Search PubMed⌕ Search

Biomedical subjects

H J Wagner

Publications and source records attributed to H J Wagner.

At least 37 records · Page 2Linked to original sources
PubMed2001

Multiplanar reconstructions and three-dimensional imaging (computed rotational osteography) of complex fractures by using a C-arm system: initial results.

With use of a calibrated angiographic C-arm system and a postprocessing workstation, the authors acquired volume data sets from two-dimensional digital projection images obtained during a C-arm rotation around the patient axis. Multiplanar reconstruction and three-dimensional images of complex fractures were reconstructed and compared with spiral computed tomographic studies in a cadaveric pig study and in eight patients. Computed rotational osteography provided high-resolution multiplanar reconstruction and three-dimensional images of complex fractures.

Animals↗
PubMed2001

MR hydrometry to assess exocrine function of the pancreas: initial results of noninvasive quantification of secretion.

PURPOSE: To evaluate magnetic resonance (MR) hydrometry, a method of quantifying fluid amounts by using MR imaging, for assessing the exocrine function of the pancreas after stimulation with secretin. MATERIALS AND METHODS: Images were obtained with a single-shot turbo spin-echo sequence by using a 1.0-T magnet with a quadrature body coil. Image postprocessing and evaluation were performed at an external workstation by using a specially designed histogram algorithm that translates the MR signal intensity of duodenal filling into an actual amount of duodenal fluid. This algorithm was tested in vitro and in vivo. Finally, MR hydrometry results in five patients were correlated with those of the secretin-cerulein test. RESULTS: The phantom measurements showed a high correlation (r = 0.99) between the actual amount of fluid in the imaging volume and the calculated results. In vivo, the ability of MR hydrometry to enable exact quantification of fluid amounts was demonstrated. In correlating the signal intensity of duodenal filling with the exact amount of additional fluid in the duodenum in volunteers, a coefficient of 0.043 gray tones per pixel per milliliter was calculated. The correlation (r) between secretin-stimulated duodenal fluid output estimated by using tube aspiration and that estimated by using MR hydrometry was 0.946 (P <.05). CONCLUSION: MR hydrometry is a promising noninvasive method of assessing fluid output as a measure of exocrine pancreatic function.

Algorithms↗
PubMed2001

Comparative trial of local pharmacotherapy with L-arginine, r-hirudin, and molsidomine to reduce restenosis after balloon angioplasty of stenotic rabbit iliac arteries.

PURPOSE: To determine if local application of L-arginine, r-hirudin, or molsidomine significantly reduces restenosis after balloon angioplasty in stenotic rabbit iliac arteries. MATERIALS AND METHODS: Thirty-one male cholesterol-fed New Zealand white rabbits underwent balloon dilation of both common iliac arteries to induce arterial stenosis. Four weeks later, one stenotic iliac artery was simultaneously dilated and received local application of L-arginine (210 mg/mL, n = 7), r-hirudin (0.5 mg/mL, n = 8), or molsidomine (0.2 mg/mL, n = 8) with a channeled balloon catheter. On the contralateral side, 0.9% saline was injected as a control. In eight sham animals, saline was applied to one iliac artery and balloon dilation to only the contralateral artery. Six weeks after local treatment, vessels were harvested, and computerized morphometric and immunohistologic analyses were performed. RESULTS: Application of drugs resulted in a significant reduction of neointimal area as follows: 53% with L-arginine (1.01 mm(2) vs. 2.17 mm(2), P <.05), 43% with molsidomine (1.04 mm(2) vs. 1.89 mm(2), P <.05), and 20% with r-hirudin (1.79 mm(2) vs. 2.24 mm(2), P <.05). Infusion of saline led to a significant increase (50%, 1.21 mm(2) vs. 1.93 mm(2), P <.05) in neointimal area compared with balloon dilation alone. Immunohistologic findings showed a significant reduction of macrophages (5.0% vs. 10.2%, P <.05) and proliferating cells (6.2% vs. 10.6%, P <.05) in the neointima after local application of L-arginine. CONCLUSION: Reduction of neointimal area was significant for L-arginine and molsidomine but not for r-hirudin. Saline infusion caused significant arterial trauma, resulting in additional neointimal proliferation.

Administration, Topical↗
PubMed2001

Sensory brain areas in mesopelagic fishes.

