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Biomedical subjects

U Siebert

Publications and source records attributed to U Siebert.

At least 55 records · Page 3Linked to original sources
PubMed2000

Immunohistological and serological investigation of morbillivirus infection in harbour porpoises (Phocoena phocoena) from the German Baltic and North Sea.

The role of morbillivirus infection as a cause of disease or death in harbour porpoises (Phocoena phocoena) from the German North and Baltic Sea was investigated by serology, histology and immunohistochemistry. Blood and tissue samples of lung, brain and lymph nodes from 74 stranded or by-caught harbour porpoises from German waters were collected between 1991 and 1997. According to dentinal growth layers and body length, animals were grouped into four age classes (neonates, 0-1, 1-4, 4-16 years of age). Formalin-fixed, paraffin-embedded sections were stained by hematoxylin and eosin (HE). Immunohistology was done in all lung tissues using the avidin-biotin-peroxidase technique and a polyclonal canine distemper virus (CDV) nucleoprotein-specific antibody, which cross-reacts with porpoise morbillivirus (PMV) antigen. A virus neutralization assay for detection of (Onderstepoort-strain) CDV- and PMV-specific antibodies was performed. Due to the cytotoxicity of some sera, only titres of 1:20 or greater were considered positive. PMV or CDV-specific neutralizing antibody titres were found in 88 and 50% of the animals, respectively. Titres were always highest against PMV indicating infection with a homologous porpoise virus strain. There were no significant differences in neutralizing antibody titres between animals of the different age groups. No histological lesions specific for morbillivirus infection were detected and by immunohistology all cases were negative for morbillivirus antigen. The absence of morbillivirus antigen and the lack of characteristic morbillivirus-specific lesions showed that morbillivirus infection was not a cause of death or illness in the investigated population. However, the high incidence of PMV-specific antibodies in all age groups indicated a continuous spread of infection with a morbillivirus among harbour porpoises from the German Baltic and North Sea.

Age Factors↗
PubMed2000

[Diagnostic criteria and new classification of the cervical spine syndrome].

OBJECTIVES: Pain and functional disorders of the neck are widely diagnosed as "cervical spine syndrome". As this diagnosis is not able to sufficiently specify the different symptoms, a new classification with five pain syndromes, created empirically, was developed. The aim of this study is to evaluate the predictive values of the diagnostic criteria respectively clinical findings of patients diagnosed with cervical spine syndrome. METHODS: Within the two year time frame of the study all patients diagnosed with "cervical spine syndrome", which presented themselves at the clinic, were included. The statistic analysis was performed in multiple steps: univariate analyses, bivariate variable screening and the use of the logistic regression model. RESULTS: Within two years 653 patients previously diagnosed as suffering from cervical spine syndrome presented at the clinic; 332 of them were included in the study. According to the diagnostic criteria they were attached to one of the five pain syndromes. The statistical analysis showed in 17 of 35 evaluated diagnostic criteria a significant association to one of the five subgroups of the cervical spine syndrome. CONCLUSION: The statistical analyses revealed significant associations between diagnostic criteria which were assessed by clinical examination and the five subgroups of the cervical spine syndrome. The identified predictors represent the typical syndrome-associated diagnostic criteria of a certain syndrome-subgroup.

English Abstract↗
PubMed2000

Reproducibility of neointima quantification with motorized intravascular ultrasound pullback in stented coronary arteries.

BACKGROUND: Intravascular ultrasound (IVUS) imaging has shown excellent reproducibility immediately after coronary stent implantation. However, the variability of measurements in lesions late after stent implantation, when neointima formation is present, has not been studied. Neointimal tissue is generally low echogenic and thus difficult to quantify. We therefore sought to analyze the reproducibility of morphometric measurements late after stent implantation. METHODS AND RESULTS: Fifty consecutive patients were investigated 6 months after Palmaz-Schatz stent implantation (motorized catheter pullback 0.5 mm/s). Two experienced investigators independently identified the stent area, lumen area, and neointimal area at different sites within the stent. Planimetric measurements were performed with commercially available software. Correlation coefficient and mean difference for corresponding measurements were calculated for the intraobserver and interobserver comparisons. Variability for the intraobserver and interobserver comparisons was similar. Observer agreement regarding the presence of neointimal hyperplasia was as high as 71% (interobserver comparison 62%). The mean difference for neointima area was 0.06 +/- 1.5 mm(2) (-0.6 +/- 1.5 mm(2)); mean differences for lumen area were 0.02 +/- 0.19 mm(2) (0.03 +/- 0.17 mm(2)) and for stent area 0.01 +/- 0.09 mm(2) (-0.02 +/- 0.12 mm(2)) (values for interobserver comparison are given in parentheses). Correlation between measurements was high for all structures: correlation coefficients were 0.66 (0.69) for neointima, 0.94 (0.95) for lumen, and 0.95 (0. 91) for stent area. CONCLUSIONS: Morphometric measurements of IVUS investigations with motorized IVUS pullback late after stent placement show good reproducibility. Intraobserver variability and interobserver variability are low. Differences for corresponding measurements were more pronounced for neointima area. Motorized catheter pullback guarantees high reliability of IVUS measurements and should be used routinely for clinical IVUS studies.

