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Biomedical subjects

A Ernst

Publications and source records attributed to A Ernst.

At least 37 records · Page 2Linked to original sources

[Mode-of-action of manual medicine in the cervical spine].

Manual medicine aims at diagnosing and treating different disorders of the musculoskeletal system. It is a multidisciplinary approach with special emphasis on reversible disorders of the joints, muscles and ligaments. This treatment conception includes chirotherapy, physical therapy and drug treatment. The spine, an in particular the cervical spine, is treated primarily for joint disorders characterized by a variety of symptoms (e.g.headache, vertigo, dizziness, blurred vision). Manual medicine should be an integral part of modern clinical otolaryngology.

Cervical Vertebrae↗

[Tracheal ruptures in endotracheal intubation. Diagnosis and therapy].

BACKGROUND: Tracheal ruptures are most frequently the result of a blunt trauma to the thorax or of forced intubation. They represent a rare, but life-threatening complication that requires immediate help. METHODS: The resulting pneumothorax and the skin/mediastinal emphysema are the most prominent clinical signs. Injuries of the tracheobronchial tract should be diagnosed endoscopically and treated surgically immediately after the trauma. RESULTS: The present paper reports on three cases of tracheal ruptures after forced intubation which could be successfully managed by tracheostomy and subsequent reconstruction of the defects. The postoperative care of the patients is critically discussed.

Bronchoscopy↗

Differences between trunk sway characteristics on a foam support surface and on the Equitest ankle-sway-referenced support surface.

Clinicians have sought ways to increase trunk sway so that it is easily observed and a balance deficit more easily identified. One technique often used for this purpose is to reduce the efficacy of ankle proprioceptive inputs on sway. To achieve this reduction either a foam mat is used as an unstable support surface or the subject stands on a surface made unstable with servo-driven ankle-sway-referencing. The purpose of the current study was to investigate differences in trunk pitch and roll sway characteristics using these techniques. Trunk sway while standing quietly on two legs was measured in 25 normal subjects in the age range 20-35 years for three support-surface conditions. Each condition was tested twice for 20 s, once with eyes open and once with eyes closed. The three conditions were standing on a foam support surface, standing on a support surface with pitch (fore-aft) ankle-sway-referencing as used for the standard Sensory Organization Test (SOT) of the Neurocom Equitest System (SOT 4 and 5), and standing with roll (lateral) ankle-sway-referencing. The latter was achieved by having the subjects stand turned 90 degrees to the standard SOT position. Two angular velocity sensors mounted on a belt measured trunk sway in the pitch and roll directions. Trunk roll angle and angular velocity amplitudes for pitch sway-referencing were reduced compared to either the foam or roll sway-referencing conditions, but trunk pitch angle and angular velocities amplitudes were greater. For roll sway-referencing, the trunk roll angle was greater than for the other stimulus conditions. Analyses of the trunk sway velocity in the frequency domain indicated that ankle-sway-referencing in the pitch direction increased trunk pitch sway at 1 Hz and decreased trunk roll sway between 2 and 5 Hz compared to foam support frequency spectra. Roll ankle-sway-referencing decreased trunk roll between 2 and 4 Hz only. These results indicate that using a foam support surface provides multidirectional trunk sway with velocity content across all frequencies in the range 0.8-5.2 Hz. Roll ankle-sway-referencing, but not pitch ankle-sway-referencing, yields trunk sway with similar characteristics to those with foam. Pitch ankle-sway-referencing forces pitch trunk resonance to be around 1 Hz and yields very different trunk sway from that obtained with a foam support surface. Roll sway-referencing is an alternative means to test multidirectional control of sway. Clinically though, foam is simpler to use and provides a more difficult balance task for the patient.

Adult↗

Endobronchial ultrasound-guided transbronchial lung biopsy in solitary pulmonary nodules and peripheral lesions.

Transbronchial biopsy (TBBX) for peripheral lung lesions is usually performed with the help of fluoroscopy, but the yield varies widely. This feasibility study aimed to assess the ability of endobronchial ultrasound (EBUS) to provide imaging guidance for TBBX. In a prospective study, 50 consecutive patients referred for TBBX for peripheral lesions underwent fluoroscopy-guided and EBUS-guided TBBX in random order. Diagnostic yields were compared for both modalities and feasibility was assessed for EBUS. Diagnostic material was obtained in 80% of patients with EBUS and 76% of patients with fluoroscopy. There was a nonsignificant trend for EBUS to be better than fluoroscopy for lesions <3 cm in diameter. Four lesions could not be visualised with EBUS. There were no significant complications associated with the use of EBUS. Endobronchial ultrasound-guided transbronchial biopsy is feasible. It appears to be at least equivalent to fluoroscopy without the accompanying radiation exposure. Further large-scale studies are indicated to assess the possible role of endobronchial ultrasound as a potential imaging method of choice for the biopsy of peripheral lung lesions.

