A Hansel & Gretel breadcrumb-style dynamically deployed communication network paradigm using mesh topology for planetary subsurface exploration

We introduce a dynamically deployed communication network (DDCN) paradigm using mesh topology in support of a distributed robotic multi-agent approach for the autonomous exploration of subsurface environments, i.e., caves, lava tube caves, lakes, and oceans, etc. The DDCN, comprising wireless communication beacons autonomously deployed via a rover or submersible in a Hansel & Gretel-inspired breadcrumb style, allows for the longest and most robust communication link between subterranean robotic agent(s) within, e.g., a lave tube cave or a subsurface ocean, and associated surface-borne robotic agent(s). Moreover, we briefly touch on the development of a robotic testbed and wired/wireless communication beacons in support of such astrobiological surface/subsurface exploration scenarios. Candidate lava tube caves have been identified on the Moon and Mars, raising possibilities for planetary exploration, astrobiology, habitat construction for future astronauts, and potential mining operations. Subterranean caverns, and in particular relatively deep lava tube caves, provide a possible refuge for life under otherwise challenging planetary surface conditions, and, as such, are of prime astrobiological relevance. Lava tube caves or other subsurface environments may also be suitable habitats for astronauts and subsequent human settlement but are yet to be explored in part due to difficulties ensuring continued communication with a robotic probe inside these environments. Moreover, the existence of subsurface oceans on ocean worlds, such as Europa, Enceladus, and Titan, has been backed by varying levels of evidence since the 1980s, though there has been no confirmation, i.e., direct observation, thus far. Such environments are also shielded from radiation, and, in combination with the hypothesized presence of water, are additional candidate environments for finding extant or fossilized life. The DDCN paradigm introduced herein directly addresses NASA's Space Technology Grand Challenges - "All Access Mobility" by enabling the most unconstrained exploration of subsurface environments through a dynamic communication network which ensures transmission of data from and possibly commands to the subsurface robotic probe. 2023 COSPAR. Published by Elsevier B.V. All rights reserved.

VISTATM: Visual Impairment Subtle Touch AidTM - a range detection and feedback system for sightless navigation

We devised a low-tech, low-cost, robust, and minimally obtrusive navigational travelling aid to be paired with and bolster standard white cane use for people with visual impairments. The device combines ultrasonic range detection with proportional vibrational output. The navigational aid was devised using a sensing belt equipped with independent ultrasonic sensors for distance measurements. Sensors were mounted using adjustable mobile clips to allow for user variability. The sensing belt was connected to a stimulation belt affixed to the ribcage. The stimulation belt used vibrating motors with vibration proportional to the distance between the belt wearer and surrounding obstacles sensed by corresponding ultrasonic sensors. The device was validated through preliminary testing on blindfolded, but fully sighted, persons and one blind person (all authors) in navigating a novel environment without supplemental aid. Testing sessions varied from 45 to 90 min. In preliminary tests, the devised ultrasonic-sensor-belt and vibration-actuator-equipped belt combination was capable of informing users of surrounding obstacles in real-time while navigating a hallway with several turns.

Conceptual design considerations for a wireless intraocular pressure sensor system for effective glaucoma management

As a leading form of preventable visual impairment, it is imperative to assess glaucoma treatment as a function of intraocular pressure (IOP). IOP can spike throughout the day. This necessitates a device that can (1) monitor IOP outside of clinical visits by providing a memory when IOP exceeds a set threshold indicating the possibility for glaucomatous damage to occur; and (2) accurately assess IOP. Both requirements point ultimately towards the development of an implantable device. The Wireless Intraocular Pressure Sensor System (WIPSS) devised by our team uses optical technologies and may assist an overseeing clinician with assessing glaucoma treatment efficacy and avoiding irreversible glaucomatous visual field loss downstream.

Publisher Correction: Nanobiophotonics: Nature-inspired sensors

In the version of this News and Views article originally published, in the author's e-mail address, the domain was incorrectly given as 'e-mail.arizona.edu'; it should have read 'email.arizona.edu'. This has now been corrected in the online versions.

The Argyre Region as a Prime Target for in situ Astrobiological Exploration of Mars

At the time before ∼3.5 Ga that life originated and began to spread on Earth, Mars was a wetter and more geologically dynamic planet than it is today. The Argyre basin, in the southern cratered highlands of Mars, formed from a giant impact at ∼3.93 Ga, which generated an enormous basin approximately 1800 km in diameter. The early post-impact environment of the Argyre basin possibly contained many of the ingredients that are thought to be necessary for life: abundant and long-lived liquid water, biogenic elements, and energy sources, all of which would have supported a regional environment favorable for the origin and the persistence of life. We discuss the astrobiological significance of some landscape features and terrain types in the Argyre region that are promising and accessible sites for astrobiological exploration. These include (i) deposits related to the hydrothermal activity associated with the Argyre impact event, subsequent impacts, and those associated with the migration of heated water along Argyre-induced basement structures; (ii) constructs along the floor of the basin that could mark venting of volatiles, possibly related to the development of mud volcanoes; (iii) features interpreted as ice-cored mounds (open-system pingos), whose origin and development could be the result of deeply seated groundwater upwelling to the surface; (iv) sedimentary deposits related to the formation of glaciers along the basin's margins, such as evidenced by the ridges interpreted to be eskers on the basin floor; (v) sedimentary deposits related to the formation of lakes in both the primary Argyre basin and other smaller impact-derived basins along the margin, including those in the highly degraded rim materials; and (vi) crater-wall gullies, whose morphology points to a structural origin and discharge of (wet) flows.