Four areas of the brain that receive primary projections from chemical senses ([1] olfactory bulb, [2] facial and vagal lobes), the eye ([3] optic tectum), and somato- and mechanosensory systems such as the lateral line, vestibular and auditory systems ([4] trigeminal and octavolateral regions) have been studied and relative size differences used to deduce the sensory specializations of 67 species of mesopelagic fishes. One type of analysis used the average relative volumes of brain areas and identified 'specialists' with only one brain area above-average (36%), species 'dominated' by two sensory brain regions (49%), and generalists (15%), with three areas above-average. In addition, a cluster analysis was performed that separated 49 species which were mostly visually oriented from 18 non-visual species, among which 16 were characterized by an association of above-average trigeminal/octavolateral and gustatory areas, and a single species with a dominant olfactory bulb. The results support the idea that these species occupy a rich sensory environment for which the absence of sunlight is compensated by chemical and mechanosensory stimuli as well as by bioluminescent signals. This has lead to the development of specializations for the perception of single stimulus-modes, most notably for the visual system, as well as for combinations of various receptors and central processing areas, with a preference for associating either the chemical senses, including the olfactory and facial/vagal systems, or the trigeminal/octavolateral systems.

Animals↗
PubMed2001

Brain areas in abyssal demersal fishes.

Four areas of the brain which receive primary projections from chemical senses ([1] olfactory bulb, [2] gustatory area including facial and vagal lobes), the eye ([3] optic tectum), and mechanosensory, and-hair-cell based systems i.e. the lateral line, vestibular and auditory systems ([4] trigeminal and octavolateral regions) have been studied and relative size differences used to make deductions on the sensory preferences of 35 fish species living on or near the bottom of the deep sea. Furthermore the relative volumes of the telencephalon and the corpus cerebelli were determined. Two evaluation modes were applied: (1) the relative mean of each system was calculated and species with above-average areas identified; (2) a cluster analysis established multivariate correlations among the sensory systems. The diversity of sensory brain areas in this population of fish suggests that the benthic and epibenthic environment of the abyss presents a rich sensory environment. Vision seems to be the single most important sense suggesting the presence of relevant bioluminescent stimuli. However, in combination the chemical senses, smell and taste, surpass the visual system; most prominent among them is olfaction. The trigeminal/octavolateral area indicating the role of lateral line input and possibly audition is also well represented, but only in association with other sensory modalities. A large volume telencephalon was often observed in combination with a prominent olfactory system, whereas cerebella of unusually large sizes occurred in species with above-average visual, hair-cell based, but also olfactory systems, confirming their role as multimodal sensorimotor coordination centers. In several species the predictions derived from the volumetric brain analyses were confirmed by earlier observations of stomach content and data obtained by baited cameras.

Adaptation, Physiological↗
PubMed2001

[Analysis of the genetic structure of the breeding nucleus of the Russian population of purebred Thoroughbred horses at the Extension locus using molecular DNA typing].

Results of the first in Russia survey of the gene pool of the breeding nucleus of the Russian population of thoroughbred horses by means of PCR analysis of the E (Extension) locus MC1R gene mutations are presented. The data on the structure of breeding populations from the leading stud farms Voskhod and Oros with regard to color phenotypes as well as genotype and allele frequencies are presented. The population structure parameters are discussed with respect to possible specific features of microevolution processes.

Animals↗
PubMed2000

Quantitative PCR analysis of different splice forms of NFAT5 revealed specific gene expression in fetal and adult brain.

To investigate sequences or mutations associated with neurodegenerative disorders, we performed analyses for the NFAT5 gene, which is located in the candidate region for the autosomal dominantly inherited spinocerebellar ataxia type 4 (SCA4). PCR based expression analyses detected NFAT5 transcripts with alternative splicing in 27 fetal and adult human tissues. Interestingly, by using quantitative methods on cDNA from fetal and adult human brain a significant difference at the expression level for one splice form could be shown.

Adult↗
PubMed2000

Effects of long-term spectral deprivation on the morphological organization of the outer retina of the blue acara (Aequidens pulcher).

To investigate the developmental plasticity of colour vision, we reared fish with a trichromatic cone system (Aequidens pulcher) under three near-monochromatic lights, differentially stimulating each spectral cone type from the larval stage to the age of at least one year. Control conditions comprised white lights of two intensities. The treatments did not affect the visual pigments, hut led to significant changes in cone outer segment lengths. Furthermore, in the blue-reared group the density of single cones within the retina was reduced by two-thirds after 18 months of exposure, while no changes were observed in the other groups. The connectivity of cone horizontal cells with the single cones was influenced by the intensity and spectral composition of the rearing lights: H1 cells were more sensitive to the spectral component, whereas H2 cells responded to intensity cues. In the blue-light group the dynamics of horizontal cell synaptic spinule formation and degradation were severely compromised. These observations show that long-term spectral deprivation leads to significant morphological changes at the level of photoreceptors and horizontal cells. While the reactions of photoreceptors may be interpreted mostly in terms of compensation, the functional consequences of the changes observed on the horizontal cell level remain to be determined electrophysiologically.