Aged↗
PubMed2000

Genital diseases in the peruvian dusky dolphin (Lagenorhynchus obscurus).

Ovarian cysts and one ovarian tumour, uterine tumours, vaginal calculi, abscesses of the broad ligament or undetermined testicular lesions were observed in 25 out of 502 female and male dusky dolphins (Lagenorhynchus obscurus) caught off Peru in 1985-1987 or 1993-1994. Tentative or definitive diagnoses included Graafian follicle cysts, luteinized cyst, ovarian parasitic granulomatous inflammation, dysgerminoma, leiomyoma, fibroleiomyoma and chronic fibrino-suppurative inflammation of the broad ligament. All lesions described represented first reports for L. obscurus, and the diagnosis of dysgerminoma was the first in a cetacean. It is also the first time that trematode eggs have been reported in the ovaries of cetaceans and that a vaginal calculus has been encountered in a sexually immature cetacean. The finding of struvite as a major component in two vaginal calculi suggested an infectious aetiology. Of 11 mature females with ovarian tumour or cysts or uterine tumours, only one (9.1%) was pregnant, i.esignificantly less than the expected pregnancy rate (53.3% in a random sample of Peruvian dusky dolphins). Several females with ovarian or uterine lesions and males with aberrant testes were large animals. It is possible that some of these lesions were associated with normal senescence of the reproductive system.

Animals↗
PubMed1999

Predictors of reduced coronary flow reserve in heart transplant recipients without angiographically significant coronary artery disease.

BACKGROUND: Determination of coronary flow reserve (CFR) is increasingly used to assess the functional significance of cardiac allograft vasculopathy. Although the relation between CFR and angiographically defined vasculopathy has been studied extensively, little is known about other factors determining CFR in heart transplant recipients without significant lesions by coronary angiography. METHODS: Sixty consecutive patients were studied 0.5 to 148 months after heart transplantation with intracoronary Doppler and intravascular ultrasound. An endothelium-independent CFR< or =2.5 was defined as abnormal. Stepwise logistic regression analysis was used to identify factors (demographic data of donor and recipient, lipid profile, epicardial vessel morphology by intravascular ultrasound, left ventricular hypertrophy, acute rejection episodes, and hemodynamics) potentially associated with a reduced CFR. RESULTS: Only the presence of left ventricular hypertrophy (48% vs. 14%, P=0.007 and P=0.023, bivariate and multivariate analysis, respectively) and higher donor ages (41+/-12 vs. 29+/-11 years, P=0.002 and P=0.013, bivariate and multivariate analysis, respectively) showed an independent association with an abnormal flow reserve. CFR in patients with left ventricular hypertrophy was reduced due to higher baseline flow velocities (27+/-11 vs. 20+/-6 cm/sec, P=0.004). Furthermore, resting flow velocity increased as a function of donor age (r=0.264, P=0.047), while hyperemic flow velocity was not different. Other patient characteristics and hemodynamics did not affect CFR. CONCLUSION: The presence of left ventricular hypertrophy and higher donor ages independently contribute to a reduced CFR in patients after heart transplantation. This reduction in CFR is due to elevated baseline flow velocities rather than to a change in hyperemic flow velocities. These findings should be taken into account for the interpretation of reduced CFR values obtained by intracoronary Doppler in heart transplant recipients without angiographically overt coronary lesions.

Adult↗
PubMed1999

Prevention of osteoporosis after cardiac transplantation: a prospective, longitudinal, randomized, double-blind trial with calcitriol.

