Biomedical subjects

J Maurer

Publications and source records attributed to J Maurer.

At least 19 recordsLinked to original sources

PubMed2001

[The Interesting Case No. 42. Differential diagnosis of epistaxis].

Epistaxis is a symptom and one of the most frequent medical emergencies. In most cases haemorrhages concern the anterior parts of the septum, in particular the Locus Kiesselbachi. Thus they are harmless and therapy is easy to handle. We report a case of a 55-year-old lady with relapsing epistaxis due to a pseudoaneurysm after surgery of a meningioma of the sphenoid bone. This type of epistaxis is rare and may culminate into a life-threatening event. The case demonstrates the importance of an exact differential diagnostic evaluation by use of modern imaging techniques for severe and life-threatening symptomatic nose-bleeding.

Aneurysm, False↗

PubMed2001

[Improved tumor site and contrast resolution in ultrasound diagnosis by using harmonic frequencies].

BACKGROUND: The aim of new techniques in head and neck sonography is to increase the sensitivity and the specificity of the examination. With tissue harmonic imaging (THI) and contrast harmonic imaging (CHI) new techniques are available which allow increased contrast and resolution in head and neck sonography as well as a better detection of small blood vessels. METHODS: We studied whether these techniques improve sonographic detection of head and neck lymph nodes and primary tumours of the upper aerodigestive tract. RESULTS: The results indicate that THI allows a better detection of cervical lymph nodes. Furthermore, intranodal structures and the borders of the lymph node can be better detected. Using CHI, typical patterns of vascularization can be seen, allowing a better interpretation of the node's tumour status. Primary tumours can be detected sufficiently well using conventional B-scan techniques although they are easier to detect with THI. Using CHI, many tumour vessels can be detected, but this does not increase the sensitivity of the sonographic examination. CONCLUSION: THI and CHI may increase the specificity of sonographic diagnostics of cervical lymph nodes but show no clinical benefit regarding the diagnostics of primary tumours of the upper aerodigestive tract.

Contrast Media↗

PubMed2001

The expression of cathepsins in osteoclast-like giant cells of an anaplastic thyroid carcinoma with tracheal perforation.

Anaplastic carcinoma of the thyroid gland (ACT) is a rapidly growing neoplasm with a very poor prognosis. In this study, we examined an ACT with osteoclast-like giant cells expressing matrix--degrading cysteine proteinases and their endogeneous inhibitor cystatin C. Bronchoscopic evaluation of a 50-year-old man suffering from hoarseness, dysphagia, and dyspnea revealed an irregular tumor mass infiltrating into the trachea and the cricothyroid ligament region. On histological examination, a necrotizing undifferentiated anaplastic carcinoma with osteoclast-like giant cells was detected. An immunohistochemical study of the tumor tissue was performed using a panel of 15 antibodies, including double labeling techniques. Most of the osteoclast-like multinucleated giant cells (MGC) expressed CD68 and cathepsin K. Colocalization of cathepsin B and its endogenous inhibitor cystatin C occurred in the majority of MGC. Mononuclear cells (MC) were positive for cathepsin B, cystatin C, and CD 68, but only faintly for cathepsin K. Expression of cathepsins B and K in the MGC of the ACT might contribute to the invasive behavior of this tumor, thus promoting metastatic ability and destruction of the cartilagenous trachea.

Biomarkers, Tumor↗

PubMed2001

Infection with Burkholderia cepacia in cystic fibrosis: outcome following lung transplantation.

As a result of concern over excessive mortality after lung transplantation, many transplant programs refuse to accept cystic fibrosis (CF) patients infected with Burkholderia cepacia. As a significant proportion of patients with CF in our community are infected with this organism, we have continued to provide lung transplantation as an option. A retrospective review was conducted of medical records of all patients with CF transplanted between March 1988 and September 1996. Fifty-six transplant procedures were performed in 53 recipients with CF between March 1988 and September 1996. Twenty-eight had B. cepacia isolated pretransplant and 25 remaining positive post-transplant. Of the 53 recipients, 19 have died (15 of 28 [54%] B. cepacia positive and 4 of 25 [16%] B. cepacia negative). B. cepacia was responsible for or involved in 14 deaths. Nine of the deaths occurred in the first 3 mo post-transplantation. One-year survival was 67% for B. cepacia positive patients and 92% for B. cepacia negative patients. Recent modifications in antimicrobial and immunosuppressive therapy since 1995 have resulted in no deaths early post-transplant in the last five patients transplanted. We conclude that early mortality in patients with CF infected with B. cepacia is significantly higher than in those not infected with B. cepacia. Modifications in post-transplant medical therapy may improve outcome.