Operational challenges of retinal prostheses

Two computational models for research on retinal implants are presented. In the first model, the electric field produced by a multi-electrode array in a uniform retina is calculated. It is shown how cross talk of activated electrodes and the resulting bunching of field lines in monopole and dipole activation prevent high resolution imaging with retinal implants. Furthermore, it is demonstrated how sequential stimulation and multipolar stimulation may overcome this limitation. In the second model a target volume, i.e., a probe cylinder approximating a bipolar cell, in the retina is chosen, and the passive Heaviside cable equation is solved inside this target volume to calculate the depolarization of the cell membrane. The depolarization as a function of time indicates that shorter signals stimulate better as long as the current does not change sign during stimulation of the retina, i.e., mono-phasic stimulation. Both computational models are equally applicable to epiretinal, subretinal, and suprachoroidal vision implants.

Artificial vision support system (AVS(2)) for improved prosthetic vision

State-of-the-art and upcoming camera-driven, implanted artificial vision systems provide only tens to hundreds of electrodes, affording only limited visual perception for blind subjects. Therefore, real time image processing is crucial to enhance and optimize this limited perception. Since tens or hundreds of pixels/electrodes allow only for a very crude approximation of the typically megapixel optical resolution of the external camera image feed, the preservation and enhancement of contrast differences and transitions, such as edges, are especially important compared to picture details such as object texture. An Artificial Vision Support System (AVS(2)) is devised that displays the captured video stream in a pixelation conforming to the dimension of the epi-retinal implant electrode array. AVS(2), using efficient image processing modules, modifies the captured video stream in real time, enhancing 'present but hidden' objects to overcome inadequacies or extremes in the camera imagery. As a result, visual prosthesis carriers may now be able to discern such objects in their 'field-of-view', thus enabling mobility in environments that would otherwise be too hazardous to navigate. The image processing modules can be engaged repeatedly in a user-defined order, which is a unique capability. AVS(2) is directly applicable to any artificial vision system that is based on an imaging modality (video, infrared, sound, ultrasound, microwave, radar, etc.) as the first step in the stimulation/processing cascade, such as: retinal implants (i.e. epi-retinal, sub-retinal, suprachoroidal), optic nerve implants, cortical implants, electric tongue stimulators, or tactile stimulators.

Der Einfluß von Sulfoxylaten auf die Photoleitfähigkeit chemisch hergestellter Bleisulfidschichten / The Influence of Sulfoxylates on the Photoconductivity of Chemically Deposited Lead Sulfide Layers

In addition to the procedure of partial oxidation of lead sulfide layers in order to increase their photoconductivity it was found that reduction may have a similar effect.

When used as additives to the conventional thiourea-plumbite solution, the compounds aminoiminomethanesulfinic acid (1), rongalite or sodium dithionite, which all may form sulfoxylate in aqueous solution, enhance the photoconductivity of the deposited layers.

Addition of H2O2 or PbO2 has a similar, less pronounced effect, which may also be ascribed to the intermediate oxidation of thiourea to 1.

Planetary imaging in powers of ten: a multiscale, multipurpose astrobiological imager

Contextual, multiscale astrobiological imaging is necessary to discover, map, and image patchy microbial colonization in extreme environments on planetary surfaces. The large difference in scale--several orders of magnitude--between search environment and microorganisms or microbial communities represents a challenge, which to date no single imaging instrument is able to overcome. In support of future planetary reconnaissance missions, we introduce an adapter-based imager, built from an off-the-shelf consumer digital camera, that offers scalable imaging ranging from macroscopic (meters per pixel) to microscopic (micrometers per pixel) imaging, that is, spanning at least 6 orders of magnitude. Magnification in digital cameras is governed by (1) the native resolution of the CCD/CMOS chip of the camera, (2) the distance between camera and object to be imaged (focal length), and (3) the built-in optical and digital zoom. Both telezoom and macro mode alone are usually insufficient for microscopic imaging. Therefore, the focal distance has to be shortened, and the native CCD resolution of the camera has to be increased to attain a microscopic imaging capability. Our adapter-based imager bridges the gap between macroscopic and microscopic imaging, thereby enabling for the first time contextual astrobiological imaging with the same instrument. Real-world applications for astrobiology and planetary geology are discussed, and proof-of-concept imagery taken with our prototype is presented.

Prospective three-dimensional analysis of structure and function in vitreomacular adhesion cured by pharmacologic vitreolysis

PURPOSE

To prospectively characterize macular structure and function as assessed by combined three-dimensional spectral-domain optical coherence tomography and scanning laser ophthalmoscopy and 3D computer-automated threshold Amsler grid, respectively, in a patient undergoing pharmacologic vitreolysis for vitreomacular adhesion with tractional cysts.