Animals↗
PubMed2000

Foveate vision in deep-sea teleosts: a comparison of primary visual and olfactory inputs.

The relative importance of vision in a foveate group of alepocephalid teleosts is examined in the context of a deep-sea habitat beyond the penetration limits of sunlight. The large eyes of Conocara spp. possess deep convexiclivate foveae lined with Müller cells comprising radial shafts of intermediate filaments and horizontal processes. Photoreceptor cell (171.8 x 10(3) rods mm(-2)) and retinal ganglion cell (11.9 x 10(3) cells mm(-2)) densities peak within the foveal clivus and the perifloveal slopes, respectively, with a centro-peripheral gradient between 3:1 (photoreceptors) and over 20:1 (ganglion cells). The marked increase in retinal sampling localized in temporal retina, coupled with a high summation ratio (13:1), suggest that foveal vision optimizes both spatial resolving power and sensitivity in the binocular frontal visual field. The elongated optic nerve head is comprised of over 500 optic papillae, which join at the embryonic fissure to form a thin nervous sheet behind the eye. The optic nerve is divided into two axonal bundles; one receiving input from the fovea (only unmyelinated axons) and the other from non-specialized retinal regions (25% of axons are myelinated), both of which appear to be separated as they reach the visual centres of the central nervous system. Comparison of the number of primary (first-order) axonal pathways for the visual (a total of 63.4 x 10(6) rod photoreceptors) and olfactory (a total of 15.24 x 10(3) olfactory nerve axons) inputs shows a marked visual bias (ratio of 41:1). Coupled with the relative size of the optic tecta (44.0 mm3) and olfactory bulbs (0.9 mm3), vision appears to play a major role in the survival of these deep-sea teleosts and emphasizes that ecological and behavioural strategies account for significant variation in sensory brain structure.

Animals↗
PubMed2000

Prospective comparison of magnetic resonance sialography and digital subtraction sialography.

We sought to compare the diagnostic utility of magnetic resonance sialography (MRS) and digital subtraction sialography (DSS) in patients with suspected sialolithiasis or sialadenitis. Sixteen consecutive patients (4 female and 12 male, mean age 51+/-16 years) with suspected sialolithiasis or sialadenitis underwent DSS by a standard technique and MRS. MRS was obtained with a T2-weighted single-shot TSE sequence (TR/TE 2800/1100 msec, acquisition time 7 seconds) using a quadrature head (n = 16) and a surface coil (n = 8). Nineteen symptomatic glands were investigated with DSS: eight submandibular glands in 6 patients (two bilateral) and unilateral parotid glands in 11 patients. MRS was always carried out to visualize gland ducts bilaterally. The ductal system was visualized in all glands examined by MRS. DSS depicted the ductal system in all 11 parotid glands, but only 4 of the 8 submandibular glands (50%). Sialolithiasis was diagnosed in three cases (one parotid, two submandibular glands) by MRS and in two cases by DSS. DSS demonstrated tertiary branching ducts and MRS secondary branching ducts. MRS is able to visualize the ductal system of the parotid and submandibular gland noninvasively and is thus not dependent on successful cannulation of the orifice of the ductal system. Our preliminary data indicate that MRS is useful for diagnosing sialolithiasis. MRS allows diagnosis of sialadenitic changes, but DSS achieves a better diagnostic performance due to higher spatial resolution.

Adolescent↗
PubMed2000

Management of nonfunctioning islet cell carcinomas.