Adult↗

PubMed2001

Complete form of X-linked congenital stationary night blindness: refined mapping and evidence of genetic homogeneity.

A number of distinct, partly non-overlapping genetic loci have been reported for the complete type of X-linked congenital stationary night blindness (CSNB1), suggesting genetic heterogeneity. In order to refine the localization of the CSNB1 gene and to demonstrate genetic homogeneity, linkage analysis was performed in two large CSNB1 families. Clinical features consistent with the diagnosis of CSNB1 were documented in five patients from a German seven-generation kindred by full ophthalmological examination including psychophysical and electroretinographical testing. Haplotype analysis in 30 members of the large German family was performed with 38 polymorphic markers predominantly covering the critical region. Linkage analyses defined a locus for CSNB1 with flanking markers DXS8042 and DXS228, refining the interval to 2.5 cM in Xp11.4. In addition, two-point linkage analysis was carried out using the MLINK computer program. In agreement with meiotic breakpoints, lod scores of 3.0 and greater were obtained for markers located to the proximal site of the former 5 cM CSNB consensus interval. A large Dutch CSNB1 family was re-evaluated with markers from the Xp11.4 region, and supports the CSNB1 minimal interval found in the German family. Together with previous results from three unrelated families from Sweden, Sardinia and Great Britain, our results provide evidence of genetic homogeneity in the disorder. Subsequent mutation analyses in CSNB1 patients revealed no pathogenic sequence alterations in DFFRX and CASK genes, but retain candidates for other diseases mapping to that region.

Calcium-Calmodulin-Dependent Protein Kinases↗

PubMed2000

Increased alveolar macrophage nuclear factor-kappa B activation and macrophage inhibitory protein-1alpha levels in lung transplant patients.

BACKGROUND: Lung transplantation is increasingly used as the treatment for many end-stage pulmonary diseases. A major cause of morbidity and mortality in patients who undergo lung transplantation is rejection of the allograft. Proinflammatory macrophage-derived cytokines may sustain and/or enhance the immunological response to lung allograft antigens. Nuclear factor-kappa B (NF-kappaB) is a transcription factor that regulates the production of many of these cytokines and growth factors in alveolar macrophages (AMs). The aim of our study was to evaluate the activation of NF-kappaB in AMs and the levels of one of the proinflammatory cytokines whose production it controls, macrophage inhibitory protein-1alpha (MIP-1alpha), in AMs from transplanted lungs compared to those from healthy controls. METHODS: Twenty-eight (28) transplant recipients were included in the study. NFkappaB activation was evaluated by electrophoretic mobility shift assay of whole cell extracts and by immunohistochemical analysis on cytospin preparations. Concentrated bronchoalveolar lavage fluid was analyzed by enzyme-linked immunosorbent assay for MIP-1alpha levels. RESULTS: NF-kappaB was activated in alveolar macrophages from transplant patients as compared to healthy controls. MIP-1alpha levels in epithelial-lining fluid were elevated in transplant patients as compared to healthy controls. Increased MIP-1alpha levels correlated with viral infections in the transplant patients. Neither finding was found to correlate with acute rejection by transbronchial biopsy. CONCLUSIONS: These results demonstrate that NF-kappaB activation and MIP-1alpha levels are increased in transplanted lungs and may play a role in the inflammatory cytokine cascade that leads to the long-term tissue damage and allograft rejection in these patients.

Bronchoalveolar Lavage Fluid↗

PubMed2000

Immuno-electron microscopic localization of the alpha(1) and beta(1)-subunits of soluble guanylyl cyclase in the guinea pig organ of corti.

Guanylyl cyclases (GC) catalyze the formation of the intracellular signal molecule cyclic GMP from GTP. For some years it has been known that the heme-containing soluble guanylyl cyclase (sGC) is stimulated by NO and NO-containing compounds. The sGC enzyme consists of two subunits (alpha(1) and beta(1)). In the present study, the alpha(1) and beta(1)-subunits were identified in the guinea pig cochlea at the electron microscopic level using a post-embedding immuno-labeling procedure. Ultrathin sections of LR White embedded specimens were incubated with various concentrations of two rabbit polyclonal antibodies to the alpha(1)- and beta(1)-subunit, respectively. The immunoreactivity was visualized by a gold-labeled secondary antibody in an energy-filtering transmission electron microscope (EFTEM). Marked immunoreactivity for both antibodies was found in the inner and outer hair cells, with numerous gold particles at the border of the cuticular plates, associated with the cell nuclei or attached to electron-dense parts of the cytoplasm. In the pillar cells and apical Deiters cells, soluble guanylyl cyclase immunoreactivity was located at the rim of the cuticular plates and between the microtubuli bundles. Together with the recently identified nitric oxide synthase isoforms [Eur. Arch. Otorhinolaryngol. 254 (1997) 396; Eur. Arch. Otorhinolaryngol. 255 (1998) 483], the soluble guanylyl cyclase may be involved in signalling processes in the organ of Corti.

