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Abstract: The South Pole Acoustic Test Setup (SPATS) was built to evaluate the acoustic characteristics of the South Pole ice in the 10–100kHz frequency range, for the purpose of assessing the feasibility of an acoustic neutrino detection array at the South Pole. The SPATS hardware consists of four vertical strings deployed in the upper 500m of the South Pole ice cap. The strings form a trapezoidal array with a maximum baseline of 543m. Each string has seven stages equipped with one transmitter and one sensor module (glaciophone). Sound is detected or generated by piezoelectric ceramic elements inside the modules. Analogue signals are sent to the surface on electric cables where they are digitized by a PC-based data acquisition system. The data from all strings are collected on a central computer in the IceCube Laboratory from where they are sent to a central data storage facility via a satellite link or stored locally on tape. A technical overview of SPATS and its performance is presented. [Copyright &y& Elsevier]

The work presented here aimed at developing advanced thermoplastic composite laminates specifically dedicated to the fabrication of brush-armature supporting structures for the PEGASUS railgun of the French–German Research Institute of Saint-Louis. The main objective is to surpass the results obtained previously with glass-fiber-reinforced epoxy composites. Due to higher ductility and superior dynamic behavior of PEEK polymers, an S2-glass woven fabric preimpregnated with a PEEK resin was selected. The interlaminar resistance and tensile behavior of the material was characterized experimentally. The results led to the identification of the most suitable fiber/resin ratio and fabrication process for thick laminates. Several prototypes weighing about 320 g were produced and used for six shots with the PEGASUS railgun. Already in the first series of experiments, the laminates show a remarkable mechanical resistance, and a maximal velocity of 2440 m/s was obtained. [ABSTRACT FROM PUBLISHER]

Prcis: This prospectively collected case series of 56 eyes having PAUL glaucoma implant (PGI) surgery is the first to demonstrate its medium-term safety and effectiveness in what is essentially an exclusively Caucasian population., Background: To report 2-year outcomes from a single-center cohort undergoing PGI surgery., Methods: Prospectively collected data on patients undergoing PGI surgery at the University Eye Hospital Bonn, Germany, from April 2021 to September 2021., Results: Of 53 patients, 56 eyes were included. Complete and qualified success rates (95% CI) were 52% (37-66) and 89% (80-96) for criterion A ( intraocular pressure [IOP]≤21 mm Hg), 48% (36-61) and 79% (67-88) for criterion B (IOP≤18 mm Hg), 45% (32-57) and 64% (52-77%) for criterion C (IOP≤15 mm Hg) and 27% (16-40) and 38% (25-50) for criterion D (IOP≤12 mm Hg), respectively. Mean IOP decreased from 25.43 mm Hg (7-48 mm Hg) to 11.25 mm Hg (3-24 mm Hg) (reduction of 50%) after 24 months with a reduction of IOP-lowering agents from 3.50 (1-5) to 0.46 (0-3). One eye needed an injection of viscoelastic due to significant hypotony with AC shallowing; 3 eyes received a Descemet membrane endothelial keratoplasty because of persistent corneal decompensation; 9 eyes developed tube exposure which required conjunctival revision with additional pericardial patch graft, with 5 of these eyes eventually needing tube explantation. An intraluminal prolene stent was removed in 24 eyes (42.9%) after a mean time period of 5.67 months (2-15 m). Mean IOP before removal was 21.4 mm Hg (12-40 mm Hg) and decreased to 11.15 mm Hg (6-20 mm Hg)., Conclusions: PGI surgery is an effective procedure for reducing IOP and pressure-lowering therapy. The use of an intraluminal prolene stent impedes hypotony in the early postoperative phase and enables further noninvasive IOP lowering during the postoperative course., Competing Interests: Disclosure: The authors declare no conflicts of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Consecutive visitors to a public science event at Leipzig University were asked about their opinions/attitudes regarding their personal use of self-medication., Methods: A written questionnaire survey addressed (i) participants' characteristics, (ii) frequency of self-medication use in the last 12 months, (iii) symptoms/complaints most frequently considered applicable, (iv) preconditions, (v) limitations, (vi) risks, (vii) fears, (viii) medication information sources, (ix) influencing factors, and (x) reasons for decision making., Results: (i) A total of 189 visitors (median age: 29.0 years; Q25/Q75: 22.0/44.0) participated, of whom 64.0% were female, 38.6% had a university degree, 20.1% were in training, and 14.8% were licensed in a healthcare profession. (ii) A total of 59.3% of participants stated that they had used self-medication regularly in the last 12 months. The most common answers in the respective questions were (iii) headache, 86.2%; (iv) mild complaints/symptoms, 94.7%; (v) duration, 91.6%; (vi) "self-medication may cause adverse drug reactions", 94.2%; (vii) "developing a habituation effect", 58.7%; (viii) pharmacists, 93.7%; (ix) "physician's recommendation", 89.3%; (x) "intensity of complaints", 92.6%; and (vi) 61.3% believed that they could choose an appropriate self-medication., Conclusion: Younger and well-educated adults report using self-medication frequently and rate their expertise as high. Healthcare professionals are the preferred source of information.

