio of dopaminergic versus serotonergic cells in the retina and further demonstrate a close correlation between the rod-to-cone ratio, and the density ratio of dopaminergic versus serotonergic cells in the inner retina. The possible significance for the processing of photopic and scotopic information in the inner retina is discussed.

Animals↗

PubMed1997

Lytic replication of Epstein-Barr virus in the peripheral blood: analysis of viral gene expression in B lymphocytes during infectious mononucleosis and in the normal carrier state.

Epstein-Barr virus (EBV) has been shown to establish latency in resting B lymphocytes of the peripheral blood. This creates a virus reservoir in contrast to lytic virus replication, which is thought to be restricted to differentiated epithelial cells in vivo. So far, the route of transmission between B cells and the production of progeny virus in the epithelial tissue has remained unclear. Reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemistry analysis of 16 patients with acute infectious mononucleosis (IM) and 25 healthy seropositive donors was performed to detect lytic replication gene products in B lymphocytes of the peripheral blood. Transcriptional activity was found in peripheral blood B lymphocytes (PBLs) for BZLF1 in 88%, BALF2 in 50%, and BcLF1 in 25% of the tested IM patients. All positive results were further confirmed in enriched B-cell populations by antigen determination using immunostaining with the APAAP technique. Furthermore, we detected transcripts for BZLF1 in 72% and for BALF2 in 16% of peripheral B lymphocytes of healthy seropositive donors. In contrast to patients with IM, no signals for BcLF1 were ever found in healthy seropositive donors. In these individuals, lytic replication of EBV is probably restricted by immunologic and gene regulatory mechanisms, whereas in the absence of immunologic control, reflected here by IM patients, the production of infectious virus becomes visible in PBLs.

B-Lymphocytes↗

PubMed1997

Presynaptic bodies ("ribbons"): from ultrastructural observations to molecular perspectives.

The morphological diversity and dynamic aspects of presynaptic bodies are summarised. Molecular characteristics of the presynaptic machinery are discussed and the signals that control the plasticity of the presynaptic bodies are examined. A review is presented of recent findings regarding the physiology of tonically active synapses. The significance of the synaptic bodies and their dynamic changes in retinal and pineal photoreceptors are considered.

Animals↗

PubMed1997

[Must the patient fast before intravascular injection of a non-ionic contrast medium? Results of a controlled study].

PURPOSE: Prospective evaluation of food and fluid restriction before the intravascular injection of a non-ionic contrast medium. MATERIAL AND METHODS: 1000 patients (657 men, 343 women; average age 59 +/- 1/4 5 years) undergoing intravascular contrast injections (CT, phlebography, angiography, urography) were randomly allocated to two groups. Group A had no fluid or solids for at least four hours before the injection (499 cases); group B were allowed unlimited food and fluid (501 cases). Both groups were comparable in all other respects and all were given the non-ionic contrast medium iopamidol (300 mg l/ml). RESULTS: The incidence of acute complications was 3.5%. There was, however, no statistically significant difference between the two groups (p = 0.29). Late adverse reactions were seen in 3.9% patients. There was again no difference between the two groups (p = 0.33). No serious or life threatening complications occurred. CONCLUSION: Restriction of food and fluid before intravascular injection of contrast medium does not reduce the number of adverse side effects. For reasons of patient comfort and compliance, and to achieve adequate hydration, the patient should not fast before injection of contrast.

Adult↗

PubMed1997

[In vitro evaluation of the intravasal Doppler guide wire: determination of hemodynamic effects of stenoses in a flow model].

PURPOSE: In a pulsatile hydraulic model, haemodynamic changes caused by stenoses were assessed using an intravascular Doppler guide wire. MATERIAL AND METHODS: In defined stenoses (25, 50, 75 and 87.5% diameter ratio), and with and without collateral flow, a 0.018 inch (0.46 mm) 12 MHz Doppler guide wire was assessed. Flow velocity measurements were taken 20 mm proximal, in, and 20 mm distal to the stenoses. Average peak velocity (APV) and ratios of pre-/poststenotic velocities and pre-/intrastenotic velocities of APV were compared with the grade of stenosis. The degree of the stenosis calculated by the ratio of the cross-sectional area, using the pre- and intrastenotic APV, was correlated with the actual stenosis. RESULTS: The intrastenotic APV increased significantly (APV proximal to the stenosis 15.15 +/- 4.5 cm/s, intrastenotic APV 134.8 +/- 130.9, p < 0.01, Wilcoxon-Mann-Whitney test). The difference between APV pre- and poststenotic was not significant (p > 0.5). Concerning the grade of stenosis the ratio APV pre-/intrastenotic and the consecutively calculated cross-sectional area stenoses was the best predictor (correlation with the known cross-sectional area stenosis r = 0.94 Pearson). CONCLUSION: Using the Doppler guide wire, APV measurements pre- and intrastenotic enable a reliable quantification of the grade of stenosis. The stenosis calculated via the cross-sectional area correlates significantly with the actual stenosis.

