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Biomedical subjects

J Wurm

Publications and source records attributed to J Wurm.

16 recordsLinked to original sources
PubMed2007

[First experiences with a new nickel-titanium piston with a shape memory feature].

BACKGROUND: The aim of this study was to describe a new stapes prosthesis with memory characteristics for wire crimping (SMart-Piston). PATIENTS AND METHODS: This technique was used in 15 patients (mean age 43.4 years; range 28-71) undergoing routine stapes surgery. SMart-Piston prostheses with a shaft diameter of 0.5 mm and length ranging from 4.25-4.5 mm were used. Heat induced wire crimping was performed by CO2 laser in five patients, and by bipolar diathermy forceps in ten patients. In 15 patients, postoperative audiological testing was performed at an average 21.9 days and in another 10 again after 435 days following surgery. RESULTS: The median observed air-bone-gap (ABG) postoperatively was 8.7 dB+/-7.7 dB. A total of 73% of all patients had an ABG of 10 dB or less, and all patients had less than 20 dB. In the ten patients controlled after 435 days, the ABG was 4.4 dB+/-2.4 dB. It was lower than 10 dB in all individuals. DISCUSSION: A critical point in every stapes surgery, the prosthesis fixation to the incus, is greatly facilitated by this novel technique. Long-term results in a larger group of patients are pending.

Adult↗
PubMed2005

[Development of an active robot system for multi-modal paranasal sinus surgery].

BACKGROUND: Severe complications in endoscopic paranasal sinus surgery are rare, however, when they occur they are often fatal. Injuries to the optic nerve or the internal carotid artery mostly occur after penetration of the sphenoid sinus' anterior wall. METHODS: We present the robot system "A 73" with its newly designed 4-canal-microendoscope and special instruments that meets the demands of endoscopic paranasal sinus surgery. A fully automated perforation of the sphenoid sinus' anterior wall was performed in five cadaveric specimens. RESULTS: The sphenoid sinus' anterior wall could be perforated without damaging the surrounding structures in all cases. Subsequently, the approach was enlarged to the desired diameter using telemanipulation mode. The analysis of both the transformation error and intraopertive accuracy showed values in the submillimeter range. CONCLUSIONS: Using a newly developed robotic system, a fully automated perforation of the sphenoid sinus' anterior wall was performed precisely and reproducibly. This approach can be enlarged in a telemanipulation mode.

Cadaver↗
PubMed2005

[Endonasal removal of a large recurrent craniopharyngioma using intraoperative navigation].

In recent years computer-navigation systems have been commonly used in the field of otorhinolaryngology. Taking its limitations and possible failures into account, this technology is considered reasonable and helpful in routine paranasal sinus surgery, particularly in revision cases and complex approaches to the lateral skull base. We report on a patient with a large recurrent craniopharyngioma, and show that the use of intraoperative navigation might even be necessary to accomplish the desired postoperative outcome in certain cases. Future developments will demonstrate whether computer assisted surgery can extend the indications for operative procedures in complex anatomical regions.

Child↗
PubMed2005

An automated robotic approach with redundant navigation for minimal invasive extended transsphenoidal skull base surgery.

BACKGROUND: The aim of this work was to determine the feasibility of a robotic-assisted and fully automated approach to the sphenoid sinus. An image-guided robotic system was designed to address potential human errors in performing transsphenoidal sinus surgery by combining the reproducible accuracy of a robotic system with standard computer navigation. METHODS: A six-degrees of freedom robotic assistance system and an opto-electrical navigation system were combined for image-guided assistance with redundantly controlled robotics. Newly designed endoscopic instruments for robotic surgery have been developed and are described. Telemanipulatory, as well as fully automated procedures, were tested on cadaveric heads as part of a preclinical trial. RESULTS: A fully automated sphenoidotomy as well as a telemanipulatory sphenoidectomy were performed successfully on cadaveric heads. Intraoperative performance, accuracy assessment studies, as well as possible sources of stereotactic offsets are described. The mean measured robotic reproducibility accuracy was 0.056 mm (range: 0.02 - 0.14 mm) and the mean overall navigated robotic accuracy, including all transformation and registration errors was 1.53 mm (range: 1.13 - 1.89 mm) respectively. CONCLUSION: A system for robot-guided surgery in combination with redundant navigational control was developed. It allows highly accurate maneuvers, performed either in a telemanipulation mode as master-slave system or in a fully automated fashion. A sphenoidectomy on cadaveric heads was performed in both telemanipulation and fully automated modes. The overall intraoperative accuracy was in the range of the resolution of the CT images and stereotactic offsets were caused mainly due to deflections of the endoscopic operating instrument.

Cadaver↗
PubMed2004

[Complications with inflammatory diseases of the nasal sinuses].