BACKGROUND: Accelerated bone loss is a well-recognized complication after cardiac transplantation (HTx) due to immunosuppressive therapy. The purpose of this prospective, longitudinal, randomized, placebo-controlled, double-blind study was to investigate the effect of calcitriol (1,25-dihydroxyvitamin D3) in the prevention of bone loss and fracture rate after HTx. METHODS: Basic therapy included 1000 mg of calcium daily and sex hormone replacement in hypogonadal patients. A total of 132 patients (111 male, 21 female; mean age: 51+/-10 years; 35+/-25 months after HTx) were randomized to 0.25 microg of calcitriol or placebo. Bone mineral density (BMD, g/cm2; T score, %) of the lumbar spine and x-rays for the assessment of vertebral fractures were performed at baseline and after 12, 24, and 36 months. Biochemical indexes of mineral metabolism were measured every 3 months. RESULTS: Overall BMD was significantly decreased after HTx (T score 87+/-13%). BMD increased continuously within the study period in the calcitriol group (1 year: 2.2+/-4.8%; 2 years: 3.9+/-5.4%; 3 years: 5.7+/-4.4%) as well as in the placebo group (1 year: 1.8+/-4.9%; 2 years: 3.7+/-6.5%; 3 years: 6.1+/-7.8%) without statistical difference between the groups. Fracture incidence was low during the study interval (1 year: 2.0%; 2 years: 3.4%; 3 years: 0%). Hypogonadism (20%) was associated with a lower BMD (78+/-12% vs. 88+/-12%; P<0.01) and a higher increase (35%) after hormone replacement in comparison to normogonadal patients. Increased intact parathyroid hormone and bone resorption markers decreased significantly during therapy. CONCLUSIONS: Calcium supplementation and sex hormone replacement in hypogonadism proved a sufficient long-term prevention therapy to improve decreased BMD and to prevent fractures after HTx. Besides immunosuppression, both concomitant hypogonadism and secondary hyperparathyroidism play a major role in the long-term bone loss and should therefore be monitored and treated adequately. Low-dose calcitriol demonstrated no significant extra benefit regarding BMD and fracture rate in the long-term period after HTx.

Adult↗
PubMed1999

Diagnostic and prognostic value of serial dobutamine stress echocardiography for noninvasive assessment of cardiac allograft vasculopathy: a comparison with coronary angiography and intravascular ultrasound.

BACKGROUND: Routine methods for surveillance of cardiac allograft vasculopathy (CAV) are coronary angiography and intravascular ultrasound (IVUS). This study analyzed the diagnostic and prognostic value of dobutamine stress echocardiography (DSE) for noninvasive assessment of CAV. METHODS AND RESULTS: In 109 heart transplant recipients, 333 DSEs were compared with 285 coronary angiograms and 199 IVUS analyses. Studies were repeated after 1, 2, 3, 4, and >/=5 years in 88, 74, 37, 18, and 7 patients, respectively. Resting 2D echocardiography detected CAV defined by IVUS and angiography with a sensitivity of 57% (specificity 88%). DSE increased the sensitivity to 72% (P=0.002). M-mode analysis increased the sensitivity of 2D rest and stress analysis (P=0.001, 0.004). Cardiac events occurred after 1.9% of normal stress tests by 2D analysis (combined 2D and M-mode: 0%), compared with 6.3% (3.8%) of normal resting studies. Worsening of serial DSE indicated an increased risk of events compared with no deterioration (relative risk 7.26, P=0.0014). Serial deterioration detected by stress only was associated with a higher risk of events than changes evident from resting studies (relative risk 3.06, P=0.0374). CONCLUSIONS: DSE identifies patients at risk for events and facilitates monitoring of CAV. A normal DSE predicts an uneventful clinical course and justifies postponement of invasive studies. The prognostic value of DSE is comparable to that of IVUS and angiography.

Adrenergic beta-Agonists↗
PubMed1999

Epizootic of morbilliviral disease in common dolphins (Delphinus delphis ponticus) from the Black sea.

Forty-seven common dolphins (Delphinus delphis ponticus) were stranded on the northern shores of the Black Sea between mid-July and early September 1994, more than in previous or subsequent years. Two of the 47 dolphins were examined in detail to try to determine the cause of the increased stranding rate. Their lesions included broncho-interstitial pneumonia with type II epithelial cell hyperplasia and multinucleate syncytial cells, neuronal necrosis, gliosis, and non-suppurative meningitis of the brain, necrotic stomatitis, gastroenteritis and cholangitis, and lymphoid depletion of the spleen and lymph nodes. The diseased tissues stained positive in an immunoperoxidase test, using a polyclonal antiserum to measles virus as the primary antibody, and electron microscopy showed that they contained regularly-shaped intranuclear particles about 22 nm in diameter. They were positive by the polymerase chain reaction (PCR) for the nucleoprotein gene of morbillivirus. However, there was no evidence of morbillivirus in frozen tissues either by virus isolation or by antigen capture ELISA. The concentration of sigma DDTS in the blubber of both dolphins was about 50 to 100 times higher than the levels in toothed cetaceans from the North Sea, North Atlantic Ocean, and Baltic Sea. The lesions were consistent with those found in other species with morbilliviral disease, and the positive immunoperoxidase test, PCR and electron microscopical examination confirmed a morbillivirus as the primary cause of these lesions.