Arterial Occlusive Diseases↗

PubMed1997

Rapid thrombectomy with a hydrodynamic catheter: results from a prospective, multicenter trial.

PURPOSE: To evaluate efficacy and safety of a hydrodynamic rheolytic thrombectomy device for rapid percutaneous treatment of acute thromboembolic occlusions of native lower-extremity arteries and bypass grafts. MATERIALS AND METHODS: In 50 patients, thrombectomy was performed with the rheolytic catheter at four centers. Patients had acute occlusions of native lower-extremity arteries (n = 39) or acute thrombosis of lower-limb bypass grafts (n = 11). Estimated occlusion age was 5 days +/- 5. Mean thrombus length was 15 cm +/- 11. Clinical success was measured on a scale of -3 (deterioration) to +3 (improvement) with established criteria. RESULTS: With the thrombectomy catheter, the majority of thrombus material was removed and antegrade blood flow was reestablished in 45 (90%) patients. Technical success (residual luminal narrowing < 50%) was 52% with use of the device alone. Adjunctive therapy was performed in 45 patients. Clinical improvement after intervention was +3 in 25 (50%) patients, +2 in 10 (20%), +1 in six (12%), and 0 (no improvement) in nine (18%). Clinically unimportant complications related to use of the device were one (2%) distal embolization and two (4%) dissections. Laboratory analysis revealed hemolysis without clinical sequelae. Primary patency rates were 76% after 30 days, 74% after 3 months, and 69% after 1 year. CONCLUSION: The hydrodynamic catheter appears to be safe and effective for rapid thrombectomy.

Aged↗

PubMed1996

Effect of astroglial cell swelling on pH of acidic intracellular compartments.

A variety of pathological conditions lead to swelling of astrocytes, which in turn stimulates ion release by activation of ion channels at the plasma membrane. In the present study, acridine orange and fluorescein isothiocyanate coupled to dextran (FITC-dextran) have been used to examine the effect of cell swelling on pH in acidic compartments of cultured astroglial cells. Both NH4Cl (2 mM) and chloroquine (10 microM), known to alkalinize acidic cellular compartments, led to the expected increase in acridine orange fluorescence intensity. Similar, albeit smaller, effects were elicited by a reduction of extracellular osmolarity (-80 mOsm) and treatment of the cells with glutamate (l mM), manoeuvres which enhanced cell volume. Determination of changes in the FITC-dextran fluorescence ratio (485/440 nm) allowed quantification of the pH changes in lysosomal compartments. Treatment with NH4Cl, reduced extracellular osmolarity and glutamate increased lysosomal pH by 0.65 +/- 0.07, 0.85 +/- 0.14 and 0.25 +/- 0.07, respectively. Measurement of cytosolic pH using 2',7',-bis-(2-carboxyethyl)-5- (and -6) carboxyfluorescein (BCECF) demonstrated a pronounced acidification following cell swelling, observed with both reduced extracellular osmolarity (by 0.23 +/- 0.05 pH units) and 1 mM glutamate (by 0.26 +/- 0.02 pH units). In conclusion, pH within lysosomes and possibly other acidic cellular compartments of astrocytes is increased by cell swelling, which may have important consequences for astrocyte function.

Acridine Orange↗

PubMed1996

The eye of the blue acara (Aequidens pulcher, Cichlidae) grows to compensate for defocus due to chromatic aberration.

By rearing fish in various monochromatic illuminations we investigated (1) the potential for compensation of refractive error due to chromatic aberration, (2) the contributions of the chromatic channels to emmetropization, and (3) the role of color cues in the control of eye growth. Cichlid fish (Aequidens pulcher) were reared for 6 months (12 h light/12 h dark) in monochromatic lights (623.5, 534.1, 485.0 nm; spectral purity 5-10 nm). Light levels were isoirradiant at 1.1.10(12) quanta/s/cm2. Two control groups were reared in white light with down-welling illuminances of 0.2 and 33 lx. Nasotemporal diameters (NTDs) of the eyes were measured in relation to lens size. Due to the oblique axis of highest acuity vision in cichlids, NTD is considered to be a more important dimension than axial length. Variances in NTD were equally small in all rearing groups. NTDs were enlarged with increasing wavelengths of the rearing lights with highly significant values over controls in the red-light group. The wavelength-dependent size of the eyes matched the changes in focal length due to longitudinal chromatic aberration. Complete recovery from eye enlargement was observed after fish reared in red light were exposed to a white light regime for 5 weeks. Small variances in NTD in all groups indicated stringent control of eye growth in the absence of color cues. The reversibility of the increase in NTD in fish reared in red light suggests that the eyes were emmetropized by visually guided mechanisms. Eye size in fish reared in white light was intermediate between the values expected if only blue-sensitive single or the red- and green-sensitive double cones contributed to the control of eye growth. This suggests that all chromatic channels participate in emmetropizing the fish eye.