Tumors arising from the pancreatic islet cells are rare and represent a heterogeneous group of benign or malignant lesions. Most tumors present with well characterized syndromes, whereas others appear to be nonfunctioning. The clinical features of 11 men and 7 women with nonfunctioning islet cell carcinomas operated on between 1983 and 1998 were reviewed. The median patient age was 53.5 years (range 26-74 years). The most frequent presenting symptoms were abdominal pain (13 patients), weight loss (7 patients), and obstructive jaundice (4 patients). Gut hormone profiles were normal in all patients. Abdominal sonography and computed tomography localized the tumor in 17 patients, and correct prediction of an endocrine tumor was achieved in 12 patients. Six of seven patients showed a hypervascular tumor upon angiography, and seven of eight patients preoperatively had positive somatostatin receptor scintigraphy. At operation, regional or distant metastases were present in 15 (83%) and 6 (33%) patients, respectively. Eleven patients underwent potentially curative resections, and the remaining seven patients were managed palliatively by resection (four patients) or bypass procedures (three patients). Three patients had up to three more resection for metastases. Eight patients received postoperative octreotide, interferon alpha therapy, or both. The overall cumulative 5- and 10-year survival rates were 65.4% and 49.1%, respectively. Of the 11 patients who underwent curative resection, 10 were alive after a median follow-up of 63 months (range 7-180 months), but only 5 are free from disease. Although surgical cure is rare in nonfunctioning islet cell carcinomas, significant long-term palliation can be achieved in a large proportion of patients with an aggressive surgical approach and, when indicated, additional medical therapy.

Adult↗
PubMed2000

Effect of melatonin agonists and antagonists on horizontal cell spinule formation and dopamine release in a fish retina.

The crucian carp retina was used to study the effects of the melatonin antagonist p697 (N-pentanoyl 2-benzyltryptamine) and the melatonin agonists [+]- and [-]-AMMTC (N-acetyl-4-aminomethyl-6-methoxy-9-methyl-1,2,3,4-tetrahydrocarbazol e) on horizontal cell spinule formation, an indicator of the state of retinal adaptation. DH97 was capable of both counteracting dark-adaptive spinule degradation and inducing light-adaptive spinule formation at the beginning of the dark phase. Addition of dopamine receptor blockers opposed the action of DH97 on spinules, with SCH 23930, a D1 dopamine receptor antagonist, being more effective than the D2 receptor antagonist sulpiride. DH97 induced a twofold increase in dopamine release. We conclude that melatonin acts as a dark signal within the teleost retina by inhibiting the dopaminergic system. In accordance with this, both enantiomers of AMMTC prevented light-induced spinule formation, and reduced dopamine release to below dark-adaptive baseline levels. We suggest that the suppression of spinule formation by AMMTC may be due to either a direct inhibitory interaction between the melatonin agonist and horizontal cell dopamine D1 receptors, or an inhibitory effect on the activity of the dopamine-releasing interplexiform cells.

Adaptation, Ocular↗
PubMed2000

Comparison of C-arm CT fluoroscopy and conventional fluoroscopy for percutaneous biliary drainage procedures.

PURPOSE: To conduct a prospective randomized evaluation of C-arm computed tomography (CT) fluoroscopy for external biliary drainage procedures in comparison with conventional fluoroscopic guidance to reduce the number of transhepatic punctures as a primary endpoint. MATERIALS AND METHODS: In 18 patients with biliary obstructions, 20 external percutaneous biliary drainage procedures were prospectively performed with use of either C-arm CT fluoroscopy or conventional fluoroscopy alone. The number of hepatic punctures, procedure time, and fluoroscopy time, were analyzed separately for both methods. RESULTS: C-arm CT fluoroscopy resulted in a reduced number of transhepatic punctures, with decreased procedure and fluoroscopy times (P < .05; t test). When compared with conventional external biliary drainage procedures, a mean of 1.8+/-1 versus 4.8+/-2.8 hepatic punctures at a fluoroscopy time of 3.4+/-1.5 versus 11.4+/-7.4 minutes was required for C-arm CT fluoroscopy, while procedure times were 11+/-3.6 versus 16.2+/-9.3 minutes. CONCLUSIONS: C-arm CT fluoroscopy is associated with decreased procedure and fluoroscopy times, while fewer transhepatic punctures are required to establish external biliary drainage.

Adolescent↗
PubMed2000

Mid-term follow-up after percutaneous hydrodynamic thrombectomy in lower limb ischemia: initial experience with two-dimensional MR imaging and three-dimensional MR angiography.

