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Biomedical subjects

H J Wagner

Publications and source records attributed to H J Wagner.

At least 109 records · Page 6Linked to original sources
PubMed1995

[The value of double contrast colon imaging in inadequate colposcopic diagnosis].

PURPOSE: Prospective evaluation of colon double-contrast enemas in patients with incomplete colonoscopy during routine examination. MATERIALS AND METHODS: From 1. February 1993 through 31. January 1994 we prospectively evaluated all patients undergoing a double-contrast barium enema following incomplete colonoscopy in the endoscopy unit of the Department of Surgery of the University Hospital Marburg. The examination was carried out using the typical double-contrast technique at least 24 h after colonoscopy. The results of the barium enema were correlated with the findings at colonoscopy with regard to completion of the diagnostic procedure and additional pathological findings. RESULTS: Of 448 colonoscopies 168 remained incomplete. Sixty patients underwent an additional double-contrast study of the colon. In 43 patients this study was sufficient to complete the diagnostic procedure. Unknown pathological diagnoses were found in 11 patients. In 2 patients an adenocarcinoma and in 9 patients polypoid lesions were detected. CONCLUSION: After incomplete colonoscopy a double-contrast barium enema should be performed to complete the diagnostic examination of the whole colon and to reveal unknown additional pathological findings.

Adenocarcinoma↗
PubMed1994

Dose finding with a novel recombinant plasminogen activator (BM 06.022) in patients with acute myocardial infarction: results of the German Recombinant Plasminogen Activator Study. A study of the Arbeitsgemeinschaft Leitender Kardiologischer Krankenhausärzte (ALKK).

OBJECTIVES: The aim of this study was to determine the appropriate dose of a novel recombinant tissue-type plasminogen activator (BM 06.022) for thrombolysis in patients with acute myocardial infarction. BACKGROUND: BM 06.022 is a mutant of tissue-type plasminogen activator expressed in Escherichia coli that can be given as a single bolus because of a prolonged half-life, which might obviate the need for complicated regimens. METHODS: BM 06.022 given as a single bolus was investigated in 142 patients in a multicenter sequential dose-finding study. Efficacy of the drug was assessed from infarct-related artery patency by coronary angiography. RESULTS: With the first dose of 10 MU of BM 06.022, the predefined minimal 90-min patency of 70% was not achieved, as indicated by the sequential probability ratio test after treatment of 42 patients (group A). The second dose of 15 MU of BM 06.022 was given subsequently in the preset maximum of 100 patients (group B). Angiography 30, 60 and 90 min after the bolus injection of BM 06.022 revealed a patent infarct-related artery (Thrombolysis in Myocardial Infarction trial [TIMI] grade 2 or 3) in 65% and 66%, 73% and 74% and 66% and 75% of patients in groups A and B, respectively. Very early reocclusion up to the 90-min angiogram occurred in 17% and 13%, late reocclusion until predischarge angiography occurred in 7% and 5%, and rescue percutaneous transluminal coronary angioplasty after the 90-min angiogram was performed in 6 and 14 patients in groups A and B, respectively. Plasma fibrinogen decreased from 2.79 g/liter (range 0.94 to 4.75) to 1.69 g/liter (range 0.0 to 3.95) in group A and from 2.54 g/liter (range 0.0 to 5.02) to 0.92 g/liter (range 0.0 to 2.68) in group B. Two bleeding complications requiring transfusion or surgical intervention and one nonfatal intracranial hemorrhage were encountered. Eight patients had a reinfarction, and five patients died, all of cardiac causes. CONCLUSIONS: With BM 06.022 given as a single bolus, a high early patency rate of the infarct-related coronary artery can be achieved. The speed of thrombolysis seems to be superior to standard thrombolytic drugs. The compound warrants further evaluation with respect to safety and efficacy by clinical end points.

Adult↗
PubMed1994

Sex difference in the serostatus of adults to the Epstein-Barr virus.

A total of 1047 adults, aged between 18 and 90 years, including blood donors and surgical patients of the Medical University of Lübeck in Germany, were screened for IgG antibodies to the Epstein-Barr Virus, either by standard indirect immunofluorescence or by a novel enzyme-linked immunosorbent assay (Enzygnost Anti-EBV/IgG, Behring, Marburg, Germany). There was a significant sex difference in the serostatus to the Epstein-Barr virus in adults. Male adults were more likely than females (p < 1%) to be EBV-seronegative. The same trend was seen in both a group of 713 blood donors and 334 surgical patients and when different test methods were used. However, this sex difference was not shown in the sera of 86 pediatric patients of the Medical University of Lübeck tested by indirect immunofluorescence for IgG antibodies to the Epstein-Barr virus. Furthermore, titers of IgG antibodies to Epstein-Barr virus specific antigens of female adults, obtained by the enzyme-linked immunosorbent assay (Enzygnost Anti-EBV/IgG), had significantly higher median values than male adults (p < 5%).