Adaptation, Ocular↗

PubMed1996

Control of rod retinomotor movements in teleost retinae: the role of dopamine in mediating light-dependent and circadian signals.

In the retinae of lower vertebrates, several morphological changes, including photomechanical movements of rods, cones and pigment epithelium, occur during light and dark adaptation. We studied the contribution of exogenous and endogenous circadian control mechanisms to rod retinomotor movements in the teleost retina and their dependence on an intact dopaminergic system. Blue acara (Aequidens pulcher) were kept under a 12:12 h light/dark cycle. One population of fish remained untreated; another population was treated with 6-hydroxy-dopamine, selectively to destroy dopaminergic cells. Rod positions were determined in semi-thin radial sections. During the normal light/dark cycle, rods were elongated during the day and contracted at night. Rod retinomotor movements persisted during two cycles of continuous darkness. Expected light levels of rod positions were reduced by about 40% in comparison with normal light phases. Adaptation-dependent retinomotor movements and movements driven by an endogenous circadian clock also occurred in dopamine-depleted retinae. No statistically significant differences were observed between dopamine-containing and dopamine-depleted retinae. We conclude that rod retinomotor movements in teleost retinae are controlled by light and by an endogenous circadian clock. Dopamine plays no essential role in the light-dependent and endogenous control of rod retinomotor movements.

Animals↗

PubMed1996

Rod outer segment renewal in the retinae of deep-sea fish.

Outer segment renewal involves the synthesis of disc material in the photoreceptor inner segments, the shedding of the tips of the photoreceptor outer segments, and their phagocytosis by the retinal pigment epithelial cells. It has been suggested that in the retinae of deep-sea fish no renewal of outer segments may take place. In order to assess outer segment renewal in deep-sea fish retinae we counted (i) periciliary vesicles in rod inner segments as a parameter for disc-synthesis activity and (ii) phagosomes in retinal pigment epithelial cells as a parameter of shedding and phagocytosis in 12 species of deep-sea fish with multibank or single bank retinae. We also measured the lengths of rod outer segments in order to evaluate the balance between synthesis and phagocytotic activity. In four of these species (Synaphobranchus kaupi, Nematonurus armatus, Coryphaenoides guentheri and Halosauropsis macrochir) we further recorded size-related changes of these parameters and their relation to the position of a given rod within the banks in the retina. The number of periciliary vesicles was highest in inner segments of the most vitread bank and in the periphery of the retina. Phagosomes were most abundant in retinal pigment epithelial cells of the central retina. Long rod outer segments were most frequently recorded in the peripheral retina indicating that in this region new synthesis may outbalance shedding. Vitread rod outer segments were only slightly longer than sclerad ones. Larger animals had shorter rod outer segments than small ones. We present evidence that rod outer segment renewal takes place in the retina of all deep-sea fish. Vitread rods may be more active in this respect than sclerad ones.

Animals↗

PubMed1996

Intra-vitreal injection of substance P antibodies as an antagonist in the vertebrate (fish) retina.

A method is described for using substance P (SP) antibodies as an antagonist in the retina of a cyprinid fish, the roach (Rutilus rutilus). Antibody solution (10 microliters) injected into the vitreous was found by immunohistochemical localization to penetrate the neural retina up to the level of the inner margin of the inner nuclear layer. Thus, the inner plexiform layer, where SP would normally be released, was well infiltrated. Similar penetration patterns were observed 2 or 24 h after injection. The physiological effectiveness of the antibody was demonstrated indirectly by measuring its effect upon the spatial coupling of the horizontal cells. Previous work suggested that SP stimulates dopamine release which normally uncouples the horizontal cell somata but not the syncytium of their axon terminals. In retinae isolated from antibody-injected eyes, the horizontal cell somata (but not axon terminals) were indeed found to be significantly more strongly coupled, consistent with the blockage of SP-induced, presumably tonic, release of dopamine. The results suggest that peptide antisera can be useful as pharmacological tools to investigate electrophysiological effects of neuropeptides in the retina as in other parts of the central nervous system.