Adult↗

Endobronchial ultrasound in therapeutic bronchoscopy.

Endobronchial ultrasound (EBUS) has been introduced as an adjunct to diagnostic bronchoscopy as it allows evaluation of the submucosal and parabronchial structures. Its use in therapeutic bronchoscopy has not been assessed. A large observational study of the value of EBUS in therapeutic bronchoscopy is presented here. From January 1998-January 2001 all patients undergoing therapeutic bronchoscopy and EBUS were evaluated prospectively. Patient demographics, indication for bronchoscopy, interventional treatments used and changes in therapy as influenced by the use of EBUS were documented. A total 2,446 therapeutic bronchoscopies were performed. In 1,174 cases EBUS was used (29% mechanical tumour debridement, 20% airway stenting, 13% Neodymium:yttrium aluminium garnet (Nd:YAG) laser use, 23% argon plasma coagulation, 11% brachytherapy, 2% foreign body removal and 2% endoscopic abscess drainage). EBUS guided or changed therapy significantly in 43% of cases. Changes included adjustment of stent dimensions, termination of tumour debridement when nearing vessels, and referral for surgical interventions rather than endoscopic treatment. Complications associated with EBUS use were minimal. No patient undergoing EBUS guided tumour destruction experienced severe bleeding or fistula formation. In summary, endobronchial ultrasound was easily performed and changed or guided therapeutic decisions during therapeutic bronchoscopic procedures in a substantial number of cases. As this may result in better outcomes, it has become a standard adjunct in the authors practice.

Adult↗

Hydrogen peroxide inhibits gap junctional coupling and modulates intracellular free calcium in cochlear Hensen cells.

The double whole-cell patch-clamp configuration was applied to analyze gap junctional conductance (Gj) of isolated pairs of cochlear supporting Hensen cells of guinea pig under control conditions and in the presence of hydrogen peroxide (H2O2). Under control conditions, the dependence of Gj on transjunctional voltage (Vj) appeared to vary between different cell pairs with a maximum value of about 40 nS at Vj close to 0 mV. The voltage dependence and the maximum amplitude of Gj stayed constant for at least 2 hr. Addition of H2O2 to the bath at concentrations above 0.08 mm caused a significant decrease of Gj, but the membrane potential of about -30 mV was not affected. In parallel, intracellular free calcium ([Ca2+]i) was followed using fura-2. At 0.8 mm H2O2, a sustained increase of [Ca2+]i was observed, while 0.08 mm H2O2 evoked an oscillating-like behavior of [Ca2+]i. We propose that the H2O2-evoked inhibition of gap junctional coupling of Hensen cells is closely related to pathophysiological conditions such as noise- induced hearing loss, aminoglycoside-related ototoxicity and presbycusis, which are known to be associated with production of free radicals.

Animals↗

Fine structure of E. coli RNA polymerase-promoter interactions: alpha subunit binding to the UP element minor groove.

The alpha subunit of E. coli RNAP plays an important role in the recognition of many promoters by binding to the A+T-rich UP element, a DNA sequence located upstream of the recognition elements for the sigma subunit, the -35 and -10 hexamers. We examined DNA-RNAP interactions using high resolution interference and protection footprinting methods and using the minor groove-binding drug distamycin. Our results suggest that alpha interacts with bases in the DNA minor groove and with the DNA backbone along the minor groove, but that UP element major groove surfaces do not make a significant contribution to alpha binding. On the basis of these and previous results, we propose a model in which alpha contacts UP element DNA through amino acid residues located in a pair of helix-hairpin-helix motifs. Furthermore, our experiments extend existing information about recognition of the core promoter by sigma(70) by identifying functional groups in the major grooves of the -35 and -10 hexamers in which modifications interfere with RNAP binding. These studies greatly improve the resolution of our picture of the promoter-RNAP interaction.

Amino Acid Motifs↗

[Mesenchymal chondrosarcomas of the facial skull].