METHODS

Combined 3D optical coherence tomography and scanning laser ophthalmoscopy measured macular volume and 3D computer-automated threshold Amsler grid quantified central visual field function by determining the absolute percent magnitude lost (cumulative value of total visual field loss over all tested levels) before and for a period of 6 months after pharmacologic vitreolysis for vitreomacular adhesion with a single intravitreal injection of microplasmin (125 μg; ThromboGenics).

RESULTS

Ocriplasmin pharmacologic vitreolysis released vitreomacular adhesion by 2 weeks and decreased macular volume from 0.32 μL to 0.15 μL by 1 year after injection. There was a concomitant 4-fold improvement in visual function as measured by 3D computer-automated threshold Amsler grid (percent of central visual field lost) and Snellen visual acuity improved from 20/200 to 20/40.

CONCLUSION

For assessing macular function improvement in conjunction with structural reintegration after pharmacologic vitreolysis for vitreomacular adhesion, 3D computer-automated threshold Amsler grid is a useful tool. Both 3D measurements quantitatively characterized the resolution of this patient's vitreomacular adhesion, suggesting that this is a useful approach to quantifying macular structure and function as indices of the severity of disease and the response to therapy.

Probable hypersensitivity reaction to vancomycin associating rash, fever and neutropenia

We describe the case of a 54-year old woman with breast cancer who was treated by vancomycin for febrile neutropenia due to a methicillin-resistant Staphyloccocus epidermidis infection of a surgically implanted catheter. She developed an hypersensitivity reaction to vancomycin associating neutropenia, fever, skin rash and elevated liver enzymes following re-challenge with vancomycin after having been misdiagnosed with septic thrombophlebitis. Following this re-challenge, neutrophils count fell dramatically but promptly resolved after cessation of vancomycin.

Microcomputer-based artificial vision support system for real-time image processing for camera-driven visual prostheses

It is difficult to predict exactly what blind subjects with camera-driven visual prostheses (e.g., retinal implants) can perceive. Thus, it is prudent to offer them a wide variety of image processing filters and the capability to engage these filters repeatedly in any user-defined order to enhance their visual perception. To attain true portability, we employ a commercial off-the-shelf battery-powered general purpose Linux microprocessor platform to create the microcomputer-based artificial vision support system (microAVS(2)) for real-time image processing. Truly standalone, microAVS(2) is smaller than a deck of playing cards, lightweight, fast, and equipped with USB, RS-232 and Ethernet interfaces. Image processing filters on microAVS(2) operate in a user-defined linear sequential-loop fashion, resulting in vastly reduced memory and CPU requirements during execution. MiccroAVS(2) imports raw video frames from a USB or IP camera, performs image processing, and issues the processed data over an outbound Internet TCP/IP or RS-232 connection to the visual prosthesis system. Hence, microAVS(2) affords users of current and future visual prostheses independent mobility and the capability to customize the visual perception generated. Additionally, microAVS(2) can easily be reconfigured for other prosthetic systems. Testing of microAVS(2) with actual retinal implant carriers is envisioned in the near future.

CYCLOPS: A mobile robotic platform for testing and validating image processing and autonomous navigation algorithms in support of artificial vision prostheses

While artificial vision prostheses are quickly becoming a reality, actual testing time with visual prosthesis carriers is at a premium. Moreover, it is helpful to have a more realistic functional approximation of a blind subject. Instead of a normal subject with a healthy retina looking at a low-resolution (pixelated) image on a computer monitor or head-mounted display, a more realistic approximation is achieved by employing a subject-independent mobile robotic platform that uses a pixelated view as its sole visual input for navigation purposes. We introduce CYCLOPS: an AWD, remote controllable, mobile robotic platform that serves as a testbed for real-time image processing and autonomous navigation systems for the purpose of enhancing the visual experience afforded by visual prosthesis carriers. Complete with wireless Internet connectivity and a fully articulated digital camera with wireless video link, CYCLOPS supports both interactive tele-commanding via joystick, and autonomous self-commanding. Due to its onboard computing capabilities and extended battery life, CYCLOPS can perform complex and numerically intensive calculations, such as image processing and autonomous navigation algorithms, in addition to interfacing to additional sensors. Its Internet connectivity renders CYCLOPS a worldwide accessible testbed for researchers in the field of artificial vision systems. CYCLOPS enables subject-independent evaluation and validation of image processing and autonomous navigation systems with respect to the utility and efficiency of supporting and enhancing visual prostheses, while potentially reducing to a necessary minimum the need for valuable testing time with actual visual prosthesis carriers.

[Management of cutaneous toxicities induced by epidermal growth factor receptor inhibitors: a review]

The epidermal growth factor receptor (EGFR) is overexpressed in many solid tumors. Its inactivation has an inhibitory effect on the growth and spread of the tumoral cells. It therefore represents an attractive target to treat different cancers. Several molecules have already been registered while others are still under evaluation. One of the common side effects of these therapies is the development of cutaneous toxicities, more precisely a cutaneous rash, sometimes major and distressing. The physiopathology of these cutaneous side effects is poorly understood. Moreover a correlation between the severity of the rash and the tumoral response has been demonstrated in some studies. If this link is confirmed, the rash could be used as a marker for the anti-tumoral activity. This review will summarize the clinical presentations and the current recommendations for the management of cutaneous toxicities induced by EGFR inhibitors.

