Detection of tympanic membrane movement using film patch with integrated strain gauge, assessed by optical coherence tomography: experimental study.

OBJECTIVE: We report an ex vivo and in vivo experimental study of a device designed to measure tympanic membrane movement under normal and pathological conditions, assessed using optical coherence tomography. MATERIALS AND METHODS: We designed two types of flexible, round film patch with integrated strain gauge, to be attached to the tympanic membrane in order to measure tympanic membrane movement. Tympanic membrane attachment was assessed using optical coherence tomography. The devices were tested experimentally using an ex vivo model with varying middle-ear pressure. RESULTS: Optical coherence tomography reliably assessed attachment of the film patch to the tympanic membrane, before and after middle-ear pressure changes. Strain gauge voltage changes were directly proportional to middle-ear pressure recordings, for low pressure changes. Tympanic membrane perforations smaller than 2 mm could be sealed off with the film patch. CONCLUSION: Attachment of the film patch with integrated strain gauge to the tympanic membrane was not ideal. Nevertheless, the strain gauge was able to precisely detect small pressure changes within the middle ear, in this experimental model.

[Tensometry - development of a measurement technique of the tube function in a temporal bone model]. / Tensometrie - Entwicklung eines Langzeitmessverfahrens der Tubenfunktion am Felsenbeinpräparat.

OBJECTIVE: Middle ear pressure depends widely on the function of the eustachian tube. Tube dysfunction is often a trigger for middle ear diseases like chronic otitis media but also for barotrauma. Patients with impaired tubal function should not be exposed to situations with extreme pressure changes. Until today, there is no valid examining method for long-time measuring of the development of middle ear pressure. MATERIAL AND METHODS: The basic idea was to develop a thin flexible film with integrated strain gauges made of platinum and gold, which can be applied directly on the surface of the tympanic membrane. Using these, shifts or distensions of the tympanic membrane in a temporal bone model can be measured and documented. RESULTS: We were able to show that the measuring system was sensitive enough to register pressure variations in the middle ear volume of a temporal bone model. While using a full bridge design of the strain gauge resistors it could be shown that the measuring voltage of the strain gauges were in phase of the pressure measurement curve or according to the positioning in opposite phase. In single resistor mode the measurement were not so positioning depended. Measuring tympanic membrane movement in case of perforation was feasible. CONCLUSIONS: To improve the longtime stability of the strain gauge film the next development step will be to make a new design with Konstantan resistors (CU-Ni-Mn). After a testing period, longtime measurements in clinical studies will follow.

New arguments to explain the high infection rate in posttraumatic spleenless patients.

To get more information about the high infection rate in splenectomized adult patients 211 spleenless patients were investigated with regard to clinical and laboratory data and compared to healthy blood donors. The results show that the infection rate is markedly increased to 30%. Splenectomized patients have decreased IgG levels which is due to diminished IgG1 and IgG4. Whereas IgA, complement factors C3, C4, and transferrin are not changed in patients without spleen, fibronectin and IgM are significantly reduced and the phagocytosis as well as the migration of neutrophilic granulocytes is impaired to 50%. With these changes in laboratory data it is possible to identify patients which bear an increased risk with regard to infection.

The influence of age and particle number on absorption of polystyrene particles from the rat gut.

The bioavailability of polystyrene particles (1 microns) labelled with FITC (3M Company, Düsseldorf) was tested in rats after enteral administration. Since macromolecules and particles are preferentially transported in the lymph, the number of particles was counted in the lymph of the thoracic duct over a 6 h period. Uptake in young rats (6-8 wk) was compared with that in 5 and 9 mo animals. Young animals absorbed only 87 particles whereas a marked increase in the uptake of particles was observed in 5 mo animals (up to 775) but there was a decrease to 518 particles in older animals (9 mo). This number of particles is the total number of the entire output of the thoracic duct lymph over a 6 h period. In individual animals this number showed a considerable fluctuation over time. The volume of the collected lymph fluid was relatively constant (3.5 +/- 0.5 ml) in all animals. The bioavailability of the particles in the lymph was also influenced by the applied dose of particles. After intraduodenal administration of 3.7 x 10(5) particles only 18 particles could be found in the lymph. Increasing the dose to 3.7 x 10(7) particles raised the number of particles in the lymph to 116. The highest dose of 3.7 x 10(9) was correlated with the greatest absorption, 775 particles being found in the lymph. The uptake of particles from the gut thus depends on different factors including the age of the animal and the number of applied particles.

Intraocular lens dislocation in the bag.

We report a case in which an intraocular lens dislocated entirely within the capsular bag. The patient was myopic with a large anterior segment. A standard 5 mm x 6 mm phaco profile intraocular lens was found to be completely dislocated on the fifth postoperative day. The dislocated lens was replaced with another posterior chamber intraocular lens sutured at the ciliary sulcus.

The effect of topical treatment by timolol versus pilocarpine on visual field progression in chronic simple glaucoma.