Animals↗

PubMed1996

Horizontal cell spinule dynamics in fish are affected by rearing in monochromatic light.

Blue acaras (Aequidens pulcher, Cichlidae) were reared for 1 yr in white or monochromatic "red", "green" and "blue" lights to study the function and control mechanisms of horizontal cell (HC) spinules in the synaptic pedicles of cones. Ratios of spinules per synaptic ribbon (S/R) were determined in tangential sections in both single and double cones. We found that the S/R ratios in light adapted retinae decreased with decreasing wavelength of the rearing light in all cone types. Conversely, there was an increasing number of incompletely formed spinules with the highest frequency in the blue light group. Dark adaptation resulted in the complete degradation of mature spinules. However, significant numbers of incompletely degraded spinules were observed in the group reared in blue light. Fish reared in blue light which were transferred to white light formed mature spinules when light adapted and still had vestigial spinules when dark adapted. The mechanisms of spinule formation and degradation and the control of spinule dynamics appear to be fully developed in fish reared in monochromatic light. However, long-term chromatic deprivation seems to induce a compensatory modulation of spinule dynamics. A working hypothesis is formulated that interprets the observed effects as manifestations of differences in the activition of dopaminergic interplexiform cells (light adapted) and the sensitivity to glutamate of HCs (dark adapted). Our findings are consistent with the hypothesis that spinules are involved in sign-inverting feedback transmission from HCs to cones.

Adaptation, Ocular↗

PubMed1996

Adaptation-dependent changes of bipolar cell terminals in fish retina: effects on overall morphology and spinule formation in Ma and Mb cells.

We have investigated the effects of light and dark adaptation on the overall morphology of bipolar cell (BC) terminals in sublaminae a and b of the inner plexiform layer after labelling with Lucifer Yellow (LY) and PKC immunostaining using confocal laser scanning microscopy and serially sectioned material for electron microscopy. Three-dimensional reconstructed terminals showed marked adaptation-dependent changes of their morphology. Terminals of mixed rod-cone BCs in sublamina a (Ma BC) were irregular and scalloped in light adapted, but smooth and regular in dark-adapted specimens. Terminals from mixed rod-cone BCs in sublamina b (Mb BCs) exhibited an opposite behaviour. At the ultrastructural level, bipolar terminals in both sublaminae showed fingerlike extensions (spinules) invaginating presynaptic amacrine cell (AC) processes. Sixty-two percent of the dark-adapted Mb terminals in sublamina b showed spinules, whereas 21% of the light-adapted terminals had spinules. By contrast, 50.6% of the light-adapted Ma terminals in sublamina a formed spinules, compared to 17.8% of the dark-adapted Ma terminals in this sublamina. These observations reflect the functional subdivision of the inner plexiform layer in an inner ON-and an outer OFF-centre lamina. Our findings suggest that the synaptic plasticity of BC axon terminals may be due to differences of BC membrane potential, or the activity of AC input onto bipolar terminals. They may contribute to processes of fine tuning regulating the efficiency of AC-BC interaction under varying adaptation conditions.

Adaptation, Ocular↗

PubMed1996

Immunologic properties of Epstein-Barr virus-seronegative adults.

Epstein-Barr virus (EBV) seronegativity is rare in people > 20 years old. However, some persons remain EBV-seronegative for nearly their whole lives. The aim of this study was to examine properties of the immune system of EBV-seronegative adults that could contribute to long-term EBV seronegativity. Therefore, differential blood cell counts and lymphocyte subpopulations were determined, and the production of interferon (INF)-alpha and -gamma and interleukin (IL)-6 and -2 in a whole blood assay was investigated. Whereas no differences in the distribution of lymphocyte subpopulations between EBV-seronegative and -positive adults were found, a significant higher percentage of monocytes in EBV-seronegative adults was observed. Significantly more IFN-alpha and IL-6 were detected in culture supernatants of EBV-seronegative persons after stimulation with Newcastle disease virus. In contrast, no differences in the induction of the lymphokines IFN-gamma and IL-2 were seen. These data suggest that faster and higher production of IFN-alpha and IL-6 amy protect EBV-seronegative adults against EBV infection.

Adult↗

PubMed1996

[Special treatment methods in general practice--legal medicine viewpoint].

There is only one common medical law which is valid for all physicians. No therapy method can claim a special status or special rights. However, due to the considerable differences in training and qualification, the jurisdiction grants special rights to a healer without medical exam (non-medical practitioner) in comparison to a physician. Additionally, a physician has to take into account the limitations by the social legislation when he uses "special treatment methods" to avoid claims for compensation.

Complementary Therapies↗