[Morphological Characteristics in SD-OCT and Fundus Autofluorescence in Different Ischaemic Retinopathies - Characterisation of a New, Temporary Hyperreflective Band]. / Morphologische Charakteristika im hochauflösenden OCT und in der Fundusautofluoreszenz bei verschiedenen ischämischen Retinopathien - Beschreibung einer zusätzlichen, temporären hyperreflektiven Bande.

BACKGROUND: The aim of this study was to investigate alterations in the neurosensory retinal morphology secondary to acute retinal ischaemic conditions. The observations were documented by spectral domain optical coherence tomography (SD-OCT, Heidelberg Engineering) and fundus autofluorescence (FAF) imaging. In addition, the occurrence of an additional hyperrefelctive band in the outer corneal layers is described. This observation was made during the evaluation of OCT images of patients with an acute loss of vision due to retinal ischaemia. PATIENTS/METHOD: SD-OCT images and FAF were used to observe the retinal structure of 26 subjects (36 to 96 years) with acute monocular visual impairment due to central retinal artery occlusion (CRAO), branch retinal artery occlusion (BRAO), anterior ischaemic optic neuropathy (AION) or impending central retinal vein occlusion were included. The main focus of attention was set on the transition of the outer nuclear layer (ONL) to outer plexiform layer (OPL). Furthermore measurements of the retinal thickness at the fovea, parafoveal and within the retinal layers were acquired and compared to corresponding points of the non-affected eyes. SD-OCT images were acquired with a combined SD-OCT and scanning laser ophthalmoscope (cSLO) imaging system using a linear cross hair scan and a 6 line radial scan of 6 mm length (ART mode on; average of 20 frames). RESULTS: SD-OCT revealed an additional highly reflective band located within the OPL. Morphological characteristics of this hyperdense band were a decreasing intensity with distance from the fovea, partially segmental occurrence and manifestation limited in time. FAF showed areas of increased and decreased signal intensity within the vessel arcade at the posterior pole. The regions of decreased FAF corresponded to perivenous regions and resemble the "frosted branches" sign seen in fluorescein angiography in patients with ocular ischaemia. CONCLUSIONS: The additional hyperreflective band observed in SD-OCT could represent a marker for retinal ischaemia in subjects without the presence of a complete vascular occlusion. The mid retinal localisation of the band within the OPL is situated at the locus of transition from retinal to choroidal oxygen supply where oxygen diffusion is weakest. Histopathologically the observed structure could represent activated microglial tissue induced by the hypoxia driven upregulation of inflammatory molecules aimed at ischaemia repair.

Frequency of specific anti-Toxoplasma gondii IgM, IgA and IgE in colombian patients with acute and chronic ocular toxoplasmosis.

We studied the frequency of specific anti-Toxoplasma IgM, IgA and IgE antibodies in serum of 28 immunocompetent Colombian patients, selected by ophthalmologists and with lesions that were compatible with ocular toxoplasmosis. Patients were classified in three groups: (i) group 1 consisted of ten patients with a first episode; (ii) group 2, with seven patients with a recurrence and (iii) group 3, consisted of eleven patients with chronic chorioretinal lesion without uveitis. We found that 10/28 (35%) of Colombian patients with ocular toxoplasmosis possessed at least one serological marker for Toxoplasma infection different from IgG. In group 1 (first episode), we found simultaneous presence of specific IgM plus IgA plus IgE in 1/10 (10%). In group 2 (recurrences) in 1/7 (14%) we found IgM and IgA test positives and in 1/7 (14%) we found IgM and IgE tests positives. In group 3 (toxoplasmic chorioretinal scar) the IgA serological test was positive in 2/11 (18%). These results show that serum IgM or IgA or IgE can be present during recurrences.

Tunable single frequency thulium:YAG microchip laser with external feedback.

By use of the reflection of an uncoated external etalon, a diode-pumped thulium-doped YAG microchip laser was forced into a single-frequency mode. The wavelength of the single-frequency radiation was tunable over 15 nm simply by translation of the etalon relative to the laser. Output powers of 45 mW were achieved in a monolithic setup that is insensitive to vibrations. The origin of the single-frequency oscillation is the wavelength-dependent reflection of the etalon, which is coupled back into the laser resonator. This method permits the combination of inherently stable, single-frequency resonator geometries such as microchips with laser materials that have broad tuning ranges.

Passive Q Switching of a Diode-Pumped 946-nm Nd:YAG Laser with 1.6-W Average Output Power.

As much as 1.6-W average output power was emitted in a simple setup from a diffusion-bonded Nd:YAG rod with 70-100-ns Q-switched pulses at 946 nm and repetition frequencies between 15 and 45 kHz at 22-W incident diode-pump power. A Cr(4+):YAG crystal with a bleachable loss of approximately 2.5% and a length of 0.5 mm was used as a saturable absorber. The extraction efficiency was 47% in comparison with the continuous-wave laser output power of 3.37 W in the free-running regime.