A 13-year-old girl suffered from a mesenchymal chondrosarcoma of the left maxilla. The therapeutic options and the prognosis for this disease are described with respect to the currently known 72 cases in the literature. Mesenchymal chondrosarcomas are rare tumors of the bone and soft tissue. The first clinical symptom is a painless swelling of the facial skull. They occur largely in the 2nd and 3rd decades of life, preferentially in males. Radiological criteria for the identification of this type of tumor include focal ossification areas which are accompanied by non-calcified regions. Complete surgical removal of the tumor is the therapy of choice. Pre- and postoperative chemotherapy can have a beneficial effect. The final outcome of the disease is difficult to evaluate since late complications (e.g., reoccurrence and/or metastases) appear even after 20 years and only a small number of cases have been reported. At present, the 5-year survival rate is reported to be 54-82% and the 10-year rate 28-56%.

Adolescent↗

Documentation in bronchology.

With the performance of more endoscopic procedures and newly developed diagnostic and therapeutic modalities, a wealth of information around the actual procedure is created. To date, accepted guidelines for standardized documentation are lacking. The authors present recommendations for minimal guidelines that may help to facilitate good documentation and also address future developments that will be possible with the help of computer-assisted approaches.

Bronchoscopy↗

CT fluoroscopy guidance for transbronchial needle aspiration: an experience in 35 patients.

OBJECTIVE: To demonstrate the usefulness of real-time guidance with CT fluoroscopy to improve the yield of transbronchial needle aspiration (TBNA). DESIGN: Prospective, observational. SETTING: A tertiary-care, university-affiliated medical center. METHODS: From December 1998 to April 2000, 35 patients underwent CT fluoroscopy-guided TBNA. Patients with subcarinal and precarinal lymph nodes were only included if a previous attempt was nondiagnostic, as the initial yield in this setting with conventional TBNA is high. TBNA was performed using standard technique in a CT-scan suite. Needle location was confirmed with fluoroscopy without IV contrast being used. Specimens were evaluated on-site for adequacy. RESULTS: The procedure had to be aborted in three patients before TBNA could be performed. Samples were obtained in 32 patients. Samples were nondiagnostic in four patients. Adequate tissue was obtained in 28 of 32 patients (87.5%). Twenty-two patients had a specific benign or malignant diagnosis made, and 6 patients had lymphocytes only on the specimen. In follow-up, only one of these six patients proved to have a malignancy. All procedures were performed within a regular interventional CT time slot of 1 h. No TBNA side effects were noted. CONCLUSION: TBNA under CT fluoroscopic guidance is easy to perform. The yield in all accessible lymph node stations is high.

Adult↗

Successful bronchoscopic placement of tracheobronchial stents without fluoroscopy.

BACKGROUND: Tracheobronchial stenting is performed increasingly often. Fluoroscopic control, which leads to significant radiation exposure for patients and staff, is recommended for the placement of metal stents. METHODS: All consecutive patients referred to two airway centers in need of airway stenting who received stents (Ultraflex; Boston Scientific, Natick, MA) underwent placement using endoscopic guidance only. All data were collected in an ongoing continuous database. RESULTS: One hundred stents were placed in 96 patients for central airway obstruction, and the data were reviewed. Stents were placed in all locations within the central airways for a variety of indications but mainly for malignant obstruction. No complications occurred, and all stents were placed satisfactorily. CONCLUSION: At centers with dedicated airway teams, Ultraflex stents can be quickly and safely inserted without the need for fluoroscopy. This saves radiation exposure to patients and to staff and may lead to a more cost-effective procedure.

Adult↗

Long-term outcome and lung cancer incidence in patients with hemoptysis of unknown origin.

STUDY OBJECTIVE: To provide current data on the long-term outcome and incidence of lung cancer in a large cohort of patients with hemoptysis of unknown origin. DESIGN: A retrospective chart review followed by a telephone interview for follow-up. SETTING: A university-affiliated tertiary referral center for pulmonary diseases. PATIENTS: Seven hundred twenty-two patients who presented with hemoptysis from January 1990 to December 1993. One hundred thirty-five patients were identified as having hemoptysis of unknown origin. RESULTS: One hundred thirty-five patients (19%) had hemoptysis of unknown origin; follow-up data were obtained in 115 patients, of whom 100 were still alive. The mean time of observation was 6.6 years after initial presentation. Lung cancer developed in 7 of 115 patients (6%) and was unresectable once detected; all of these patients were smokers > 40 years old, and malignancy developed within 3 years after first presentation. CONCLUSIONS: Hemoptysis of unknown origin is present in a minority of patients presenting with hemoptysis if evaluated at a referral center for pulmonary diseases. Lung cancer seems to be increasing in these patients compared to previous studies, and closer follow-up or additional testing may be indicated in the defined population at risk.