Animals↗

PubMed2000

[Vascular origin of cerebellopontine angle syndrome].

INTRODUCTION: The seventh and eighth cranial nerves course toward the internal auditory canal within the cerebellopontine angle. Lesions in this region are usually related to malfunctions of these cranial nerves. Although an acoustic schwannoma is one of the main etiologies of cerebellopontine angle pathology, various inflammatory processes and vascular anomalies even though rare must be considered. PATIENTS/METHODS: We describe 5 cases with vascular loops of the basilar or vertebral arteries as a possible cause for hearing loss, vertigo and pulsatile tinnitus. In two cases the vascular lesion was confirmed at surgery, in which a decompression procedure was performed. The work-up for each patient included an auditory test battery and electronystagmography. Imaging studies included MRI and angiography in two cases. RESULTS/CONCLUSIONS: Our experiences show that while the cerebellopontine angle syndrome is mostly caused by benign tumors an abnormal vascular loop has to be considered in any differential diagnosis.

Adult↗

PubMed2000

[Value of ultrasound in early diagnosis of renal cell carcinoma].

The importance of ultrasonography in early detection of renal cell carcinoma was analyzed for 1854 patients, who were operated from 1975 to 1997. The 5-year survival rate of all patients amounts to 75%, the 10- and 20-year survival rate was 68% and 64%. While from 1975 to 1986 tumor symptoms like hematuria (30%), abdominal pain (19%) and palpable mass (3%) lead to diagnosis of renal cell carcinoma in 56% of all cases, there were only 26% from 1987 to 1997. 83% of asymptomatical tumors from 1987 to 1997 were accidentally detected by means of ultrasonography in a kidney independent examination. These tumors are significantly smaller (5.5 cm) than the tumors of symptomatical patients (7.8 cm) and show often a significantly lower local tumor stage, a better tumor grade, frequently lymph nodes, which are free of tumor infiltration and more rarely distant metastasis. The 5-year survival rate of patients with incidental tumors, detected by ultrasonography (82%) was significantly better (log rank < 0.001) in comparison with the symptomatical patients (72%). These results verify 1. The effectivity of ultrasonography in early diagnosis of renal cell carcinoma and 2. The advantage of survival on patients with early tumor detection. That's why asymptomatic patients, who selected under risk factors should be examinated by ultrasonography consistently too.

Adolescent↗

PubMed2000

Virtual endoscopy of the inner ear and the auditory canal.

To assess the role of virtual endoscopy (VE) in the examination of intracisternal structures and of the inner ear, we studied the anatomy of the labyrinth and internal auditory canal using the original CT slices and VE on the unaffected side in three female and three male patients, age range 3-46 years, with contralateral retrocochlear hearing loss. We also examined seven patients with different pathological findings. VE was performed using an advanced postprocessing program with high-resolution 3D data sets of CT (1-1.5 mm thickness, pitch 1.25) and MRI-CISS-3D (constructive interference in steady state) images of the basal cisterns (1.5 T, slice thickness 0.7-1 mm). VE provides an endoscopic-like view from a given point within the basal cisterns of vessels and nerves (on MRI) or of the structures of the inner ear (on CT). The complex anatomy and pathological changes in the inner ear can be faithfully shown. The main advantage is not basic diagnostic information but demonstration of topographically complex situations, such as the canalicular system of the inner ear, for discussion, preoperative planning and teaching.

Adolescent↗

PubMed2000

Possible roles of nitric oxide in the physiology and pathophysiology of the guinea pig cochlea.

Two nitric oxide synthase isoforms (NOS-I and NOS-III) are present in the mammalian cochlea, and many regulatory functions of the inner ear could be mediated by NO. In this study, cochlear potentials and immunohistochemical measures were analyzed by changing the concentration of NO in the guinea pig during intracochlear and intravenous application of an NOS inhibitor and an NO donor. In anesthetized guinea pigs the NOS inhibitor NG-nitro-L-arginine-methylester (L-NAME) was applied by intracochlear perfusion or intravenously. The cochlear potentials and blood pressure were measured during and after the application. Cochleae were removed and prepared for morphological and immunohistochemical examinations by light and electron microscopy. The same series of experiments was performed with the NO donor S-nitroso-N-acetyl-penicillamine (SNAP). Cochlear potentials were not altered during intracochlear perfusion or intravenous application of L-NAME or SNAP. With intravenous application of the substances, significant alterations in the systemic blood pressure were seen. No morphological alterations were noted but in the immunohistochemical investigations significant changes were detected by electron microscopy. Several possible functions of NO in the inner and outer hair cells, stria vascularis and ganglion cells are discussed. Our results suggest that NO has a major effect on the physiology of the inner and outer hair cells.