Early detection of glaucoma by means of a novel 3D computer-automated visual field test

PURPOSE

A recently devised 3D computer-automated threshold Amsler grid test was used to identify early and distinctive defects in people with suspected glaucoma. Further, the location, shape and depth of these field defects were characterised. Finally, the visual fields were compared with those obtained by standard automated perimetry.

PATIENTS AND METHODS

Glaucoma suspects were defined as those having elevated intraocular pressure (>21 mm Hg) or cup-to-disc ratio of >0.5. 33 patients and 66 eyes with risk factors for glaucoma were examined. 15 patients and 23 eyes with no risk factors were tested as controls. The recently developed 3D computer-automated threshold Amsler grid test was used. The test exhibits a grid on a computer screen at a preselected greyscale and angular resolution, and allows patients to trace those areas on the grid that are missing in their visual field using a touch screen. The 5-minute test required that the patients repeatedly outline scotomas on a touch screen with varied displays of contrast while maintaining their gaze on a central fixation marker. A 3D depiction of the visual field defects was then obtained that was further characterised by the location, shape and depth of the scotomas. The exam was repeated three times per eye. The results were compared to Humphrey visual field tests (ie, achromatic standard or SITA standard 30-2 or 24-2).

RESULTS

In this pilot study 79% of the eyes tested in the glaucoma-suspect group repeatedly demonstrated visual field loss with the 3D perimetry. The 3D depictions of visual field loss associated with these risk factors were all characteristic of or compatible with glaucoma. 71% of the eyes demonstrated arcuate defects or a nasal step. Constricted visual fields were shown in 29% of the eyes. No visual field changes were detected in the control group.

CONCLUSIONS

The 3D computer-automated threshold Amsler grid test may demonstrate visual field abnormalities characteristic of glaucoma in glaucoma suspects with normal achromatic Humphrey visual field testing. This test may be used as a screening tool for the early detection of glaucoma.

Progress towards a high-resolution retinal prosthesis

Simulations of artificial vision suggest that 1000 electrodes may be required to restore vision to individuals with diseases of the outer retina. In order to achieve such an implant, new technology is needed, since the state-of-the-art implantable neural stimulator has at most 22 contacts with neural tissue. Considerable progress has been made towards that goal with the development of image processing, microelectronics, and polymer based electrodes and interconnects. An image processing system has been realized that is capable of real-time implementation of image decimation and filtering (for example, edge detection). Application specific integrated circuits (ASICs) have been designed and tested to demonstrate closed loop power control and efficient microstimulation. A novel packaging process has been developed that is capable of simultaneously forming a receiver coil, interconnects, and stimulating electrodes.

Snapshot hyperspectral imaging in ophthalmology

Retinal imaging spectroscopy can provide functional maps using chromophore spectra. For example, oxygen saturation maps show ischemic areas from diabetes and venous occlusions. Obtaining retinal spatial-spectral data has been difficult due to saccades and long data acquisition times (>5 s). We present a snapshot imaging spectrometer with far-reaching applicability that acquires a complete spatial-spectral image cube in approximately 3 ms from 450 to 700 nm with 50 bands, eliminating motion artifacts and pixel misregistration. Current retinal spectral imaging approaches are incapable of true snapshot operation over a wide spectral range with a large number of spectral bands. Coupled to a fundus camera, the instrument returns true color retinal images for comparison to standard fundus images and for image validation while the patient is still dilated. Oxygen saturation maps were obtained with a three-wavelength algorithm: for healthy subjects arteries were approximately 95% and veins 30 to 35% less. The instrument is now undergoing clinical trials.

simEye: Computer-based simulation of visual perception under various eye defects using Zernike polynomials

We describe a computer eye model that allows for aspheric surfaces and a three-dimensional computer-based ray-tracing technique to simulate optical properties of the human eye and visual perception under various eye defects. Eye surfaces, such as the cornea, eye lens, and retina, are modeled or approximated by a set of Zernike polynomials that are fitted to input data for the respective surfaces. A ray-tracing procedure propagates light rays using Snell's law of refraction from an input object (e.g., digital image) through the eye under investigation (i.e., eye with defects to be modeled) to form a retinal image that is upside down and left-right inverted. To obtain a first-order realistic visual perception without having to model or simulate the retina and the visual cortex, this retinal image is then back-propagated through an emmetropic eye (e.g., Gullstrand exact schematic eye model with no additional eye defects) to an output screen of the same dimensions and at the same distance from the eye as the input object. Visual perception under instances of emmetropia, regular astigmatism, irregular astigmatism, and (central symmetric) keratoconus is simulated and depicted. In addition to still images, the computer ray-tracing tool presented here (simEye) permits the production of animated movies. These developments may have scientific and educational value. This tool may facilitate the education and training of both the public, for example, patients before undergoing eye surgery, and those in the medical field, such as students and professionals. Moreover, simEye may be used as a scientific research tool to investigate optical lens systems in general and the visual perception under a variety of eye conditions and surgical procedures such as cataract surgery and laser assisted in situ keratomileusis (LASIK) in particular.

