The LabTube - a novel microfluidic platform for assay automation in laboratory centrifuges.

Assay automation is the key for successful transformation of modern biotechnology into routine workflows. Yet, it requires considerable investment in processing devices and auxiliary infrastructure, which is not cost-efficient for laboratories with low or medium sample throughput or point-of-care testing. To close this gap, we present the LabTube platform, which is based on assay specific disposable cartridges for processing in laboratory centrifuges. LabTube cartridges comprise interfaces for sample loading and downstream applications and fluidic unit operations for release of prestored reagents, mixing, and solid phase extraction. Process control is achieved by a centrifugally-actuated ballpen mechanism. To demonstrate the workflow and functionality of the LabTube platform, we show two LabTube automated sample preparation assays from laboratory routines: DNA extractions from whole blood and purification of His-tagged proteins. Equal DNA and protein yields were observed compared to manual reference runs, while LabTube automation could significantly reduce the hands-on-time to one minute per extraction.

[Endonasal dacryocystorhinostomy with transillumination of the lacrimal sac: implementation and results]. / Die endonasale Dacryocystorhinostomie mit Transillumination des Tränensackes: Durchführung und Resultate.

PATIENTS: Since Mai 1991 we performed a total of 17 endonasal dacryocystorhinostomies under transillumination of the lacrimal sac on 15 patients with lacrimal obstruction aged 11 to 88 years. 11 patients with 12 operations were followed up between 40 and 393 days (mean of 5.6 months). RESULTS: In all cases the connection between the lacrimal sac and the nasal cavity remained functionally open. One patient developed a secondary canalicular stenosis which made silicon tubing necessary. CONCLUSIONS: We consider the operation an elegant and as far as our experience goes reliable method to recanalize the lacrimal drainage system avoiding a cutaneous incision. It is simplified by the transillumination of the lacrimal sac under videoendoscopic conditions.

[Fronto-basal fractures in the child]. / Frontobasale Frakturen beim Kind.

The particularities and the authors' management of frontobasal fractures in children are discussed on the basis of cases treated at the authors' department during the last five years. Fifteen children aged between four and 16 years (mean eight years) made up 14.5% of all frontobasal fractures. The causes of the injury were equally divided between falls from a height of at least 2 m and traffic accidents. All children except one were treated immediately after the accident. The exception was a child with an accident two and a half years before operation and two episodes of late onset meningitis. The diagnoses were mainly made with the help of high resolution computer-tomographies, which permitted a correct localization of the fractures site. The exact course of the fracture was recognized correctly in seven of eleven cases. Each case was managed in interdisciplinary fashion together with the neurosurgeon and the general surgeon. If nonoperative management was chosen, a computer-tomography about six weeks after the injury had to demonstrate the return to normal appearance of the paranasal sinus. If a dural tear was ascertained, a repair with a rhinosurgical approach was favored and, thereby, a definite closure was obtained in seven out of nine cases. One case was primarily managed by a combined rhino- and neurosurgical approach, while two cases were reoperated neurosurgically because of persistent cerebrospinal fluid leakage after the rhinosurgical repair. No other postoperative complications, such as meningitis or a third operation, were encountered. The authors believe that these favorable results were obtained because of individual management of each case by an interdisciplinary team working closely together.

[Frontobasal fractures in children]. / Frontobasale Frakturen im Kindesalter.

In 1987, four children between 5 and 13 years of age with severe frontobasal trauma and dural tears were treated operatively. A CSF rhinorrhea was manifest clinically in only two cases. In addition high-resolution computerised tomography was essential in diagnosis and planning of the operation. In each of the cases an intracranial pneumatocele indicating dural laceration was shown. The fractures were confirmed during surgery in: Case 1. The roof of the ethmoid sinus and the roof of the orbit. Case 2. Both the sphenoid sinuses. Case 3. The roof of the ethmoid sinus and the posterior wall of the frontal sinus. Case 4. The roof of the ethmoidal sinus and the posterior wall of the frontal sinus. The ontogenetically oldest part of the paranasal sinuses in the floor of the anterior cranial fossa forming the anterior part of the roof of the ethmoid bone is the site of predilection for fractures, even in children. The anterior cranial fossa was exposed in each case through a paranasal subfrontal access, in the first case combined with a frontal craniotomy by a neurosurgeon, because of the fracture of the roof of the orbit. In the second case the dural injury had to be closed at a second neurosurgical operation, because of a recurrence of the CSF leak. The third and fourth cases were treated by nasal surgery alone.

[Intensity of the vestibulo-ocular reflex as a response to thermal labyrinth stimulation with water and air. Comparative studies of the stimulus intensity in thermal vestibular assessment in healthy probands]. / Die Intensität des vestibulo-okulären Reflexes als Antwort auf die thermische Labyrinthreizung mit Wasser und Luft. Vergleichende Untersuchung zur Reizintensität bei der thermischen Vestibularisprüfung bei gesunden Probanden.