Animals↗
PubMed1999

IVUS analysis of the acute and long-term stent result using motorized pullback: intraobserver and interobserver variability.

Intravascular ultrasound imaging has become an established method for analysis of intra-coronary stents. We analyzed the reproducibility of morphometric measurements immediately and late after stent implantation and the variability in the selection of predefined sites during motorized catheter pullback. Fifty consecutive patients were investigated immediately and 6 months after Palmaz-Schatz stent implantation (motorized catheter pullback 0.5 mm/sec; 2.9 Fr; 30-MHz transducer). Two experienced investigators independently identified the proximal and distal reference, stent inlet, stent outlet, and the minimal in-stent area in each imaging run. The longitudinal distance between corresponding measurement sites was calculated. Lumen, stent, and vessel area were assessed by planimetry, mean difference was calculated. Long-term reproducibility was analyzed by comparison of measurements made at predefined sites within the stent, immediately and late after implantation. Observer agreement in identification of predefined measurement sites was high. Longitudinal distance between corresponding measurement sites was low and pronounced for the minimal in-stent lumen area. Variabilities for the intra- and interobserver comparison were similar. Values for interobserver comparison were given in brackets. Acute after stent implantation, the variability for the reference proximal was 4.9% (0.4%), distal -1.0% (-4.2%), minimal in-stent lumen -0.5% (1.3%). At follow-up, variability for the reference proximal was -11.0% (-2.2%), distal -1.0% (-2.3%), minimal in-stent lumen 1.9% (6.1%). Long-term reproducibility for the proximal stent inlet was 2.7% (observer 1) and -0.4% (observer 2), for the distal stent outlet 1.3% (observer 1), -3.0% (observer 2), respectively. IVUS investigations with motorized IVUS pullback in stented coronary segments show a low intra- and interobserver variability, both immediately and late after stent implantation. Absolute and relative area differences are low. Long-term reproducibility of measurements within predefined stent sites was high. Motorized catheter pullback guarantees high reliability of IVUS measurements and should be routinely used for clinical IVUS studies.

Blood Vessel Prosthesis Implantation↗
PubMed1999

Thymic cysts in harbor porpoises (Phocoena phocoena) from the German North Sea, Baltic Sea, and waters of Greenland.

Thymic cysts have not been previously reported in harbor porpoises (Phocoena phocoena). Two hundred forty stranded or "by-caught" harbor porpoises originating from the German North Sea and Baltic Sea and 14 animals from the waters of Greenland were necropsied. Thymuses of 78 porpoises of the North Sea and Baltic Sea were considered suitable for histopathologic examination based on the extent of postmortem autolysis. Immunohistochemistry using an anti-cytokeratin antibody was employed to demonstrate thymic epithelial structures in selected cases. Thymic macrocysts were rare and were only found in animals > or =7 years of age. Thymic microcysts, lined by a single cytokeratin-positive cell layer, were common in involuting thymuses, and the prevalence increased with advancing age. Thymic cysts might have arisen from degenerating Hassall's corpuscles or condensed epithelial reticulum. Thymuses were easily identified macroscopically in most adult healthy harbor porpoises, suggesting that physiological thymic involution proceeds slowly in this species.

Animals↗
PubMed1999

Rhizopusmycosis in a harbor porpoise from the Baltic Sea.

A case of systemic mycosis due to a Rhizopus sp. infection is described in a dead-stranded, 10-yr-old, male harbor porpoise (Phocoena phocoena) found on the beach of Neustadt, Schleswig-Holstein on the Baltic Sea (Germany). At necropsy, granulomatous mycotic lesions in brain, lung, kidneys, testis, and draining lymph nodes were found. In addition, a focal ulcerative gastritis of the first stomach, due to a nematode infection, was present and is suspected to be the portal of entry for the fungus.

Animals↗
PubMed1999

[Parameter of evidence-based medicine in health care economics].