Animals↗

PubMed2000

Tongue-base suspension with a soft tissue-to-bone anchor for obstructive sleep apnea: preliminary clinical results of a new minimally invasive technique.

The Repose system is a new minimally invasive technique for tongue-base suspension in the treatment of sleep-disordered breathing caused by tongue-base collapse. It involves the insertion of a titanium miniscrew with attached suture into the anterior intraoral mandible and passing the suture through the tongue base. The procedure was performed in 16 patients with sleep-disordered breathing. Fourteen patients reported an improvement in daytime sleepiness, and their bed partners reported an improvement in snoring. The mean respiratory distress index before surgery was 35. Two months after surgery, the mean respiratory distress index was 17, an improvement of 51.4% (P = 0.001, 2-tailed t test). These preliminary results show the initial efficacy and safety of this new surgical procedure.

Adult↗

PubMed2000

The complete form of X-linked congenital stationary night blindness is caused by mutations in a gene encoding a leucine-rich repeat protein.

X-linked congenital stationary night blindness (XLCSNB) is characterized by impaired scotopic vision with associated ocular symptoms such as myopia, hyperopia, nystagmus and reduced visual acuity. Genetic mapping in families with XLCSNB revealed two different loci on the proximal short arm of the X chromosome. These two genetic subtypes can be distinguished on the basis of electroretinogram (ERG) responses and psychophysical testing as a complete (CSNB1) and an incomplete (CSNB2) form. The CSNB1 locus has been mapped to a 5-cM linkage interval in Xp11.4 (refs 2,5-7). Here we construct and analyse a contig between the markers DXS993 and DXS228, leading to the identification of a new gene mutated in CSNB1 patients. It is partially deleted in 3 families and mutation analysis in a further 21 families detected another 13 different mutations. This gene, designated NYX, encodes a protein of 481 amino acids (nyctalopin) and is expressed at low levels in tissues including retina, brain, testis and muscle. The predicted polypeptide is a glycosylphosphatidylinositol (GPI)-anchored extracellular protein with 11 typical and 2 cysteine-rich, leucine-rich repeats (LRRs). This motif is important for protein-protein interactions and members of the LRR superfamily are involved in cell adhesion and axon guidance. Future functional analysis of nyctalopin might therefore give insight into the fine-regulation of cell-cell contacts in the retina.

Amino Acid Motifs↗

PubMed2000

Quality assurance in RT-PCR-based BCR/ABL diagnostics--results of an interlaboratory test and a standardization approach.

Here we describe the results of an interlaboratory test for RT-PCR-based BCR/ABL analysis. The test was organized in two parts. The number of participating laboratories in the first and second part was 27 and 20, respectively. In the first part samples containing various concentrations of plasmids with the ela2, b2a2 or b3a2 BCR/ABL transcripts were analyzed by PCR. In the second part of the test, cell samples containing various concentrations of BCR/ABL-positive cells were analyzed by RT-PCR. Overall PCR sensitivity was sufficient in approximately 90% of the tests, but a significant number of false positive results were obtained. There were significant differences in sensitivity in the cell-based analysis between the various participants. The results are discussed, and proposals are made regarding the choice of primers, controls, conditions for RNA extraction and reverse transcription.

Base Sequence↗

PubMed2000

Autodisplay: functional display of active beta-lactamase on the surface of Escherichia coli by the AIDA-I autotransporter.

Members of the protein family of immunoglobulin A1 protease-like autotransporters comprise multidomain precursors consisting of a C-terminal autotransporter domain that promotes the translocation of N-terminally attached passenger domains across the cell envelopes of gram-negative bacteria. Several autotransporter domains have recently been shown to efficiently promote the export of heterologous passenger domains, opening up an effective tool for surface display of heterologous proteins. Here we report on the autotransporter domain of the Escherichia coli adhesin involved in diffuse adherence (AIDA-I), which was genetically fused to the C terminus of the periplasmic enzyme beta-lactamase, leading to efficient expression of the fusion protein in E. coli. The beta-lactamase moiety of the fusion protein was presented on the bacterial surface in a stable manner, and the surface-located beta-lactamase was shown to be enzymatically active. Enzymatic activity was completely removed by protease treatment, indicating that surface display of beta-lactamase was almost quantitative. The periplasmic domain of the outer membrane protein OmpA was not affected by externally added proteases, demonstrating that the outer membranes of E. coli cells expressing the beta-lactamase AIDA-I fusion protein remained physiologically intact.