Venus, Mars, and the ices on Mercury and the moon: astrobiological implications and proposed mission designs

Venus and Mars likely had liquid water bodies on their surface early in the Solar System history. The surfaces of Venus and Mars are presently not a suitable habitat for life, but reservoirs of liquid water remain in the atmosphere of Venus and the subsurface of Mars, and with it also the possibility of microbial life. Microbial organisms may have adapted to live in these ecological niches by the evolutionary force of directional selection. Missions to our neighboring planets should therefore be planned to explore these potentially life-containing refuges and return samples for analysis. Sample return missions should also include ice samples from Mercury and the Moon, which may contain information about the biogenic material that catalyzed the early evolution of life on Earth (or elsewhere). To obtain such information, science-driven exploration is necessary through varying degrees of mission operation autonomy. A hierarchical mission design is envisioned that includes spaceborne (orbital), atmosphere (airborne), surface (mobile such as rover and stationary such as lander or sensor), and subsurface (e.g., ground-penetrating radar, drilling, etc.) agents working in concert to allow for sufficient mission safety and redundancy, to perform extensive and challenging reconnaissance, and to lead to a thorough search for evidence of life and habitability.

SCOTOMAS OF AGE-RELATED MACULAR DEGENERATION DETECTED AND CHARACTERIZED BY MEANS OF A NOVEL THREE-DIMENSIONAL COMPUTER-AUTOMATED VISUAL FIELD TEST

PURPOSE

We used the recently devised three-dimensional computer-based threshold Amsler grid test to acquire and identify typical patterns of visual field defects (scotomas) caused by age-related macular degeneration (AMD).

METHODS

Patients with AMD traced on a computer touch screen the borders of those areas on an Amsler grid that were missing from their field of vision. Scotomas were repeatedly outlined and recorded at different grid contrast levels. The resulting three-dimensional "hole" in the central 25 degrees of the visual field was further characterized by its slope, location, shape, and depth. The results were compared with fundus photographs and fluorescein angiograms.

RESULTS

Twenty-five patients and 41 eyes were examined. The three-dimensional depictions consistently demonstrated central scotomas with "scallop"-shaped borders and steplike patterns, with either steep slopes or a combination of steep and shallow slopes. The steep slopes corresponded to nonexudative AMD, while the shallow slopes indicated exudative AMD.

CONCLUSION

The three-dimensional computer-automated threshold Amsler grid test may demonstrate characteristic scotoma patterns in patients with AMD that conform to the respective fluorescein angiograms. The test shows promise as an effective tool in accurately evaluating, characterizing, and monitoring scotomas in patients with AMD. It may have the potential as a screening tool for the early diagnosis of AMD.

Refractive correction method for digital charge-coupled device-recorded Scheimpflug photographs by means of ray tracing

Our purpose is to correct digital CCD-recorded Scheimpflug photographs, imaging both the anterior and posterior corneal surface, the anterior chamber, and the anterior eye lens surface for optical distortions. In a ray-tracing algorithm the imaging of the posterior corneal surface in a given Scheimpflug photograph is corrected by applying Snell's law on parallel incident rays entering through the anterior corneal surface. Once the posterior corneal surface is corrected, the procedure is repeated, again with parallel incident rays entering through both the anterior and now corrected posterior corneal surface, to correct the imaging of the anterior eye lens surface. The refractive indices necessary for Snell's law are taken from Gullstrand's exact schematic eye model. Due to the optical/refractive correction, the digital Scheimpflug photograph decreases in size perpendicular to the direction of the optical axis. As a consequence the curvature radii of both the posterior corneal surface and the anterior lens surface are reduced significantly, as compared to the original digital Scheimpflug photograph. Furthermore, the corneal thickness and the anterior chamber depth are increased. The presented refractive correction method enables us to extract from Scheimpflug photographs the following quantities rather realistically: structure coordinates and curvature radii of both the posterior corneal surface and the anterior lens surface, corneal thickness, and anterior chamber depth. This method can readily be applied to other imaged quantities, such as the posterior eye lens surface, the lens thickness, and the pupillary opening.

Clinical phase II study of pegylated liposomal doxorubicin as second-line treatment in disseminated melanoma

BACKGROUND

Stage IV melanoma has a poor prognosis with a median survival of 3-11 months from diagnosis of distant metastases. Response rates in first-line regimens range around 15-20%. Non-responders have a median survival around 6 months. Currently, no second-line treatment in advanced melanoma has been established.

PATIENTS AND METHODS

In a clinical phase II study we evaluated the efficacy of liposomal doxorubicin (Caelyx) in 30 patients (17 m, 13 f) with progressing metastatic melanoma who had failed a previous chemotherapy. Liposomal doxorubicin was given in an outpatient setting at a dose of 50 mg/m2 i.v. on d1, d22, d43 and d64, subsequently at 40 mg/m2 at d85 before first staging and in 4-week intervals thereafter. Treatment was very well tolerated with 100 cycles given in total. Response rate, survival time, time-to-progression and toxicity were assessed.