Adolescent↗
PubMed1994

[Relevance of transmission of Epstein-Barr virus through blood transfusion].

In order to investigate the risk of transmission of Epstein-Barr Virus (EBV) by red cell concentrates (RCCs, bottom and top system), we examined 15 EBV-seronegative pediatric patients who received EBV-seropositive red cell concentrates prior to and up to 11 weeks after transfusion. None of these children showed serological or clinical signs of active EBV infection. To further explore this situation we estimated the number of EBV genomes in RCCs in comparison with whole blood units and found a significant reduction (1-2 EBV genomes in one RCC compared with 600-700 in one whole blood unit, p < 0.1%). The use of modern leukocyte depletion systems dramatically reduces the number of EBV-positive cells in RCCs, minimizing the risk of EBV infection. As there were no hints of transmission of EBV in current transfusion practice, the provision of EBV-seronegative RCCs for patients with high risk of infection does not seem to be necessary.

Child↗
PubMed1993

Gonadotropin-releasing hormone, a neuropeptide of efferent projections to the teleost retina induces light-adaptive spinule formation on horizontal cell dendrites in dark-adapted preparations kept in vitro.

The teleost retina receives efferent projections from neurons of the nucleus olfactoretinalis at the base of the olfactory bulbs. These fibres contain gonadotropin-releasing hormone (GnRH) immunoreactive material and are presynaptic to retinal dopaminergic interplexiform cells. We have incubated isolated dark-adapted retinae and eyecup preparations of roach with salmon-GnRH and found an increase in horizontal cell spinule numbers to 70% light-adaptive levels. This effect was blocked by addition of haloperidol to the incubation medium suggesting that GnRH acts via stimulation of the dopaminergic interplexiform cells. We conclude that GnRH containing efferent fibres are capable of inducing light-adaptive changes in the retina and discuss their implication in the control of endogenous rhythms.

Amino Acid Sequence↗
PubMed1993

[Palliative therapy of complex hilar biliary obstructions using self-expanding metal stents].

Implantation of self-expandable metal stents was planned for 21 patients (12 women, 9 men; mean age 64.7 +/- 11.6 [38-80] years) with malignant obstructive jaundice due to complex hilar biliary obstruction (Bismuth II: n = 5, Bismuth III: n = 13, Bismuth IV: n = 1, state after hepaticojejunostomy: n = 2). Stents were implanted bilaterally in 18 patients (one each on the right and left, n = 12; two stents on right, one stent on left, n = 6), one patient had three stents on one side, another had one unilateral stent. Thus there was a 93.3% success rate (46 of 49 planned stent implantations). The mean bilirubin level fell from 14.7 +/- 7.7 mg/dl before stent implantation to 3.9 +/- 5.4 mg/dl afterwards (P = 0.0001). One patient experienced late bleeding with haemorrhagic shock and consumption coagulopathy after a failed drainage attempt. She died despite superselective embolization, operative suturing of the puncture site, and wide-ranging intensive care measures. Procedure-related death rate was thus 4.8%, the 30-day death rate 9.5%. During the follow-up period, averaging 145 +/- 152 (16-529) days, jaundice recurred in six patients (30%) and was successfully treated by re-intervention in five. 13 patients died after a mean survival time of 98 +/- 119 (16-432) days. It is concluded from these data that self-expandable metal stents provide minimally invasive palliative treatment of complex biliary hilar obstruction in the type of case in which plastic stents are known to fail.

Adult↗
PubMed1993

A controlled trial of an expansile metal stent for palliation of esophageal obstruction due to inoperable cancer.