PURPOSE: To assess noninvasively mid-term patency, reocclusion, and mid-term changes of the arterial wall after percutaneous hydrodynamic thrombectomy in patients with acute lower limb ischemia using magnetic resonance (MR) imaging/MR angiography (MRA). MATERIALS AND METHODS: Arterial wall and luminal changes were evaluated in 16 patients (10 men, six women; mean age, 70 years), with a minimum follow-up of 12 months after percutaneous thrombectomy with a hydrodynamic catheter for acute lower limb ischemia (embolic, n = 5; thrombotic, n = 11). Adjunctive PTA was performed in 44%. The mean follow-up was 23 months +/- 7.6 (range, 12-33 months). MR imaging and MRA were performed on a 1.0 T system using an extremity coil and two-dimensional (2D) time-of-flight, turbo spin echo, 2D gradient echo, and contrast enhanced three-dimensional (3D) gradient echo sequences. RESULTS: In one patient, a complete reocclusion was noted and, in two patients, a hemodynamically insignificant restenosis (< or = 50%) was identified with MR imaging. This was in accordance with color flow duplex sonography, physical examination, ankle/brachial index measurements, and the treadmill test. The MR morphometry documented an increase of the entire vessel area from 48.9 mm2 +/- 3.3 (control segments) to 55.5 mm2 +/- 2.8 at the treated segments (+13.3%; P < .05). The vessel wall area increased from 31.7 mm2 +/- 1.8 to 39.4 mm2 +/- 2.3 (+24.4%; P < .05). The mean area stenosis grade was 12%. CONCLUSION: MR imaging with use of morphometric analysis is a possible tool to noninvasively determine the mid-term patency and restenosis/reocclusion and remodeling process after percutaneous thrombectomy and other interventional procedures.

Aged↗
PubMed2000

Epstein-Barr virus-associated post-transplant lymphoproliferative disease after bone marrow transplantation mimicking graft-versus-host disease.

In contrast to solid organ transplantation (Tx), the incidence of post-transplant lymphoproliferative disease (PTLD) after hematopoietic stem cell Tx (HSCT) is generally low. This risk, however, is significantly elevated in patients receiving human leukocyte antigen (HLA) mis-matched or T-cell-depleted grafts, or after treatment for severe graft-versus-host disease (GvHD). An 18-yr-old patient with positive Epstein-Barr virus (EBV) serology received a fully matched, unmanipulated bone marrow graft from an unrelated EBV-positive donor for treatment of acute myeloid leukemia (AML) in second complete remission. GvHD prophylaxis was performed with cyclosporin A (CsA) and a short course of methotrexate. Four months after Tx, the patient developed ulcerative tonsillitis that was unresponsive to antibiotic treatment. Diarrhea appearing simultaneously was interpreted as gastrointestinal GvHD and steroids were added to CsA. A few days later the patient was admitted to hospital because of generalized seizure and pneumonia. Despite reduction of immunosuppression, intensification of anti-viral treatment, and subsequent mechanical ventilation, the patient died of acute respiratory distress 6 days later. Autopsy demonstrated disseminated EBV-induced, multi-nodular lymphoma infiltration of the entire colon but no signs of GvHD. Moreover, both lungs, paratracheal lymph nodes, kidneys, thyroid gland, and liver were infiltrated with large B-cell non-Hodgkin's lymphomas. This case underlines the rapid and aggressive course of EBV-induced disseminated PTLD after HSCT, initially mimicking intestinal GvHD because of massive colonic lymphoma infiltration. Tissue biopsies should be performed early for establishing correct diagnosis, thus enabling specific therapy, e.g. infusion of donor leukocytes with cytotoxic T-lymphocytes.

Adolescent↗
PubMed2000

The primary and memory immune response to Epstein-Barr virus infection in vitro is characterized by a divergent production of IL-1beta/IL-6 and IL-10.

Reactivation of latent Epstein-Barr virus (EBV) infection is considered to exert substantial immunomodulating activities. Little is known about EBV's modulating activities on cytokine production upon primary, in contrast to reactivated, infection. Therefore, we investigated the cytokine production of latently infected EBV-positive (EBV-pos) adults upon in vitro EBV stimulation compared to nonimmune age-matched EBV-negative (EBV-neg) donors. Production of interleukin (IL)-1beta and IL-6 was strongly decreased in peripheral blood mononuclear cell (PBMC) cultures of EBV-pos adults; in contrast, IL-10 and IL-1 receptor antagonist exhibited significantly higher levels. As expected, interferon (IFN)-gamma production was almost exclusively observed in EBV-pos donors; it was accompanied by a significantly higher IL-12 synthesis. Experiments employing T cell-depleted PBMC showed similar cytokine levels between EBV-pos and EBV-neg individuals suggesting that reactivation of EBV-specific memory T cells was responsible for the divergent cytokine profiles. Production of viral IL-10 was excluded as a reason for higher IL-10 levels in EBV-pos individuals. In conclusion, our results do not appear to relate to any primary immunological differences between EBV-neg and EBV-pos adults, but show that the EBV-specific memory response to latent EBV infection is characterized by some anti-inflammatory effects. This might be of relevance upon reactivation of latent EBV infection in vivo and provides further evidence that EBV infection acts in an immunomodulating fashion.

Adult↗