Adult↗

Regulation of lens rCx46-formed hemichannels by activation of protein kinase C, external Ca(2+) and protons.

Rodent lens connexin46 (rCx46) formed active voltage-dependent hemichannels when expressed in Xenopus oocytes. Time-dependent macroscopic currents were evoked upon depolarization. The observed two activation time constants were weakly voltage-dependent and in the order of hundreds of milliseconds and seconds, respectively. Occasionally, the macroscopic steady-state current and the corresponding current-voltage curve showed inactivation at high depolarizing voltages (>+50 mV). To account for the fast recovery from inactivation (<2 msec) favored by hyperpolarization, a four-state kinetic model (C(1)(closed) <--> C(2)(closed) <--> O(open) <--> I(inactivated)) is proposed. In the absence of inactivation, the macroscopic conductance decreased and inactivation became visible at voltages positive of +50 mV when the rCx46-expressing oocytes were treated with the protein-kinase-C-activators OAG or TPA, high external concentrations of Ca(2+) or H(+). However, the underlying mechanisms of OAG, H(+) or Ca(2+) action were different. While OAG did not alter the voltage-dependent activation of the rCx46-hemichannels, an increase in the external Ca(2+) or H(+) level shifted the voltage threshold for activation to more positive voltages. In contrast to Ca(2+), protons were not effective in the physiological concentration range. We propose that under physiological conditions only external Ca(2+) and intracellular PKC-dependent processes regulate rCx46 in the lens.

Animals↗

[Reconstruction of traumatic skull base defects with alloplastic, resorbable fleece].

BACKGROUND AND OBJECTIVE: Defects of the frontal skull base can be reconstructed with different types of material. Homologous material possibly involves the risk of infection and thus complicated wound healing. Therefore, alloplastic material seems to be an interesting alternative. PATIENTS/METHODS: In the present paper, we report on a series of 45 patients who underwent reconstruction of the anterior skull base. The defects were localized in different regions and had a maximum diameter of 10 cm2. Of the defects, 39 were closed via a sandwich technique and 12 via an onlay. The rhinosurgical approaches were aimed at closing the defects with Ethisorb, a resorbable collagen texture, and supporting the surgical field with a balloon catheter from below. Postoperative controls were performed after 6 weeks (endoscopy, determination of beta 2-transferrin) and 6 months (CT scans). RESULTS: All defect reconstructions were stable and tight, i.e., neither a CSF leakage nor a meningoencephalocele was found. The healing was completely normal and the endoscopic controls showed a regular mucosal lining over the defects. CONCLUSIONS: We conclude that Ethisorb is a useful alternative material in the treatment of frontal skull base defects.

Adolescent↗

The blue-colored linker polypeptide L55 is a fusion protein of phycobiliproteins in the cyanobacterium synechocystis sp. strain BO 8402.

The cyanobacterium Synechocystis sp. strain BO 8402, isolated from Lake Constance, lacks phycobilisomes but instead forms inclusion bodies containing remnants of phycobiliproteins. The inclusion bodies are surrounded by a proteinaceous capsule and contain alpha-phycocyanin and beta-phycocyanin, the rod linker polypeptide L35RPC and a novel blue-colored protein L55 with an apparent molecular mass of 55 kDa. An antibody raised against beta-phycocyanin showed a strong cross-reaction with L55. Mass spectrometry analysis of proteolytic peptides from L55 revealed mass identity to proteolytic peptides derived from L35RPC and beta-phycocyanin. However, analysis of the genome of strain BO 8402 revealed only one cpcBACE operon, encoding the apoproteins of beta-phycocyanin and alpha-phycocyanin, L35RPC and a subunit of the phycocyanin alpha subunit phycocyanobilin lyase, respectively. The gene structure, sequence and transcription of these genes were identical to that of a revertant strain, Synechocystis sp. strain BO 9201, which formed phycobilisomes and did not express L55. Based on these observations, we concluded that L55 did not derive from a particular gene or from a special form of mRNA-processing. We propose that L55 is formed by post-translational fusion of L35RPC and beta-phycocyanin. Cross-linking may stabilize the formation of the large paracrystalline phycocyanin aggregates unique to Synechocystis sp. strain BO 8402.

Amino Acid Sequence↗