BACKGROUND: Esophageal obstruction due to cancer can produce debilitating dysphagia. Rapid palliation is usually possible with endoscopic placement of a plastic esophageal prosthesis, but this device has a high rate of complications. A new alternative is a metal-mesh stent that collapses to 3 mm in diameter at placement but can then expand up to 16 mm. METHODS: Patients with esophageal carcinoma (39 patients) or malignant extrinsic obstruction (3 patients) were randomly assigned to treatment with either a plastic prosthesis (16 mm in diameter) or an expansile metal-mesh stent. The patients were evaluated every six weeks until death. The degree of palliation was expressed as a dysphagia score and a Karnofsky performance score. RESULTS: Complications were significantly less frequent with the metal stents than with the plastic prostheses (no complications vs. nine; P < 0.001). The dysphagia and Karnofsky scores improved significantly and to a similar degree in both treatment groups. The most common causes of recurrent dysphagia were migration of the plastic prostheses (five patients) and ingrowth or overgrowth of the metal stents by tumor (five patients). The rates of reintervention were similar in both treatment groups, as were the 30-day mortality rates. The period of hospitalization after placement of a prosthesis was significantly longer in the group given plastic prostheses than in the group given metal stents (mean +/- SE, 12.5 +/- 2.1 vs. 5.4 +/- 1.0 days; P = 0.005). Despite their higher initial cost, the metal stents were cost effective because of the absence of fatal complications and the decrease in the hospital stay. CONCLUSIONS: Expansile metal stents are a safe and cost-effective alternative to conventional plastic endoprostheses in the treatment of esophageal obstruction due to inoperable cancer.

Aged↗
PubMed1993

Localization of D2 dopamine receptors in vertebrate retinae with anti-peptide antibodies.

Dopamine plays an important role in modulating various aspects of retinal signal processing. The morphology of dopaminergic neurons and its physiological effects are well characterized. Two classes of receptor molecules (D1 and D2) were shown pharmacologically to mediate specific actions, with differences between individual groups of vertebrates. In an attempt to better understand dopaminergic mechanisms at the cellular level, we used antisera against D2 receptors and investigated the localization of the dopamine D2 receptor in the retinae of rat, rabbit, cow, chick, turtle, frog, and two fish species with immunofluorescence techniques. Antisera were raised in rabbits to two oligopeptides predicted from rat D2 receptor cDNA; one specific for the splice-variant insertion in the third cytoplasmic loop and the other directed towards the extracellular amino terminal region shared by both short and long isoforms. Preadsorption with the synthetic peptide resulted in a significant reduction of label, indicating the presence of specific binding in all species except turtle and goldfish. The pattern of labelling produced by the two antisera was essentially identical; however, the staining obtained with antiserum to the extracellular motif was always more intense. Specific staining was present in photoreceptor inner and outer segments, and in the outer and inner plexiform layers of all species. In mammals and chick, strongly fluorescent perikarya were observed in the ganglion cell layer and at the proximal margin of the inner nuclear layer. Label may be present in the pigment epithelium but could not be established beyond doubt. This pattern of labelling is in accordance with previous observations on D2 receptor localization by means of radioactive ligand binding and in situ hybridization techniques. It suggests that retinal dopamine acts as a neuromodulator as well as a transmitter. In the distal retina, it may reach its targets via diffusion over considerable distances, even crossing the outer limiting membrane; in the inner and outer plexiform layers, conventional synaptic transmission seems to coexist with paracrine addressing of more distant targets, and D2 receptors are expressed by both amacrine and ganglion cells.

Amphibians↗
PubMed1993

Application of DNA filter hybridization and PCR to distinguish between human and non-human tissues of poor quality.

The present report describes a novel approach for the identification of human or non-human specimens after long-term storage in a badly preserved state. The application of the PCR-technique (polymerase chain reaction) using human-specific primers as well as Southern blot (filter) hybridization of the sample DNA to a primate-specific DNA probe enabled us to extend the positive identification beyond the limits of conventional methods such as serological or morphological examinations.

Animals↗
PubMed1993

Microanatomy of the dopaminergic system in the rainbow trout retina.