The close localization of the paranasal sinuses both to the brain and the orbit can even today lead to severe and potentially lethal complications in patients with sinusitis. These incidents are rare, however, they should be duly diagnosed and treated since fatal outcome is described in 5-10% of cases. Current diagnosis and therapy for acute inflammatory complications and mucoceles of paranasal sinuses are presented in this article.

Eye Infections↗
PubMed2001

[Eicosanoid metabolism in peripheral blood cells in patients with cystic fibrosis].

BACKGROUND: The autosomal recessive inherited cystic fibrosis is the most common genetic disorder in white patients. Disturbances in the eicosanoid metabolism seem to play an important role in the pathogenesis of the disease. The present study shows examinations on the release of prostaglandin E2 (PGE2) and peptide leukotrienes (pLT) in peripheral blood cells. PATIENTS AND METHODS: In this respect heparinised blood samples of 10 cc were obtained from 25 patients with cystic fibrosis. The peripheral blood cells were separated from the remaining blood components. PGE2 and pLT were measured by a particularly developed sensitive enzyme immunoassay with specific monoclonal antibodies. Both the basal release of the metabolites and the concentrations after stimulation with arachidonic acid (AA) were explored. The control group consisted of 25 healthy individuals. RESULTS: A distinct elevation in the basal release of pLT compared to the control group was noticed. Further stimulation with AA could only be achieved to a remarkably smaller extent. In contrast to these findings no elevation of the basal release of PGE2 and no stimulative effect of AA could be detected. In general we observed a distinct shift in the eicosanoid metabolism in favour of pLT and their proinflammatory effects. CONCLUSIONS: The increased synthesis of pLT in patients with cystic fibrosis seems to play an important role in the pathogenesis of the disease. Future studies will have to proof, if we can achieve any improvement in the clinical courses in patients with cystic fibrosis using leukotriene receptor antagonists or 5-lipoxygenase inhibitors.

Adolescent↗
PubMed2000

Time-resolved fluorescence imaging of slab gels for lifetime base-calling in DNA sequencing applications.

A compact time-resolved near-IR fluorescence imager was constructed to obtain lifetime and intensity images of DNA sequencing slab gels. The scanner consisted of a microscope body with f/1.2 relay optics onto which was mounted a pulsed diode laser (repetition rate 80 MHz, lasing wavelength 680 nm, average power 5 mW), filtering optics, and a large photoactive area (diameter 500 microns) single-photon avalanche diode that was actively quenched to provide a large dynamic operating range. The time-resolved data were processed using electronics configured in a conventional time-correlated single-photon-counting format with all of the counting hardware situated on a PC card resident on the computer bus. The microscope head produced a timing response of 450 ps (fwhm) in a scanning mode, allowing the measurement of subnano-second lifetimes. The time-resolved microscope head was placed in an automated DNA sequencer and translated across a 21-cm-wide gel plate in approximately 6 s (scan rate 3.5 cm/s) with an accumulation time per pixel of 10 ms. The sampling frequency was 0.17 Hz (duty cycle 0.0017), sufficient to prevent signal aliasing during the electrophoresis separation. Software (written in Visual Basic) allowed acquisition of both the intensity image and lifetime analysis of DNA bands migrating through the gel in real time. Using a dual-labeling (IRD700 and Cy5.5 labeling dyes)/two-lane sequencing strategy, we successfully read 670 bases of a control M13mp18 ssDNA template using lifetime identification. Comparison of the reconstructed sequence with the known sequence of the phage indicated the number of miscalls was only 2, producing an error rate of approximately 0.3% (identification accuracy 99.7%). The lifetimes were calculated using maximum likelihood estimators and allowed on-line determinations with high precision, even when short integration times were used to construct the decay profiles. Comparison of the lifetime base calling to a single-dye/four-lane sequencing strategy indicated similar results in terms of miscalls, but reduced insertion and deletion errors using lifetime identification methods, improving the overall read accuracy.

DNA↗
PubMed2000

[Ligature of the carotid arteries performed prophylactically or as an emergency procedure in patients with malignant tumours of the head and neck].