RESULTS

Erythrodysesthesia was the most severe toxicity in 6% at CTC grade 3. Liposomal doxorubicin was of limited clinical efficacy with 21 patients progressing within the first 12 weeks. However, 7 patients were treated 3-9 months and were stable for >90 days, achieving 5 SD, 1 PR and 1 CR. Median survival after initiation of second-line treatment was 214 days (95% CI: 151-304 days) with 7 patients surviving >300 and 5 patients >400 days.

CONCLUSIONS

Liposomal doxorubin as monotherapy is well tolerated but of limited clinical efficacy. Whether the survival benefit of a significant proportion of patients (20%) holds true in larger cohorts and whether the efficacy of liposomal doxorubicin can be improved by combinations without compromising the low toxicity profile needs further studies.

Neural attractor network for application in visual field data classification

The purpose was to introduce a novel method for computer-based classification of visual field data derived from perimetric examination, that may act as a 'counsellor', providing an independent 'second opinion' to the diagnosing physician. The classification system consists of a Hopfield-type neural attractor network that obtains its input data from perimetric examination results. An iterative relaxation process determines the states of the neurons dynamically. Therefore, even 'noisy' perimetric output, e.g., early stages of a disease, may eventually be classified correctly according to the predefined idealized visual field defect (scotoma) patterns, stored as attractors of the network, that are found with diseases of the eye, optic nerve and the central nervous system. Preliminary tests of the classification system on real visual field data derived from perimetric examinations have shown a classification success of over 80%. Some of the main advantages of the Hopfield-attractor-network-based approach over feed-forward type neural networks are: (1) network architecture is defined by the classification problem; (2) no training is required to determine the neural coupling strengths; (3) assignment of an auto-diagnosis confidence level is possible by means of an overlap parameter and the Hamming distance. In conclusion, the novel method for computer-based classification of visual field data, presented here, furnishes a valuable first overview and an independent 'second opinion' in judging perimetric examination results, pointing towards a final diagnosis by a physician. It should not be considered a substitute for the diagnosing physician. Thanks to the worldwide accessibility of the Internet, the classification system offers a promising perspective towards modern computer-assisted diagnosis in both medicine and tele-medicine, for example and in particular, with respect to non-ophthalmic clinics or in communities where perimetric expertise is not readily available.

Three-dimensional computer-automated threshold Amsler grid test

We describe a novel method for testing a visual field that employs a computer monitor with displays of varying contrast that permits unprecedented resolution and characterization of the structure of scotomas in three dimensions. Patients are placed in front of a touch-sensitive computer screen at a fixed distance. With one eye covered, they focus on a central fixation marker and trace with their finger the areas on an Amsler grid that are missing from their field of vision. Increasing degrees of contrast of the Amsler grid are simulated by repeating the test at different gray-scale levels. The results are recorded and then displayed as topographical contour rings by the computer test program. The results can also be rendered as an immediate 3-D depiction of the central hill-of-vision. Several clinical pilot studies have been conducted at the Doheny Eye Institute and more than 200 patients have been examined with this system so far. Conditions such as optic neuritis, anterior ischemic optic neuropathy (AION), age-related macular degeneration (AMD), glaucoma, and ocular hypertension have been successfully assessed by this test. Each condition provides unique patterns that are most evident in 3-D. The 3-D computer-automated threshold Amsler grid test is an innovative and noninvasive visual field test. It provides several advantages over state-of-the-art standard automated perimetry, including: (1) additional information through 3-D depiction of scotomas, such as location, extent, slope, depth, and shape; (2) high angular resolution (1 deg compared with typically 6 deg); (3) a simple test setup (merely a touch-sensitive computer monitor and the test software); (4) excellent patient compliance (spending 4 to 5 min per eye). In light of its promising initial tests, the 3-D visual field test appears to have the potential for the early detection and monitoring of various diseases over time.

Mucosal metastases in malignant melanoma

BACKGROUND

We present the case of a patient with malignant melanoma stage IV according to the American Joint Committee on Cancer (AJCC) classification and an unusual pattern of metastasis to the mucosa of the esophagus, the stomach, the bladder and the palatine tonsil.

CASE REPORT

A 38-year-old male patient with metastatic malignant melanoma of stage III (AJCC) was admitted for initiation of adjuvant therapy. 4 months earlier a primary melanoma of the left upper leg had been excised and 2 months later the patient had undergone a left inguinal lymph node dissection revealing 2 metastatic lymph nodes. On admission the patient complained of a sore throat and right cervical lymphadenopathy. He underwent a tonsillectomy and a lymphadenectomy which both revealed melanoma metastases. A PET scan using F-18-fluorodeoxyglucose (FDG) showed focal metabolic activity in the middle mediastinum. Two cycles of dacarbazine (DTIC) chemotherapy were performed during which the patient developed cutaneous metastases, dyspepsia, and mild hematemesis. Gastroscopy revealed bleeding from mucosal metastases of the esophagus and stomach. A few weeks later the patient developed macroscopic hematuria. A cystoscopy was performed and showed metastases to the mucosa of the bladder. Nutrient vessels of these bladder metastases were embolized in order to control bleeding. The patient is currently alive with progressive disease.