We have investigated the morphology of dopaminergic interplexiform cells as well as the distribution of two classes of dopamine receptors in the retina of the rainbow trout. Interplexiform cells were visualized using an antiserum against tyrosine hydroxylase and PAP immunocytochemistry. In whole amounts, these cells have a density of between 91 and 182 cells per mm2 with highest values in the lower temporal quadrant. Their cell bodies lie at the inner margin of the inner nuclear layer with only 12-17 cells per retina displaced to the ganglion cell layer. There are three levels of stratification in the inner plexiform layer, one at the distal and proximal borders respectively, and one in the middle. They arise mostly from a radially oriented, stout primary dendrite. Tangential processes are about 1 micron in diameter and show a number of varicosities. The density of processes is greatest in sublayer 5, but no major difference in the general organization is apparent between the three sublayers. In the outer retina, there are two levels of dense ramification confined to the layer of horizontal cells. Light and electron microscopic analysis shows synaptic input to horizontal cells, but not to photoreceptors. The distribution of D1 receptors was assessed by studying the binding pattern of a specific, fluorescent-labelled antagonist, SCH 23390, in unfixed frozen sections. We found displaceable binding in the inner and outer plexiform layers and in the region of horizontal cell perikarya. We used an anti-peptide antibody directed to an extracellular domain of the rat D2 receptor and a fluorescent secondary antiserum to study the localization of D2 receptors. In addition to marked label in both plexiform layers, the outer, and especially the inner segments of rods and cones show specific immunoreactivity. In addition, there is distinct label at the level of the horizontal cell bodies; in the inner retina, specific fluorescence is found in somata of some amacrine cells. The significance of the connectivity pattern and the distribution of the two receptor types is discussed with respect to the role of dopamine in controlling adaptational processes in the outer retina, such as retinomotor movements and changes in horizontal cell morphology and physiology.

Adaptation, Ocular↗
PubMed1993

Spinules: a case for retinal synaptic plasticity.

In both vertebrate and invertebrate nervous systems, a population of synapses is characterized by having finger-like indentations of the postsynaptic membrane that project into the presynaptic terminal. These 'spinules' are often transitory structures, and their presence has been associated with increased synaptic activity. We have studied the functional role of spinules in the fish retina, where they are observed in horizontal cells invaginating cone pedicles, and in synaptic terminals of bipolar cells. In the cone-horizontal cell synaptic complex, spinules are present during light adaptation; their formation is triggered by external light stimuli as well as by endogenous factors. Pharmacologically, spinules are degraded following an increase, and formed in response to a decrease of the transmitter glutamate released by the cone cells. Dopamine, released by interplexiform cells and acting via a D1 receptor-mediated increase in cAMP, and a protein-kinase-C-based mechanism are also capable of inducing spinule formation. Functionally, the presence and absence, as well as the timecourse, of spinule formation during light adaptation is closely correlated with the development of biphasic chromatic responses in a class of cone horizontal cells and the manifestation of colour-opponency in ganglion cells. This suggests that in the outer retina of fish, spinules are mediating feedback activity essential for the coding of antagonistic colour information.

Animals↗
PubMed1993

A prospective, randomized, controlled trial of metal stents for malignant obstruction of the common bile duct.

Endoscopic insertion of biliary stents is the preferred method of palliation for inoperable malignant biliary obstruction; however, migration and clogging are frequent problems with conventional endoprostheses. We sought to determine if expandable metal stents offer improved palliation compared to conventional stents. Sixty-two patients with common bile duct lesions were randomized to receive polyethylene or metal stents. Stents were placed endoscopically or by the combined percutaneous-endoscopic route. Early results (< 1 month) were similar in both groups. Long-term follow-up (n = 28 polyethylene, median: 5 months; n = 27 metal, median: 5 months) showed a higher stent failure rate in the polyethylene (n = 12; 43%) compared to the metal group (n = 6; 22%). The incidence of cholangitis was significantly higher (p < 0.05) in the polyethylene (n = 10; 36%) compared to the metal group (n = 4; 15%). Life-table analysis showed a significantly reduced incidence of stent failure (p = 0.0035) in the metal stent compared to the polyethylene group. The total duration of hospital stay for treatment of stent related problems was significantly higher in the polyethylene (11.8 +/- 3 days) compared to the metal group (4 +/- 1.9 days; p = 0.02). The costs for retreatment because of stent failure were significantly higher in the plastic (DM 5900 +/- 1516) compared to the metal group (DM 2070 +/- 977). As a result, the overall costs (treatment of stent related complications & stents) were higher in the polyethylene group (DM 6000 +/- 1500).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

Plastic endoprostheses versus metal stents in the palliative treatment of malignant hilar biliary obstruction. A prospective and randomized trial.