OBJECTIVES: The objective of this study was to compare the intraocular pressure-lowering capacity, tolerability, and visual field conservation of topical timolol and pilocarpine at the concentrations usually prescribed.

Effect of timolol versus pilocarpine on visual field progression in patients with primary open-angle glaucoma.

BACKGROUND: Relatively few studies have been conducted linking decreasing intraocular pressure (IOP) to preservation of visual field. This investigation was conducted to determine if this link could be made and to compare the long-term effect of two ocular hypotensive agents on preservation of visual field. METHODS: In an observer-masked study, 189 patients with primary open-angle glaucoma received either timolol or pilocarpine by random allocation. The dose of antiglaucoma agent was increased from 0.25% to 0.5% twice daily for timolol or from 2% to 4% four times daily for pilocarpine if the initial IOP response was inadequate. After an on-treatment baseline, visual fields were followed every 4 months for 2 years using the Octopus program 32. RESULTS: Compared with timolol, significantly more patients receiving pilocarpine discontinued use because of inadequate IOP control (P < or = 0.01). By comparing the mean visual field scores, it can be seen that the pilocarpine group had a significantly worse score at all timepoints from month 4 to month 24. The pilocarpine group also had a greater mean number of test loci with decreased sensitivity of 5 or more decibels (dB) at all timepoints. The mean within-patient regression slope for timolol was 0.01 dB/month and for pilocarpine was -0.06 dB/month (P < 0.01). The study has shown that over a 2-year period, patients treated with pilocarpine 2% or 4% four times daily experienced a significantly greater visual field deterioration than that seen in patients receiving either 0.25% or 0.5% timolol twice daily. CONCLUSION: Although these data do not support a link between lowering of IOP and visual field preservation, treatment with timolol was associated with significantly less visual field loss than treatment with pilocarpine.

The role of cavitational activity in fragmentation processes by lithotripters.

The role of cavitation during shock wave exposure was poorly understood until now. Cavitational activity produces severe damage to nearby surfaces due to multiple high-speed liquid jets resulting from bubble collapse. These jet impacts can be made visible by microscopy. For investigating the presence of cavitational processes by shock waves outside and even inside of targets, we have performed the following experiments. Natural gallstones and artificial targets were examined microscopically with regard to the effects of shock pulses. Scanning electron and light microscopical investigations revealed regularly typical and uniform microjet impacts within the fissures and split lines. Since these experiments are the continuation of high-speed films of 10,000 frames/s of shock wave actions on targets, it is most likely that the shock wave produces at first split lines through the stone. Then liquid occupies these cracks. But the following shock waves create within these liquid-filled fissures cavitation and, therefore, cause the disintegration of the targets. It now becomes understandable why biliary lithotripsy is less effective than renal lithotripsy: bile fluid is a high-viscous liquid and, therefore, hinders the disintegration of stones more than low-viscous urine. Intervals between the application of shock waves in biliary lithotripsy, therefore, should improve the treatment results.

Experiences with lithotripters: measurements of standardized fragmentation.

A comparison of lithotripters in terms of the fragmentation efficacy was established by using artificial stones. Two hundred pulses were applied to identical calcium sulphate cubes at varied energy levels of different lithotripters. In the cubics the shock waves formed regular craters, which could be analyzed with regard to depth, diameter, and volume. Dimensions of the craters increased with increasing energy. Each shock wave source designed a typical crater form. Different efficacies of fragmentation within different lithotripters could be recognized. High focal peak pressures did not guarantee better fragmentation effects. By using different acoustic lenses in the same electromagnetic lithotripter, the influence of different focus zones of the shock wave on the fragmentation could be investigated without any changes of the energy input. Results clearly emphasize the possibility of an increase of fragmentation efficacy by changing only the focal zones and the distribution of energy within the focal area.

The mechanisms of stone disintegration by shock waves.

Through interpretation of high-speed films at 10,000 frames per second of shock wave action on kidney stones and gallstones, the mechanism of stone destruction was analyzed in detail. This shows that the interaction of the shock wave with the targets firstly produces fissures in the stone material. Liquid then enters these small cracks. The actual disintegration is caused later by the enormous violence of imploding cavitation bubbles within these small split lines. That cavitation acts inside the stone and causes fragmentation even within the human gallbladder could furthermore be demonstrated by using scanning electron microscopy. These results should lead to a different process in gallstone lithotripsy leaving intervals between the shock wave treatments. This will allow the viscous bile fluids to occupy the fissures of the stones more completely and, therefore, should increase the cavitational activity on the subsequent treatment with shock pulses.

Rapid insorption of small particles in the gut.