Adhesins, Escherichia coli↗

PubMed2000

Progressive portopulmonary hypertension after liver transplantation treated with epoprostenol.

Portopulmonary hypertension (PPHTN) is an uncommon complication of advanced liver disease. Epoprostenol has been effective in the treatment of PPHTN and has been used as a bridge to orthotopic liver transplantation (OLT). The role of OLT in the reversal of PPHTN is unclear. We report a case of severe PPHTN (mean pulmonary artery pressure of 45 mm Hg) that progressed after OLT. Acute dosing with epoprostenol improved the pulmonary vascular resistance by 55% and the cardiac index by 134%. Hemodynamic and symptomatic improvements were maintained after 18 months of long-term treatment with epoprostenol. This is the first reported case of a successful favorable outcome after treatment for progressive PPHTN after OLT. Our case report complements previous reports by highlighting the potential effective use of epoprostenol as a definitive treatment for PPHTN.

Adult↗

PubMed2000

Detection of immunoglobulin heavy chain genes rearrangements in B-cell leukemias, lymphomas, multiple myelomas, monoclonal and polyclonal gammopathies.

Polymerase chain reaction (PCR) based assays were found to be a realistic alternative to Southern blot hybridization for the assessment of clonal immunoglobulin heavy chain gene rearrangements. However, a comparison of the different PCR based studies reveals considerable variation in experimental design and marked differences in the reported results. This study compared different single- and double-step PCR assays relying on various FR3, FR2, FR1 and JH based primers for the detection of B cell clonality in acute lymphoblastic leukemias (ALL), non-Hodgkin's-lymphoma (NHL), multiple myeloma (MM), monoclonal gammopathies of unknown significance (MGUS) and three polyclonal gammopathies (PG). The highest monoclonality rate was observed using seminested CDR-III region amplification. This method achieved a monoclonal product in 6 of 13 pro-B ALL 21 of 29 c-ALL, 7 of 8 pre-B-ALL, 18 of 21 B-ALL, 14 of 17 B-NHL (intermediate or high grade) with bone marrow involvement, 0 of 9 B-NHL without bone marrow involvement, 9 of 9 low grade B-NHL (immunocytoma and including chronic lymphocytic leucemia), 13 of 19 MM, 2 of 9 MGUS, and 0 of 3 PG. Additional monoclonality was detected with nested CDR I PCR in 1 pro-B-ALL, 1 c-ALL, and 2 MM. CDR III IgH PCR has been confirmed as an efficient method for determining clonality in B-cell neoplasias. Some additional monoclonal products can be seen with CDR I-based PCR. Detection of monoclonality depends on the maturation grade of the neoplastic B-cell population.

Bone Marrow Cells↗

PubMed2000

Exercise hemodynamic findings in patients with exertional dyspnea.

To determine whether upright bicycle exercise could provide useful information about disabling exertional dyspnea in the absence of severe abnormalities (as shown by traditional testing methods), we evaluated 13 such patients. There were 3 men and 10 women with a mean age of 49+/-15 (SD) years. We used pulmonary artery catheterization at rest and during upright bicycle exercise to evaluate these patients. All patients had normal left ventricular function except for 1, who had an ejection fraction of 45%. The mean duration to peak exercise was 9+/-6 minutes. Normal systolic pulmonary artery pressure was defined as 25+/-5 mmHg. Four patients had normal systolic pulmonary pressure, and 9 exhibited pulmonary hypertension with exercise. In those 9, the mean mixed pulmonary venous oxygen saturation at rest was 61%+/-9% and fell to 32%+/-9% at peak exercise. Six of the 9 patients also had some degree of resting pulmonary hypertension that worsened with exercise: their mean pulmonary artery systolic pressure at rest was 47+/-14 mmHg and rose to 75+/-25 mmHg at peak exertion (P = 0.01). The other 3 patients showed no pulmonary hypertension at rest; their mean pulmonary artery systolic pressure was 27+/-6 mmHg. However, this level rose to 53+/-4 mmHg at peak exertion (P = 0.04). In this pilot study of patients with dyspnea, 9 of 13 (69%) displayed marked pulmonary hypertension with exercise. The resting hemodynamic levels were normal in 3 (33%) of those with exercise pulmonary hypertension. We conclude that hemodynamic data from bicycle exercise tests can provide additional information regarding the mechanisms of exertional dyspnea.

Catheterization, Swan-Ganz↗