This prospective and randomized trial sought to compare large-bore plastic endoprostheses (14 French) and self-expanding metal stents (24 French) in the palliative treatment of obstructive jaundice due to biliary hilar malignancies. Twenty patients with Type II-IV (Bismuth classification) hilar obstruction were randomized to treatment with either plastic or metal stents. Both treatment groups were well matched with regard to all assessed clinical criteria before stenting. Stent placement was uniformly successful in the metal group and in 88.9% of the plastic group. Early stent failure (< 30 days) occurred in two patients of the plastic stent group. Longterm (> 30 days), stent failure was observed in 50% of the plastic group and 18.2% of the metal stent group. All differences were not statistically significant. The number of re-interventions required to manage stent-related problems proved to be significantly higher in the plastic group (2.4 +/- 2.6) compared to the metal group (0.4 +/- 0.5). Hospitalization for treatment of stent complications was also significantly higher in the plastic treatment group. The costs calculated for stents and hospital stay for required re-interventions were therefore higher in the plastic stent group. In conclusion, metal stent insertion for palliation of hilar malignancies does not only offer higher success rates and higher patency rates compared to plastic stent insertion, but is also cost-effective since patients require fewer re-interventions.

Aged↗
PubMed1993

[The initial results of the implantation of self-expanding nitinol stents into the esophagus in malignant dysphagia].

Nine patients (mean age 64, range 51-83 years), with dysphagia due to incurable malignant obstruction of the esophagus were treated by the introduction of 10 self-expanding metal endoprostheses (Nitinol stents). All cases were technically and functionally successful. In one patient the stent did not expand completely; it had to be removed and a second introduced. There were no other complications from the stent implantation. During the period of observation of 136 +/- 86 days one stent (11%) was reobstructed by tumor growing into the stent. Two patients died after 60 and 119 days, both with open stents. Early experience with the Nitinol stent indicates that good palliation of malignant dysphagia can be achieved with a much lower complication rate than results from tube implantation. The design and application system of the stent is capable of further improvement.

Aged↗
PubMed1993

[The premedication of PTA. A double-blind and randomized comparison of midazolam/tramadol versus placebo/tramadol].

A prospective, randomised and double blind comparative study of Midazolam/Tramadol or placebo/Tramadol for premedication before PTA was carried out on 40 patients (12 female and 28 male, average age 66.1 +/- 12). The anxiolytic, analgesic and general findings were quantified by means of a visual analogue score. Pre- and peri-interventional blood gas, blood pressure and pulse rates were determined. The complications of the two schemes were compared. 19 patients received Midazolam/Tramadol and 21 placebo/Tramadol. Patient anxiety was reduced significantly from 25.8 +/- 25 to 4.3 +/- 6 by premedication. Significant increase in the pain score during PTA was observed only in the placebo group (4.3 +/- 12.6 to 27.4 +/- 20.9). There was no difference in the incidence of complications and respiratory depression due to the Midazolam/Tramadol combination was not observed.

Aged↗
PubMed1993

[Conventional local intra-arterial fibrinolysis, spray lysis and mechanically accelerated fibrinolysis. An assessment of their position in the spectrum of angioplasty technics].

Intra-arterial local fibrinolysis was performed in 72 patients (51 men, 21 women, mean age 66.8 years) during the course of 78 angioplasties. 11.1% were stage IIa (Fontaine), 38.9% were stage II b, 27.8% were stage III and 22.2% were stage IV. The methods used were conventional fibrinolysis (15.4%), spray lysis (47.4%) and mechanically accelerated fibrinolysis (37.2%). In 66.7% the urokinase dose was < 600,000 I.U., in 17.9% it was > 1,000,000 I.U. Additional balloon dilatation was performed in 72 cases, percutaneous aspiration of thrombo-embolic material in 41 cases and stent implantation in 7 cases. Angiographically the procedure was successful in 90.7%; the Doppler index rose from 0.47 +/- 0.27 to 0.85 +/- 0.3 (p < 0.001). At discharge, staging was: I = 38.9%, IIa = 38.9%, IIb = 5.6%, III = 1.4%, IV = 15.3%. There were no systemic bleeding complications. In 5.1%, complications had to be treated surgically.

Adult↗
PubMed1993

A method for spatio-temporal (4-D) data representation in confocal microscopy: application to neuroanatomical plasticity.

This paper describes a new method for data representation and visualization in four dimensions (three dimensions plus time). Sequential volumes, exhibiting morphological activity, are acquired non-invasively with a confocal scanning laser microscope, where each data set corresponds to a time sample. A pipelined processing includes packing of volumes and specific volume rendering techniques. Subsequent processing in HIS (hue, intensity, saturation)l colour space combines functional, packed images with shaded three-dimensional views. As a result, even subtle changes in morphology become visible and computational time is saved. Experimental findings obtained from investigations of synaptic plasticity in cultured retinal tissue are reported.

Algorithms↗