Life threatening hemorrhage in patients with malignant tumours of the head and neck area are often, as a result of tumour infiltration, postoperative anatomical changes, infection and radiological necrosis, difficult to control. One option for prophylaxis and treatment is the ligature of the external (ECA) or common carotid artery (CCA) and superior thyroid artery (STA). 52 patients were examined in a retrospective study to determine both the hazards and the therapeutic use of the procedure. The external carotid artery (ECA) was ligated prophylactically during the operative procedure of tumour resection and neck dissection in 25 patients. In 27 cases closure of the ECA, CCA or ECA and STA was carried out as an emergency procedure for acute hemorrhage following completed primary treatment (operation, primary or postoperative radiation or radiochemotherapy). There was no postoperative hemorrhage after prophylactic ligature of the ECA. One patient with multiple cardiovascular diseases suffered from an ipsilateral cerebral infarction 1 year after operation. In 6 of 9 patients and in all 3 patients, in whom ligature of the CCA or ECA and STA respectively was carried out as an emergency procedure, severe neurological complications up to an apallic syndrome occurred. The number of deaths due to acute hemorrhage was considerably smaller among those patients with prophylactic ligature of the ECA performed during operative procedure of tumor resection and neck dissection. In addition there were much less unfavourable courses in the sequence of prophylactic closure of the ECA than observed after ligating the CCA or ECA and STA in an emergency situation.

Brain Ischemia↗
PubMed1997

Ectopic respiratory epithelium associated with multiple malformations.

We report a patient with unique cutaneous plaques of ectopic respiratory epithelium. The epithelium was located superficially as raised erythematous plaques on the right lateral surface of the neck with some viscous secretion. Underlying branchial cysts or sinuses were excluded. The occurrence of ectopic respiratory epithelium was associated with congenital deafness and a hare-lip in our patient, suggesting multiple malformation during early embryonic development.

Abnormalities, Multiple↗
PubMed1994

Australian pharmaceutical industry observed.

Multinationals are investing increasingly in local operations, with indigenous rather than expatriate managements. Scientific jobs are mainly filled by Australian graduates, many with overseas experience.

Australia↗
PubMed1992

[Schoenlein-Henoch syndrome with abdominal manifestations without skin involvement].

The etiology of Schoenlein-Henoch' Syndrome has not yet been fully clarified [10, 15]. An allergically toxic genesis is under discussion [8, 19]. The classical combination of symptoms consists of urticariel efflorescences, bleeding of skin and lining tissue and arthralgies [8, 19]. Involvement of kidneys and abdomen may occur [8, 19]. Our case report concerns exclusively an abdominal form with colics, vomiting and diarrhea [10, 18, 16]. Chemical tests reveal a reduction of factor XIII [1, 5, 21]. There is no involvement of kidneys, skin or joints. With reference to literature and this particular case, etiology, diagnosis and therapy are dealt with.

Child↗
PubMed1982

[Use of the ROC method in problems of image quality and quality control in mammography].

The ROC method is being used increasingly in radiology for the purpose of checking image quality. A phantom has been developed for use in mammography, which takes account of the tissues of the breast and of abnormal changes. In order to compare image quality, various films and film-screen systems were employed. The effect of slice-thickness, focal spot size and radiation scatter on image quality has been examined. The suitability of the method for quality control has been tested on a small sample. In addition, certain important parameters of the radiographic technique have been determined by physical measurements. Certain methodological difficulties must be considered, eg. the problem of statistical significance. It has been shown, however, that film-screen systems can approach the image quality of screenless films and require a lower dose of x-rays. For larger slice thickness, the use of a grid produces significantly better results than film without screens alone. The findings of the quality control show that it is important to check image quality by means of physical measurements. The ROC method has proved less valuable in this respect.

Female↗
PubMed1979

Genetics of type II glycogenosis: assignment of the human gene for acid alpha-glucosidase to chromosome 17.

We have studied somatic cell hybrids between thymidine kinase (EC 2.7.1.75) deficient mouse cells and human diploid fibroblasts for the expression of human acid alpha-glucosidase (EC 3.2.1.20). A deficiency in this enzyme is associated with the type II glycogenosis or Pompe disease. All 30 somatic cell hybrids selected in hypoxanthine/aminopterin/thymidine medium expressed human acid alpha-glucosidase and galactokinase (EC 2.7.1.6) and retained human chromosome 17; counterselection of the same hybrids in medium containing 5-bromodeoxyuridine resulted in the growth of hybrids that concordantly lost the expression of human acid alpha-glucosidase and galactokinase as well as human chromosome 17. Hybrids between thymidine kinase-deficient mouse cells and fibroblasts from a patient with Pompe disease that contained human chromosome 17 were found not to express human acid alpha-glucosidase. Because we have already shown that hybrids between mouse peritoneal macrophages and GM54VA simian virus 40-transformed human cells selectively retain human chromosome 17 and lose all other human chromosomes, we tested 13 independent mouse macrophage x GM54VA hybrid clones, including two that retained human chromosome 17 and no other human chromosomes, for the expression of human acid alpha-glucosidase and galactokinase. All 13 hybrid clones were found to express these human enzymes. Thus, we conclude that the gene coding for human acid alpha-glucosidase is located on human chromosome 17.

Animals↗