RESULTS

This case presents common and uncommon sites of metastatic melanoma to the mucosa with the typical clinical manifestations in a single patient.

[Renaissance of general practice]

Special research work has taught that general practice (family medicine) is a specialization of its own. It requires specific education and vocational training. As far as universities and administrative bodies have accepted it no doctor can start practising family medicine unless he has passed a vocational training of many years duration. That fact together with a successful continued research concerning applied general practice should initiate a true renaissance of general practice.

Beam-deflection method of diagnosing impaired vision

We describe a simple method to assign a diagnosis of cataract to patients with obscurely impaired vision as well as to those with mild lens opacities. When the narrowest slit is used in a slitlamp examination, a small beam of light appears on the macula. Routine fundoscopy with the 78.0 diopter lens or a 3-mirror glass is appropriate. If a cataract is present, the beam of light is scattered into several straight lines, distorted lines, or both. This has proved a useful diagnostic tool when the lens appears clear but the patient's vision is impaired, and extensive examinations such as computer tomography or nuclear magnetic resonance tomography for impaired vision may be avoided. The beam-deflection method uses devices that are generally available and can detect cataract in the early stages of development.

Efficacy of mifepristone followed on the same day by misoprostol for early termination of pregnancy: report of a randomised trial

OBJECTIVE

To examine the clinical efficacy of mifepristone 600 mg followed on the same day or two days later by misoprostol 400 microg orally in women undergoing medical termination of pregnancy whose pregnancies have a gestational age up to 49 days.

DESIGN

Prospective, randomised trial.

SETTING

Clinical research office.

PARTICIPANTS

Eighty-six women, requesting elective termination of a pregnancy which has a gestational age of < or = 49 days.

METHODS

After administration of mifepristone 600 mg, participants were randomised to take misoprostol six to eight hours later (Group 1) or 48 hours later (Group 2). Women returned for a follow up evaluation 24 +/- 1 hours after taking the misoprostol. Participants in Group 1 who had not aborted received a second dose of misoprostol to take 48 hours after the mifepristone. All women returned approximately two weeks after receiving mifepristone. If termination of pregnancy had still not occurred and the pregnancy was non-viable, the woman returned again in three weeks.

MAIN OUTCOME MEASURES

Rate of complete abortion 24 hours after administration of misoprostol.

RESULTS

At 24 hours after receiving misoprostol, 21/42 (50%, 95% CI 35%, 65%) women in Group I and 40/44 (91%, 95% CI 82%, 99%) women in Group 2 had complete abortions. By follow up two weeks later after the administration of mifepristone, 40/42 (95%, 95% CI 89%, 100%) women in Group 1 and 43/44 (98%, 95% CI 93%, 99%) women in Group 2 were known to have complete abortions. Nausea, vomiting or diarrhoea in women using the standard regimen (Group 2) occurred in 68%, 36%, and 20%, respectively.

CONCLUSIONS

After treatment with mifepristone 600 mg, administration of misoprostol 400 microg orally on the same day is not as effective at causing abortion within the first 24 hours compared with the standard time interval of 48 hours between medications.

Scheimpflug records without distortion--a mythos?

The Scheimpflug principle was recommended as allowing distortion-free imaging; however, a detailed analysis reveals geometrical errors as well as distortions arising from absorption of light along the optical pathway. Correction formulas and factors will be presented and applied to the biometry of the eye.

Immunohistochemical and molecular characterization of cultured keratinocytes after dispase-mediated detachment from the growth substratum

Keratinocyte activation comprises changes in protein and gene expression pattern resulting in phenotypic and functional changes necessary for re-epithelialization such as the expression of urokinase-type plasminogen activator (uPA) and its cell surface receptor (uPA-R; CD87). As uPA and uPA-R are rapidly induced after dispase-mediated detachment of cultured normal human epidermal keratinocytes (NHEK) we hypothesized that dispase-mediated detachment may cause a similar "activation" of keratinocytes with uPA and uPA-R being only one aspect of a complex "activation reaction". To test this hypothesis we have comparatively analysed adherent versus detached keratinocyte sheets for selected indicators of keratinocyte activation by immunohistochemistry. Furthermore we have identified genes via subtraction cloning which are up-regulated upon dispase-induced detachment. The analyses provided evidence for an increased transcriptional and translational activity in detached keratinocytes, as indicated by over-expression of several ribosomal components (L3 and S10 ribosomal protein) and transcription factors (initiation factor 4A, elongation factor 1alpha). Increased proliferative activity was indicated by increased expression of the proliferation markers Ki67, keratin 6 and keratin 17. Finally, several markers of keratinocyte activation such as the integrin chain alpha(v), psoriasin, glutathion-S-transferase and heparin-binding epidermal growth factor-like growth factor were up-regulated. Furthermore mevalonate kinase, a molecule as yet unknown to be expressed in keratinocytes, was identified. The findings provide evidence that dispase-mediated detachment in cultured keratinocytes induces a reaction, which comprises the up-regulation of a complex array of proliferation- and migration-related molecules. The pattern of which resembles the activation reaction observed in the re-epithelializing keratinocytes in vivo.