Background: The eyeWatch System (EWS) (Rheon Medical, Lausanne, Switzerland) was developed as a glaucoma drainage device (GDD) to precisely control intraocular pressure (IOP) and thus prevent the development of postoperative hypotension and its complications., Objective: To report 1‑year outcomes from a single-center cohort undergoing EWS surgery., Material and Methods: Retrospective review of patients undergoing EWS surgery at the University Eye Hospital Bonn, Germany from May 2021 to September 2022., Results: A total of 5 eyes of the first 5 consecutive patients treated with the EWS were included in this study. The mean preoperative IOP was 34.6 mm Hg (23-45 mm Hg) which was reduced to 12.2 mm Hg (9-18 mm Hg) with a mean reduction of 60%. Local pressure-lowering therapy was reduced from 2.8 agents preoperatively (1-4) to 0.6 agents after 1 year. All patients achieved the target IOP of below 21 mm Hg including 4 patients without any medication. The complication rate was low. One patient had to undergo two surgical revisions as the IOP was elevated to over 30 mm Hg after surgery and tube exposure became apparent during the course of the follow-up so that a second donor patch was sutured on. The same patient had an elevated IOP >30 mm Hg after a cMRI examination, so that a reduction of IOP by adjusting the EWS using the eyeWatch pen (EWP) was performed. IOP adjustments with the eyeWatch pen (EWP) were performed in 4 of 5 patients in the first year after surgery; the mean IOP before adjustment was 21.33 mm Hg (15-37 mm Hg) which was reduced to a mean of 8.58 mm Hg (4-16 mm Hg)., Conclusion: The EWS effectively lowers IOP and the amount of necessary pressure-lowering therapy. With the EWP postoperative adjustments of IOP are possible without further invasive measures., (© 2024. The Author(s).)

Background: To report one-year outcomes from a single-centre cohort undergoing PAUL® Glaucoma Implant (PGI) surgery., Methods: Retrospective review of patients undergoing PGI surgery at the University Eye Hospital Bonn, Germany, from April 2021 to September 2021., Results: Forty-five eyes of 41 patients were included. Qualified and complete success rates (95% CI) were 95.6% (88.9%-100%) and 73.3% (60%-86.7%) for Criterion A (IOP ≤ 21 mmHg), 84.4% (73.3%-93.3%) and 74.4% (51.1%-80.0%) for Criterion B (IOP ≤ 18 mmHg), 62.2% (48.9%-75.6%) and 46.7% (31.2%-62.2%) for Criterion C (IOP ≤ 15 mmHg) and 26.7% (13.3%-40.0%) and 22.2% (11.1%-33.3%) for Criterion D (IOP ≤ 12 mmHg), respectively. Mean IOP decreased from 26.1 mmHg (7-48 mmHg) to 12.0 mmHg (3-24 mmHg) (reduction of 48.83%) after 12 months with a reduction of IOP-lowering agents from 0.5 (0-3). One eye (2.2%) needed an injection of viscoelastic due to significant hypotony with AC shallowing, and four eyes (8.9%) developed choroidal detachments due to hypotony which resolved without further interventions after 6 weeks. Three patients (6.7%) developed tube exposure which required conjunctival revision with an additional pericardial patch graft. An intraluminal prolene stent was removed in 19 eyes (42.2%) after a mean time period of 8.4 months (2-12 m). Mean IOP before the removal was 21.9 mmHg (12-38 mmHg) and decreased to 11.3 mmHg (6-16 mmHg)., Conclusions: PGI surgery is an effective procedure for reducing IOP and pressure-lowering therapy. An intraluminal prolene stent impedes hypotony in the early postoperative phase and enables further IOP lowering without additional interventions during the postoperative course., (© 2023 The Authors. Clinical & Experimental Ophthalmology published by John Wiley & Sons Australia, Ltd on behalf of Royal Australian and New Zealand College of Ophthalmologists.)