Cytokines derived from alveolar macrophages induce fever after bronchoscopy and bronchoalveolar lavage.

As much as one-third of patients develop fever and flu-like symptoms after fiberoptic bronchoscopy (FOB) and bronchoalveolar lavage (BAL) for yet unknown reasons. The aim of the present study was to investigate factors mediating these side effects. Fifty consecutive patients with various pulmonary diseases who underwent FOB without further interventions (n = 30) or combined with BAL (n = 20) were enrolled. Serum levels of the proinflammatory cytokines IL-1beta, IL-6, and TNF-alpha were determined directly prior to (t0), directly after (t1), and 6 h after (t2) the procedures by ELISA. In parallel, blood cultures were drawn at t2. At to and t1, generally only low cytokine concentrations could be detected. At t2, however, significant increases of cytokine levels were found. IL-6 and TNF-alpha were significantly higher in patients after BAL than in patients after FOB. Comparing patients who developed fever (n = 12) with those who did not (n = 38), irrespective of the endoscopic procedures performed, dramatic increases of all three cytokines were detected in febrile patients that were significantly higher than in patients without fever. In the FOB group only patients who received local anesthesia by prilocaine bolus injection into the airways via the working channel of the bronchoscope developed fever and increases of IL-6 and IL-beta, whereas patients anaesthetized by inhalation of a prilocaine aerosol remained afebrile and had slight IL-6 increases only. There was a highly significant correlation between IL-6 values at t2 and the number of BAL alveolar macrophages (r = 0.98). All blood cultures remained sterile. These results indicate that fever after FOB and BAL is induced by proinflammatory cytokines derived from alveolar macrophages activated by instillation of fluid into the airways.

High-power diode-pumped continuous-wave Nd(3+) lasers at wavelengths near 1.44 microm.

We demonstrate longitudinally diode-pumped operation of Nd:YAG and Nd:YAP lasers at the long-wavelength end of the (4)F(3/2) ? (4)I(13/2) transition in the eye-safe spectral region at 1444 and 1430 nm, respectively. Special crystal coatings were required for achievement of lasing at these wavelengths. Output powers of up to 4.9 and 2.2 W, with slope efficiencies of up to 22% and 8%, respectively, were achieved. Polarized operation of the Nd:YAG laser yielded output powers of 76% as compared with unpolarized operation. Because of thermal stress, both YAG and YAP crystals were fractured at roughly 25 W of absorbed longitudinal pump power.

All-solid-state continuous-wave doubly resonant all-intracavity sum-frequency mixer.

A new resonator design for doubly resonant continuous-wave intracavity sum-frequency mixing is presented. We generated 212 mW of coherent radiation at 618 nm by mixing the radiation of a 1080-nm Nd(3+):YAlO(3) laser and a 1444-nm Nd(3+):YAG laser. Two different mixing resonator setups and several nonlinear-optical crystals were investigated. So far output is limited by unequal performance of the two fundamental lasers and coating problems of the nonlinear crystals.

Efficient intracavity frequency doubling of a passively mode-locked diode-pumped neodymium lanthanum scandium borate laser.

We passively mode locked a diode-pumped neodymium lanthanum scandium borate laser with an antiresonant Fabry-Perot saturable absorber and achieved 2.8-ps pulses at an average output power of 400 mW and a pump power of 1.2 W. With Ti:sapphire laser pumping we obtained pulses as short as 1.6 ps. Intracavity doubling produced 190 mW of 531-nm light for a diode-pump power of 1.2 W, resulting in a conversion efficiency of 48% with respect to the fundamental and 16% with respect to the diode-pump power. Noise characterization of the laser demonstrates a trade-off between high conversion efficiency and low intensity noise.

[On the incidence of thoracal scoliosis in juveniles (author's transl)]. / Uber die Häufigkeit der Thorakalskoliose bei Jugendlichen.

Mass radiography in juveniles between 10 and 19 years of age in Westphalia pointed to a probable incidence of thoracal scoliosis of more than 10 degrees in about 4 per cent of the girls and 1.0--1.5 per cent among boys. In both girls and boys the convexity of the scoliosis is chiefly in the right direction, especially if the apex of the curvature is positioned in cranial direction or if the findings are very pronounced. In a few exceptional cases only the apex of curvature is above Th7. Hence, most of the patients can be adequately treated by means of one of the more recent methods of orthesis.

[Eclampsia. Incidence and therapy, results of the University Gynecological Clinic Göttingen]. / Eklampsie. Häufigkeit und Therapie, Ergebnisse der Universitäts-Frauenklinik Göttingen.

The occurrence of eclampsia in the last two decades in the women's hospital of the University of Goettingen was evaluated. In a total of 32,578 birth there was an incidence of 0.11%. Maternal mortality was 16.2%, perinatal mortality 19.5%. 73% of the patients were primiparae, 24.3% unmarried pregnant women. A regression of the frequency of eclampsia is seen within the last 20 years and certainly due to the intensive antenatal care.