Little is known about the uptake of small particles by the epithelium of the gastrointestinal tract. In our study, we investigated the absorption and transport of synthetic and natural particles by means of scanning electron microscopy (SEM). In Wistar rats, closed loops of jejunum with intact mesenteric blood supply were established in ether anesthesia so that we might study the absorption of latex particles of different sizes. After variable absorption times, loops were removed and prepared for examination by microscopic techniques. The average surface of M-cells was 35 +/- 2 microns2, whereas the total number was dependent on follicle size. The proportion of M-cells to absorptive-like enterocytes on follicle epithelium was 1:12. Latex particles were found easily on the surface of M-cells, and for the most part they were surrounded by microfolds. In only 10 min from the time of application, latex beads were concentrated or even included within macrophages of the dome of lymph follicles. The results indicate that primary insorption of small particles occurs in M-cells of Peyer's patches, and time of insorption is dependent on particle size.

[Principles of particle resorption in the gastrointestinal tract]. / Prinzipien der Partikelresorption im Magen-Darm-Trakt.

The uptake of allergens by the epithelium of gastrointestinal tract is not sufficiently investigated. This is true especially for the absorption of small particles like spores and pollen. By means of scanning-electron-microscopy it is possible to locate particles easily and to observe absorption solutions of 0.5 micron and 1 micron latex particles, of 15 microns Urtica pollens and of 35 microns Lycopodium spores and further on by cannulation of the thoracic duct the transport of particles was investigated. After a short time of absorption latex particles were found to be concentrated on M-cells of Peyer's patches (PP) and were found in a close contact to macrophages inside the lymph follicles. There was a constant proportion of M-cells to absorptive-like cells in PP from about 1 to 12. Obviously all particles were also transported by thoracic duct lymph. The results obviously indicate: primary absorption of small particles occurs in M-cells of PP; absorption time is dependent on particle size and transport of particles is achieved by abdominal lymph.

[Can macromolecules be absorbed and what effect does the immune status have on it?]. / Werden Makromoleküle resorbiert und welchen Einfluss hat dabei die Immunitätslage?

It was shown by means of radioactive labelling that adult animals and humans are also able to absorb protein intact in its biological active form from the gastro-intestinal tract. A large part of these macromolecules retains their original biological activity. Depending on size, particles (polls, synthetic particles) can also be absorbed. The energy supply is not influenced by this phenomenon. It is postulated that a rudimentary mechanism present in the lymphatic system of the gastro-intestinal tract is involved. This absorbation mechanism receives information from the immune system about foreign and the body's own substances and about useful and unuseful nutriment. On the basis of investigations, carried out by us, it is speculated that immunological information takes place over the lymphatic tissue of the gastro-intestinal tract and is passed on the lymphatic system.

[Surgical indications in isolated splenic diseases]. / Operationsindikationen bei isolierten Milzkrankheiten.

In clinical routine isolated diseases of spleen are rare manifestations. Absolute criteria for splenectomy are massive bleeding, malignancy, hypertrophic cysts and signs of perforation. Most other cases are relative indications for total splenectomy. Awareness of the spleen's immunological function prompted a search for other methods of management. Therefore an individual consideration on further medical treatment is necessary. Total splenectomy should withdraw from nonoperative or partial operative management of spleen diseases. By a correct preoperative diagnosis criteria should be established for selection of patients most likely to derive benefit from splenectomy.

[Oxygen supply of the human small intestine in mechanical ileus]. / Die Sauerstoffversorgung des menschlichen Dünndarmes im mechanischen Ileus.

In 16 patients operated on for mechanically caused ileus and in 12 control patients (cholecystectomy) local PO2 of the small bower wall was determined by means of a multiwire Pt surface electrode constructed by Kessler and Lübbers. The ileus patients showed an increased pulse rate of 110 (90-115) vs 90 (80-110) beats/min and creatinine levels of 1.06 (0.79-1.45) vs 0.80 (0.70-0.88) mg%. (mean, 1.-3. quartile, P less than 0.05). Local PO2 values of the serosal site of the small bowel were significantly reduced in patients with ileus compared to the control group [22.5 (12.5-35) vvs 61.2 (53.0-71.0) torr.] Hypoxia of the bower in mechanically caused ileus could be demonstrated by local PO2 determination and underlines the demand of early decompression.

Overwhelming infection after splenectomy in spite of some spleen remaining and splenosis. A case report.

A fatal case of overwhelming postsplenectomy pneumococcal sepsis is presented occurring in a 37-year-old female 11 years after removal of the spleen because of traumatic rupture. The patient died 11 h after admission to hospital and about 32 h after sudden onset of illness. At necropsy splenic tissue, splenosis, disseminated intravascular coagulation, and thrombi within the arterioles consisting of gram-positive cocci and adrenal hemorrhage were found. The clinical, laboratory, and postmortem findings are described. Reports had been published of 41 other cases of overwhelming postsplenectomy infection (OPSI) in patients aged 20 years or more, but only three of these cases of OPSI syndrome occurred in spite of remaining splenic tissue. The longest interval between extirpation of spleen and subsequent sepsis was 42 years, indicating a small but lifelong risk of severe infection in asplenic patients. In view of the literature, the role of spleen in infection defence, the splenic function in blood clearance, and the prevention of postsplenectomy infections by antibiotic prophylaxis, pneumococcal vaccine, and reimplantation of autochthonous splenic tissue or infrared contact coagulation are discussed.