Prcis: This retrospective study of 264 eyes having inferior quadrant trabectome surgery confirms its safety and relative effectiveness. Most patients however still require IOP-lowering agents, and a considerable proportion may need additional glaucoma surgery., Purpose: To report outcomes from a large single-center cohort of inferiorly-applied trabectome surgery., Patients and Methods: Retrospective review of patients undergoing trabectome surgery for chronic open angle glaucoma (COAG) at the University Eye Clinic Bonn, Germany, from 2012 to 2020., Results: Two hundred sixty-four eyes of 206 patients with COAG were included. The mean review period was 45.43 (range 12-101) months. One hundred five eyes (39.8%) underwent standalone surgery, of which 74 were pseudophakic and 31 phakic. The mean preoperative IOP was 17.58 mm Hg (range 12-50 mm Hg). One hundred five eyes (39.8%) developed a 'failure event' according to pre-defined criteria at a mean interval of 14.8 months postoperative. In absolute terms, 211 patients (79.9%) had a long-term IOP >14 mm Hg at 7.6 months, 174 patients (65.9%) >16 mm Hg at 10.6 months, 127 patients (48.1%) >18 mm Hg at 10.9 months, and 77 patients (29.2%) >21 mm Hg at 11.1 months. Over a five-year period, overall mean IOP remained stable at 13 mm Hg. The majority of patients were still on glaucoma drops (the mean number reduced from 2.9 to 2.7 agents). Subgroup analyses showed that a higher preoperative IOP was a positive predictor for failure, whereas combined surgery (with phaco) had better IOP outcomes (16.5 mm Hg vs. 19.3 mm Hg, respectively). Forty-one patients (15.5%) developed minor complications: 22 had high postoperative IOP within 3 months, 11 developed a self-resorbing hyphema, and 6 had fibrinous uveitis., Conclusions: Trabectome surgery is a safe and relatively effective procedure for lowering IOP, but most patients still need IOP-lowering agents, and a considerable proportion may need additional glaucoma surgery within a relatively short time. Inferior quadrant treatment may result in inferior IOP outcomes when compared with nasal quadrant surgery., Competing Interests: Disclosure: The authors declare no conflict of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Background: The implantation of a collagen gel micro-stent (XEN45 ® ) as a minimally invasive form of glaucoma surgery (MIGS) after a failed trabeculectomy (TE) may be an effective option with few risks. This study investigated the clinical outcome of XEN45 ® implantation after a failed TE, with follow-up data of up to 30 months., Materials and Methods: In this paper, we present a retrospective review of patients undergoing XEN45 ® implantation after a failed TE at the University Eye Hospital Bonn, Germany, from 2012 to 2020., Results: In total, 14 eyes from 14 patients were included. The mean follow-up time was 20.4 months. The mean time duration between the failed TE and XEN45 ® implantation was 110 months. The mean intraocular pressure (IOP) decreased from 17.93 mmHg to 12.08 mmHg after one year. This value increased again to 17.63 mmHg at 24 months and 16.00 mmHg at 30 months. The number of glaucoma medications decreased from 3.2 to 0.71, 2.0, and 2.71 at 12, 24, and 30 months, respectively., Conclusions: XEN45 ® stent implantation after a failed TE did not lead to an effective long-term decrease in IOP and glaucoma medications in many patients in our cohort. Nevertheless, there were cases without the development of a failure event and complications, and others in whom further, more invasive surgery was delayed. XEN45 ® implantation in some failed trabeculectomy cases may, therefore, be a good option, especially in older patients with multiple comorbidities.