In the view of scarcity of resources, economic evaluations in health care, in which not only effects but also costs related to a medical intervention are examined and a incremental cost-outcome-ratio is build, are an important supplement to the program of evidence based medicine. Outcomes of a medical intervention can be measured by clinical effectiveness, quality-adjusted life years, and monetary evaluation of benefits. As far as costs are concerned, direct medical costs, direct non-medical costs and indirect costs have to be considered in an economic evaluation. Data can be used from primary studies or secondary analysis; metaanalysis for synthesizing of data may be adequate. For calculation of incremental cost-benefit-ratios, models of decision analysis (decision tree models, Markov-models) often are necessary. Methodological and ethical limits for application of the results of economic evaluation in resource allocation decision in health care have to be regarded: Economic evaluations and the calculation of cost-outcome-rations should only support decision making but cannot replace it.

Costs and Cost Analysis↗
PubMed1998

Heavy metals in dolphins stranded on the French Atlantic coast.

Heavy metal concentrations (total and organic Hg, Ti, Cr, Cu, Zn, Cd and Pb) were determined in the muscle, liver and kidney of 36 dolphins stranded on the French Atlantic coast between 1977 and 1990: 29 common dolphins Delphinus delphis, five bottlenose dolphins Tursiops truncatus and two striped dolphins Stenella coeruleoalba. Total Hg concentration in the liver increased with age, while relative methylmercury concentration decreased, reflecting the existence of a slow demethylation process. To a lower extent, a similar pattern was observed in the kidney and muscle. No age-related increase was found for other heavy metals, although the highest levels for Cd and Cr were always found in adults. No difference in contamination could be detected between the 1977-1980 and 1984-1990 periods.

Animals↗
PubMed1998

Identification and molecular characterization of beta-hemolytic streptococci isolated from harbor porpoises (Phocoena phocoena) of the North and Baltic Seas.

The present study was designed to identify and comparatively investigate 35 beta-hemolytic streptococci isolated from stranded harbor porpoises or from animals caught in fishing nets of the North and Baltic seas. According to biochemical and serological data and to lectin agglutination tests with the lectin of Arachis hypogaea, all 35 isolates could be classified in Lancefield's serological group L and could be identified as Streptococcus dysgalactiae subsp. dysgalactiae. All 35 group L streptococci were uniformly sensitive to most of the antibiotics tested. To further analyze the epidemiological relationship, the isolates were subjected to macrorestriction analysis of their chromosomal DNA by pulsed-field gel electrophoresis. Digestion of the chromosomal DNA with the restriction enzymes SmaI and ApaI revealed that most of the group L streptococci seemed to be apparently identical or related. These results indicate that one clone or at least related group L streptococcal clones play an important role for infections of harbor porpoises of the North and Baltic seas. This might possibly be caused by a direct transfer of the bacteria from animal to animal.

Agglutination↗
PubMed1997

[Prospective study of the frequency and extent of donor-transmitted coronary disease after heart transplantation by intravascular ultrasound].

PROBLEM AND OBJECTIVE: Cardiac allograft vasculopathy influences long-term survival of patients after heart transplantation. Donor-transmitted coronary artery disease may contribute to the further development of cardiac allograft vasculopathy. The aim of this study was to characterize by intracoronary ultrasound the extent and frequency of transmitted coronary artery disease. PATIENTS AND METHODS: Intravascular ultrasound studies were performed at routine angiography in 33 patients (26 men, 7 women, mean age 51 [23-69] years) early after heart transplantation. Plaque morphology was analysed in 153 coronary segments of 52 epicardial coronary arteries. RESULTS: Relevant atherosclerosis (defined as maximal plaque thickness > or = 0.5 mm in at least one coronary segment) was found in 17 patients (52%), while angiography showed irregularities in only 7 patients (21%). Maximal plaque thickness in patients with relevant atherosclerosis was 1.13 +/- 0.32 mm, mean plaque index was 19.2 +/- 10.2%. Plaque formation was eccentric, and plaques were predominantly located in proximal segments. Morphologic changes affecting more than one segment were found in 52% of the patients. Comparing clinical factors, only donor age predicted the degree of atherosclerosis. CONCLUSIONS: In more than one half of the patients studied early after heart transplantation, Intravascular ultrasound revealed epicardial atherosclerotic lesions which were incompletely identified by coronary angiography. The degree of atherosclerosis was closely related to donor age. The potential influence of donor transmitted coronary artery disease on the progression of transplant coronary artery disease requires further longitudinal studies.

Adult↗