In 22 otoneurologically healthy subjects (44 ears) the response of the labyrinthine system to stimulation was studied for the method using water, standardized according to Mulch and Scherer (1980), and for our method of stimulation by air. The mean values of the speed of the slow phase and of the total amplitude of the vestibular nystagmus were significantly lower in case of air stimulation. If we consider each stimulus modality separately, the nystagmus parameters correlate significantly in the right-left comparison, and likewise the right predominant nystagmus with the left predominant nystagmus. However, on comparing the data measured for air stimulation and for water stimulation, no correlation could be established. The reason is thought to be an energetic one, since the method using air depends on heat capacity and heat transfer, whereas the method employing water depends on heat transfer only. Calculation shows that the energetic conditions of the method employing air are of the same order of magnitude as the roughly quantitative minimal rinse when filling the auditory meatus with water of moderate temperature. Hence, thermal stimulation of the labyrinthine system with air reacts very sensitively to changes in experimental conditions, so that all conditions must be strictly adhered to and standardised and the examination methods must be repeatable within narrow tolerance limits. On account of its low mean values and great susceptibility to variation, the method of air stimulation should be discouraged, especially in the assessment of patients who are suspected of suffering from a disease of the vestibulum auris.

[Duration and complications following grommet insertion in childhood]. / Verweildauer und Komplikationen nach Paukenröhrcheneinlage im Kindesalter.

We report 1000 insertions of ventilation tubes in 534 children for secretory otitis media (SOM) within a period of 6 years. In 77.5% of the cases, the air-bone gap was greater than 20 dB. The grommets are allowed to undergo spontaneous expulsion which happened in 319 ears, about 7 months after insertion. SOM recurred in 32.6% of the cases once, in 5.0% of the cases twice, and in 1.9% three times, requiring re-insertion of grommets. Recurrence appeared between 4 and 65 months after the first insertion. In three cases perforations of the tympanic membrane persisted and required tympanoplasty. Tympanometric examination and pure tone audiometry are necessary, in addition to pure tone audiometry to follow up successfully ventilated middle ears and to show recurrence as early as possible. Pre-existing but unsuspected sensorineural hearing loss was discovered in 10 cases. The deprivation of neural auditory pathways in early childhood and the possible retardation of speech development caused by SOM are mentioned. Normal hearing is the most important goal of therapy in children suffering from SOM, and insertion of ventilation tubes is the preferred method of achieving that goal safely. Adenoidectomy and treatment of upper airway infections are indispensable parts of the therapy of SOM. Regular follow up after insertion of grommets and even after their expulsion is necessary because of the high rate of late recurrence of SOM. Induction of cholesteatoma by grommets was not observed.

[Septum deviation and concomitant sinusitis]. / Septumdeviation und Begleitsinusitis.

It is generally assumed that there is a relation between nasal obstruction due to deformities of the nasal septum and disease of the paranasal sinuses. We investigated patients with septal deviation and rhinomanometrically determined nasal obstruction and checked the sinuses before septal surgery by radiography, ultrasonography, and endoscopy. The results of our investigation on 150 unselected patients during 1983 support the hypothesis. We found that non-invasive diagnostic methods, i.e. radiography and ultrasound were sufficiently reliable. Furthermore we found that more men are afflicted with deformities of the nasal septum than women. Nearly half of the number of patients needed therapy for the paranasal sinuses. Therefore preoperative diagnosis of sinusitis is essential before nasal septum surgery.

[The place of rhinomanometry in septum surgery]. / Zur Stellung der Rhinomanometrie in der Septumchirurgie.

On 141 patients the nasal ventilation was measured by anterior rhinomanometry the day before septal surgery according to Cottle. 71 patients could be controlled in mean 54 days after surgery. 59 rhinomanometric measurements could be compared concerning nasal ventilation before and after surgery. There was statistically significance for improvement of nasal ventilation as well as symmetry. The method of anterior rhinomanometry is well suited to document and compare the nasal function in septal surgery for clinical interests.

[Differential diagnostic reflections on sudden deafness: rupture of the round window membrane]. / Differentialdiagnostische Uberlegungen zum Hörsturz: Ruptur der runden Fenstermembran.

The rupture of the round window membrane has been the origin of sudden deafness in two cases that are described in this presentation. We are able to verify the rupture of the round window membrane before surgery by using differential diagnostic criteria, though there existed only relative slight hearing losses of about 40 dB. After surgery we found normal hearing in one case and a decreased hearing loss in the other. Vestibular symptoms have been leading to the diagnosis in both cases and the middle ear effusion in one case.