Background: Glaucoma drainage devices (GDD) are an invasive procedure for the treatment of glaucoma. The PAUL® Glaucoma Implant (PGI) has been developed as a new, innovative therapeutic procedure. The PGI differs from previous GDD with regard to the smaller size of the drainage tube., Objective: This study analyses 6‑months results of the PGI in terms of effectiveness and safety., Methods: A database of patients treated with the PGI at the University Eye Hospital Bonn was created and continuously updated based on follow-up controls. Statistical analysis was performed using SPSS Statistics for Windows (IBM Corp., Armonk, NY, USA)., Results: A total of 53 eyes of the first 51 consecutive patients treated with the PGI were included in this study. Mean intraocular pressure was 26.62 mmHg (7-48 mmHg) preoperatively and reduced to 12.20 mmHg (3-22 mmHg) after 6 months. Local pressure-lowering therapy was reduced from 3.37 agents preoperatively to 0.30 agents after 6 months. The complication rate was low; only 3 patients (5.8%) had persistent hypotony. In 16 patients, the intraluminal prolene stent was removed in the postoperative course after an average of 2.9 months. Thereafter, these patients experienced a reduction of intraocular pressure from 22.21 to 11.07 mmHg., Conclusion: The PAUL® Glaucoma Implant is a safe treatment modality that can successfully reduce intraocular pressure to a low level and reduce pressure-lowering local therapy. It has a low complication rate, particularly regarding postoperative hypotony., (© 2022. The Author(s).)

Objective: To test whether the combined application of dexamethasone (DEXA) and 3,5-dimethyl-3'-isopropyl-L-thyronine (DIMIT) induces the synthesis of surfactant protein A (SP-A) mRNA at a higher rate than both substances given alone?, Study Design: Organoid culture of fetal rat lungs (Wistar rats; day 19 of gestation) was prepared. After 48h of incubation we added DEXA (10(-5), 10(-7), 10(-8) and 10(-9)mol/l), DIMIT (10(-5), 10(-7) and 10(-9)mol/l) and the combination of DEXA in 10(-8)mol/l with various concentrations of DIMIT. After another 48h of incubation, northern blot and hybridization with a 32P-labeled SP-A cDNA probe was performed. One-way-variance-analysis with a Scheffé-test, Levene-test and one-sample-t-test were used for statistical analysis., Results: DEXA alone above 10(-8)mol/l resulted in a significant increase, DIMIT resulted in a decrease of SP-A mRNA induction. Combined application of DIMIT and DEXA resulted in a significant increase compared to the controls. Compared to DEXA alone in 10(-8)mol/l, we found an increased induction, but the data were not significant., Conclusions: The combined application of DEXA and DIMIT shows a higher induction of SP-A mRNA than both drugs given alone.

Neutrinos are elementary particles that carry no electric charge and have little mass. As they interact only weakly with other particles, they can penetrate enormous amounts of matter, and therefore have the potential to directly convey astrophysical information from the edge of the Universe and from deep inside the most cataclysmic high-energy regions. The neutrino's great penetrating power, however, also makes this particle difficult to detect. Underground detectors have observed low-energy neutrinos from the Sun and a nearby supernova, as well as neutrinos generated in the Earth's atmosphere. But the very low fluxes of high-energy neutrinos from cosmic sources can be observed only by much larger, expandable detectors in, for example, deep water or ice. Here we report the detection of upwardly propagating atmospheric neutrinos by the ice-based Antarctic muon and neutrino detector array (AMANDA). These results establish a technology with which to build a kilometre-scale neutrino observatory necessary for astrophysical observations.

We discuss recent measurements of the wavelength-dependent absorption coefficients in deep South Pole ice. The method uses transit-time distributions of pulses from a variable-frequency laser sent between emitters and receivers embedded in the ice. At depths of 800-1000 m scattering is dominated by residual air bubbles, whereas absorption occurs both in ice itself and in insoluble impurities. The absorption coefficient increases approximately exponentially with wavelength in the measured interval 410-610 nm. At the shortest wavelength our value is approximately a factor 20 below previous values obtained for laboratory ice and lake ice; with increasing wavelength the discrepancy with previous measurements decreases. At ~415 to ~500 nm the experimental uncertainties are small enough for us to resolve an extrinsic contribution to absorption in ice: submicrometer dust particles contribute by an amount that increases with depth and corresponds well with the expected increase seen near the Last Glacial Maximum in Vostok and Dome C ice cores. The laser pulse method allows remote mapping of gross structure in dust concentration as a function of depth in glacial ice.