Electronic Structure of the Aqueous Vanadyl Ion Probed by 9 and 94 GHz EPR and Pulsed ENDOR Spectroscopies and Density Functional Theory Calculations

The aqueous vanadyl ion ([VO(H(2)O)(5)](2+)) has been investigated by X-band EPR, 94 GHz W-band EPR, and ESE-ENDOR. These experiments reveal information about the hyperfine (|A(xx)| = 208.5 MHz, |A(yy)| = 208.5 MHz, |A(zz)| = 547.0 MHz), and nuclear quadrupole coupling (|e(2)qQ| = 5.6 MHz) of the (51)V nucleus. The measured nuclear quadrupole coupling parameters are compared to values determined by density functional theory calculations (|e(2)qQ| = 5.2 MHz). These theoretical calculations illustrate that axial ligands and molecular distortions can alter the magnitude of the nuclear quadrupole interaction.

[Axial displacement of IOL and visual impairment]

BACKGROUND

After a cataract surgery procedure with vitreous loss a vitreous strand remained in the wound. An unusual visual impairment was observed.

PATIENT

A shift in refraction depending on the pupillary diameter was observed. In miosis the refraction was estimated to +1.0 sph, in mydriasis -1.0 sph/ -0.5 cyl, respectively.

METHOD

We presumed that the vitreous strand between the iris and the intraocular lens caused an axial displacement of the IOL during the change from miosis to mydriasis and v.v. Therefore the vitreous strand was surgically eliminated. After surgery the refractive changes by pupillary actions were overcome. In a computer simulation (ray tracing), the amount of axial displacement of the IOL was estimated to 1.5 mm.

CONCLUSION

This paper reminds of considering other reasons for loss of VA than CME, e.g. axial displacement of IOL. An adequate method of examination is the measurement of refraction in miosis and mydriasis.

[R. N. Braun diagnostic programs: what prevents the general practitioner from using them? Results of a 1-year-study of indications, acceptance and failure to apply diagnostic programs]

In General Practice, a global measure for quality control has not yet been established. Procedures in this field of health care are usually not evidence based but rely on personal experience. In 1976, the "Diagnostic Protocols" (DP) had been introduced by Robert N. Braun to cover the most frequent and most important uncharacteristic complaints presented to the General Practitioner by the patient. In this study, the authors are showing how often the usage of DP may be useful in the management of cases in General Practice. Additionally, reasons are demonstrated that may lead the Family Physician not to apply DP in certain cases. In 2,084 new cases presented to a General Practitioner within one year (1-12/1994), 19 of 82 existing protocols were used. In every sixth new case (16%), the patient's history and physical examination were analyzed with the help of Diagnostic Protocols. However, their usage would have been beneficial in one of four cases (24.6%). Reasons for declining DP included "No need for further diagnostic investigation" and "Other diagnostic strategy chosen". Shortness of time only played a minor role.

[Visual image in high ametropia. Computer-assisted simulation with optic ray calculation]

PURPOSE

A computer program developed by the authors allows to calculate the path of light rays coming from an object through all the refractive surfaces of a Gullstrand model eye until it reaches the retina.

METHOD

The program calculates several hundred light rays for every point of a given object. A menue allows to modify optical and morphological parameters in an interactive way. For instance, the indices of refraction, the radii of the cornea and of the cristalline lens, as well as the length of the bulbus can be modified. Further, one can add seeing aids such as eye glasses or a contact lens, or implant an artificial intraocular lens. The seeing aids may be decentered and/or tilted.

RESULTS

The code calculates also the visual impression by projecting the image from the retina back to a screen at the distance of the object, where the human brain "sees" the object. For image interpretation we use a normal Gullstrand eye with a very small aperture stop. In this way we can simulate the visual mapping (visual impression) of a corrected or uncorrected ametropia.

CONCLUSIONS

In this paper we present two nontrivial examples: we calculate the regional polyopia ("Bildverdoppelung") and the annular scotoma which appear whenever a high myopia or aphakia are corrected by eye glasses.

Multi-layered perceptron as a model for the pupillary pathway

Derived from models of neural networks, a model for the pupillary pathway is introduced that can easily be handled computationally and analytically. To model the binocular pupillary reactions we use a feed-forward network, namely, a multi-layered perception. It is possible to calculate the pupillary reactions analytically as a function of the light stimuli of the retinal hemifields, on the one hand, and the set of neural couplings between the neural layers, on the other. Several lesions, e.g., lesions of the intercalated neurons between the afferent and efferent pupillary pathways, can be simulated within the model and the corresponding pupillary reactions such as anisocoria or relative afferent pupillary defects (RAPD) can be calculated analytically. Due to its neural network structure the model described herein can easily be extended to much more complex pupillary pathways while remaining calculable computationally and analytically.