Aim: To determine the quality of prenatal sonographic weight estimation, comparing breech and vertex presentations., Method: In 147 breech presentations (BP) and 149 vertex presentations (VP), the biparietal head diameter (BPD), the fronto-occipital head diameter (FOD) and the transverse abdominal diameter (ATD) were measured. From these data, the weight was estimated, using Shepard's formula before 28 weeks and Hansmann's thereafter, and compared to the delivery weight. Both formula were modified to incorporate the virtual BPD (vBPD), derived from the BPD, FOD and the calculated head circumference. In the BP group, the role of examiner skills was evaluated, comparing the accuracy of experienced (DEGUM II qualifications) and average individuals., Results: The accuracy for BP was nearly identical to that for VP (= 0.915 vs. = 0.929). The examiners' qualifications had a detectable but not significant influence on the results (= 0.942 vs. = 0.892)., Conclusion: Ultrasound measurements yield comparable results in both BP and VP, if the vBPD is used. In our opinion, ultrasonic weight estimation is a useful adjunct when determining the manner of delivery in BP.

The diagnosis of a premature rupture of membranes presents no problem in the vast majority of cases. However, a reliable diagnosis is clinically not possible in about 10%. Most methods available lack the necessary sensitivity and specificity. Since the clinical consequences of a false diagnosis are considerable (overtreatment for false-positive and risk of infection for false-negative results), it is essential to clinically establish new, minimally invasive methods with higher predictive powers. In the present study we compared: the AMNI Check for detection of insulin-like growth-factor binding protein 1 (IGFBP-1); a membrane immunoassay for detection of fetal fibronectin (fFn); pH indicator paper; and, to verify a rupture of membranes in unclear cases, amniocentesis with installation of indigo carmine. The examination was performed in a group of 75 patients, 35 with and 40 without rupture of the membranes. The best results were obtained for the AMNI Check (sensitivity and negative correctness 100%, specificity and positive correctness 83%). With the same sensitivity and negative correctness, the membrane immunoassay for fFn achieved a specificity of 70% and a positive correctness of 74%. The pH indicator paper had the lowest predictive value (sensitivity 94%, negative correctness 93%, specificity 63%, positive correctness 69%). Both the AMNI Check and the test for detection of fetal fibronectin can be recommended for reliable exclusion of premature rupture of membranes. Amniocentesis should however be performed in uncertain cases with a positive test result. Nevertheless, considerable reduction of this invasive method is possible.

The therapeutic approach to ectopic pregnancy (EP) has changed over the last decade. A prerequisite for a differentiated management is an early diagnosis of EP. This can be achieved by transvaginal sonography (TVS). The purpose of this study was to evaluate the accuracy of TVS in the diagnosis of EP. 184 patients with clinically suspected ectopic pregnancy were examined by TVS. In 103 cases suspicion of EP was confirmed, in 81 cases it was ruled out. All cases were evaluated by laparoscopy, D&C, serial HCG determinations or sonographic follow-up in case of an intrauterine pregnancy. Sensitivity of TVS in the diagnosis of EP was 96%, specificity 88%, the positive predictive value was 89%, the negative predictive value was 95%. Four cases with a false negative result at TVS were very early in pregnancy and were subjected to laparoscopy because of persistent high HCG values without demonstration of an intrauterine pregnancy. Five cases of sonographically confirmed ectopic pregnancies were missed by the first laparoscopy. These cases required intervention because of clinical symptoms and had low levels of HCG. TVS has a high diagnostic accuracy in the diagnosis of ectopic pregnancy.

Since the treatment of premature ruptures of membranes is not only controversial in the German but also in the international literature, we performed a survey of all obstetrics departments in Germany. From a total of 843 hospitals, 444 questionnaires were returned for evaluation (52.7%). The purpose was to determine which diagnostic and therapeutic regimes are used and how these agree with the literature. In addition to questions on the type of hospital, birth rates with a percentage of premature births and applied diagnostic parameters, our special interest focused on therapy, particularly with regard to prophylactic antibiotic application, tocolytic treatment and lung maturity induction. Prophylactic antibiotics are used in 36.7% and prophylactic tocolytic therapy in 41.7% of the departments. Interestingly, lung maturity induction was performed in 93.5%, in part even before the 28th week of pregnancy, although the effect of this therapy has not yet been proven at a very early stage of gestation. Due to the different views in the literature and, in part, a lack of basic scientific data, it seems there is a preference for the procedure, in which the best personal experience has been made. Because premature ruptures of the membranes is responsible for 30-40% of premature births, it is urgently necessary to clarify this controversial problem by large multicenter studies so that the treatment of early premature ruptures of the amnion can be founded on a rational basis.

Although fetal lung maturity determination is carried out more and more rarely in the German-speaking area, a reliable information about the degree of lung maturity is still very important in the care of high-risk pregnancies. The side effects and costs of a postpartal surfactant administration can be avoided if lung maturity is proved. Indications for determination of fetal lung maturity are the threatening preterm delivery and the premature rupture of membranes before the 34th week of gestation and uncertain gestational age. Furthermore, in preeclampsia resp. in diabetes mellitus, which is difficult to control, premature delivery may be necessary. To improve lung maturity testing we introduce a new "sequence scheme" containing three lung maturity tests which are easy to carry out (in the following sequence: Amniostat-FLM ultrasensitive, counting of the lamellar bodies in amniotic fluid, surfactant/albumin ratio with TDx-FLM). The principle of this scheme is, that if any of these three tests indicates lung maturity, the sequence is terminated and no further test is performed. Only if all three tests indicated immaturity, the child was at risk for RDS. In 87 amniotic fluid samples with 7 RDS-cases, we achieved high predictive values for lung maturity (specificity 90%, sensitivity 100%, predictive value of positive test 47%, predictive value of negative test 100%). In 62% only one test was needed for lung maturity determination. It is possible to use other combinations in such a scheme (e.g. the L/S ratio). This might lead to equal or perhaps better results. An advantage of this suggested "sequence scheme" is that it can be performed in any clinic.

Increase in fetal surfactant synthesis and lung maturity is caused by the glucocorticoidal induction of enzymes required for phosphatidylcholine (PC) synthesis towards the end of gestation. The regulation of gestational age-dependent induction of PC synthesis by glucocorticoids is still unclear. Since 11-beta-hydroxysteroid dehydrogenase (11 beta-HSD) activity and its metabolising capacity for glucocorticoids have been suggested to play a central role in this regulation, we measured the gestational age-dependent changes in 11 beta-HSD and PC synthesizing enzymes in lung and liver of fetal rat. The activity of cholinephosphate cytidyltransferase (CCT; key enzyme in PC synthesis), choline phosphotransferase (CPT) and lysolecithin acyltransferase (LAT) were found to increase gradually in the lung towards the end of gestation, reached peak values at term followed by a decrease of activity reaching finally adult levels. Only CK activity exhibited constant levels until term followed by a slight increase after the birth. In comparison with the lung, the liver enzymes followed a similar pattern, but at a higher rate of activity except for CCT which was higher in the lung. The activity of 11 beta-HSD in fetal lung microsomes was detectable from day 20 and increased towards the end of gestation in the lung and liver of the rat. Oxidase activity was always found to exceed the reductase activity. The activity of 11 beta-HSD continued to increase after delivery and reached peak levels in adult animals in both organs. In order to test the hypothesis, whether 11 beta-HSD activity and PC synthesis are induced by increasing endogenous glucocorticoidal levels, we examined on day 19 of gestation the effect of dexamethasone (DEXA) on enzymatic activities (11 beta-HSD, CCT) and on [14C]choline incorporation in phosphatidylcholine in fetal lung organoid cultures. Additionally, changes in CCT activity in fetal lungs after maternal administration of DEXA were measured. DEXA accelerated 11 beta-HSD and CCT activities as well as [14C]choline incorporation. We conclude, that endogenous glucocorticoids induce PC synthesis as well as 11 beta-HSD activity in lung and liver of the fetal rat. Fetal PC synthesis is not altered by increasing 11 beta-HSD levels, because the increase of free serum corticosterone levels apparently exceeds the metabolising capacity of 11 beta-HSD towards term.

The modulation of the intracellular glucocorticoidal effect on surfactant synthesis of the fetal lung by the metabolic capacity of 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD) could be an important factor in lung maturation. The kinetic properties of microsomal 11 beta-HSD of the rat lung are characterized with respect to product inhibition, substrate specificity, effect of electrolytes or trace elements, and the dependence of the oxidase reductase (OR) ratio on incubation conditions. With NADP+ product inhibition of the reductase was demonstrated. The most common trace elements and electrolytes exhibited no effect on the activity of 11 beta-HSD. It is shown that the OR ratio was strongly dependent on assay conditions. With optimal assay conditions oxidase activity exceeds reductase activity in adult and fetal rat lung microsomes (OR ratio > 1). Thus, glucocorticoids are mainly metabolized to their inactive forms. The enzyme activity in the adult is about 10 times higher than in the fetal lung. The low enzyme activity in fetal lungs could be the reason why the glucocorticoidal effects on surfactant synthesis are not suppressed despite the predominance of oxidase activity.