Digitized mini optofluidic element and its application to ophthalmic lenses for presbyopia correction.

Using the internally placed elastic membrane and multi-chamber configuration, we designed a digitized mini optofluidic element for fast switching between refractive and diffractive states of preset optical powers. Relief surface was used in the diffractive state. We applied finite element analysis to establish membrane mechanical characteristics for switching at the force level produced by the ocular elements such as ciliary muscle or lower eyelid at eye downgaze. The prototypes were made to demonstrate proof-of-concept. Membrane conformance to the diffractive grooves and imaging quality were demonstrated. The analysis supported switching under the force level exerted by the ocular elements supporting the digitized optofluidic element potential for presbyopia correction by ophthalmic lenses.

A haemodynamic study during OPCAB surgery using a new multi-suction cardiac positioner.

BACKGROUND: Displacement of the heart is necessary to expose the target vessel for distal anastomosis to achieve successful multivessel off-pump coronary artery bypass (OPCAB) grafting. In addition to complete revascularisation of the heart, a main challenge during the operation is to maintain haemodynamic stability during this procedure. A new heart positioner (Tentacles) was tested. METHODS: In a prospective clinical study we used the Tentacles device in 50 patients scheduled for multivessel OPCAB procedures and investigated the haemodynamic effects during displacement of the heart and while performing the anastomoses to the anterior, lateral and posterior wall. The following haemodynamic parameters were investigated: mean arterial blood pressure (MAP), cardiac index (CI) and stroke volume index (SVI). The incidence of myocardial ischaemia was monitored by transoesophageal echocardiography (TEE) and by ST-segment analysis in the electrocardiogram (ECG). RESULT: The Tentacles device permitted rapid, secure and excellent exposure of the lateral and posterior wall of the heart. During exposure of the anterior wall there was a small decrease in MAP (77 ± 10 vs.71 ± 9 mmHg, P = 0.02) in combination with an increase in the CI (3.0 ± 0.7 l vs. 3.1 ± 0.8 l/min/m2, P = 0.03). When the lateral and posterior walls of the heart were exposed, the SVI decreased significantly (36 ± 11 and 38 ± 8 mL/m2, P < 0.01 and P = 0.04, respectively) compared to baseline (44 ± 11 mL/m2) while CI and MAP remained stable. The amount of norepinephrine administered during displacement of the heart was significantly higher in all three positions (0.05 ± 0.05, 0.06 ± 0.05 and 0.04 ± 0.03 µg/kg/min, P < 0.01) compared to the physiological position (0.02 ± 0.02 µg/kg/min). Sinus rhythm was maintained throughout the operation. Neither significant changes of the ST-segment in the ECG nor incidences of wall motion abnormality in TEE were observed. Six hours postoperatively the troponin I concentration was 11.7 ± 4.3 ng/mL. CONCLUSION: The Tentacles device provided excellent access in multivessel OPCAB surgery. Haemodynamic stability was maintained in all patients; however additional catecholamine support was used when the heart was displaced. This was the case when carrying out an anastomosis on the anterior, lateral, or posterior wall.

On the cell biology of HIV integration from basic research to development of novel antiviral drugs.

Viruses in general, HIV in particular, use cellular proteins or cofactors to achieve their replication cycle. Our recent research efforts resulted in the identification and validation of two new cellular cofactors of HIV replication: LEDGF/p75 and transportin-SR2. LEDGF/p75 is a cellular transcriptional coactivator used by the virus to tether the preintegration complex onto the chromosome; transportin-SR2 is a cellular import factor used by the virus for nuclear import into the nucleus. After validation of LEDGF/p75 as an antiviral target, we initiated a drug discovery program to develop small molecule inhibitors of integrase-LEDGF/p75 interaction. Using molecular modeling, medicinal chemistry, crystallography and virology, our team developed LEDGINs, the first-in-class small molecule inhibitors of HIV targeting integrase/LEDGF/p75 interaction. As for transportin-SR2, this protein was identified by yeast-two-hybrid screening and validated as a nuclear import factor for HIV. A drug discovery program for inhibitors of nuclear import is ongoing. Together our research results provide a paradigm shift in antiviral research. Yes, small molecules can be developed inhibiting the protein-protein interaction between a viral protein and a cellular cofactor. In a broader perspective our research strongly supports the development of protein-protein interaction inhibitors as drugs.

Microvascular perfusion measured by orthogonal polarization spectral imaging is well maintained during exposure to high altitude in trained mountaineers.

The objective of this study was to examine microvascular perfusion during hypobaric hypoxia and physical exercise. We used orthogonal polarization spectral imaging for the non-invasive visualization and assessment of the sublingual mucosal microcirculation in twelve healthy altitude acclimatized mountaineers. Red blood cell velocity (RCV), microvascular diameter (Dia), functional capillary density (FCD) and the number of rolling leukocytes were studied at baseline and after (I) a climb to an altitude of 3196 m, (II) a passive ascent to the same altitude by helicopter and (III) an exercise program at an altitude below 2100 m in the European Alps. Exposure to high altitude and exercise resulted in an increased heart rate (Trial I: 64 (54-66) vs. 95 (84-100); median (interquartile range); P<0.05) and decreased oxygen saturation (Trial I: 98 (98-99) vs. 90 (88-92); P<0.05). However, RCV, Dia and FCD did not change significantly. Furthermore, no enhanced rolling of leukocytes in postcapillary venules could be observed (Trial I: 6.2 (4.4-6.8) vs. 7.8 (4.3-6.7)). In the pooled data of all three trials of this study we could show a significant positive correlation between oxygen saturation and red blood cell velocity (r = 0.25; P = 0.02). These results indicate that orthogonal polarization spectral imaging can be a useful tool for the microcirculatory assessment of man under hypoxic conditions. We could show that in trained, acclimatized subjects microvascular perfusion is well maintained during hypobaric hypoxia at an altitude of 3196 m and no evidence for an increased postcapillary leukocyte adhesion was seen.

A model for the PI-SceIxDNA complex based on multiple base and phosphate backbone-specific photocross-links.

We have synthesized different oligodeoxynucleotides carrying, in single positions of the >36 bp recognition site of PI-SceI, photoreactive base analogues (5-iododeoxypyrimidines) or phosphate modifications (p-azidophenacylphosphorothioates) and used them in photocross-linking experiments with PI-SceI to probe the protein-DNA interface of the specific complex between the homing endonuclease PI-SceI and its DNA substrate. One base-specific and several backbone-specific cross-links were analyzed in detail: the cross-linking positions were identified by Edman degradation of isolated cross-linked peptidexoligodeoxynucleotide adducts and confirmed by site-directed mutagenesis. Based on these results and the crystal structure of PI-SceI, a model for the structure of the PI-SceIxDNA complex is proposed.

Cell type-specific Nogo-A gene ablation promotes axonal regeneration in the injured adult optic nerve.

Nogo-A is a well-known myelin-enriched inhibitory protein for axonal growth and regeneration in the central nervous system (CNS). Besides oligodendrocytes, our previous data revealed that Nogo-A is also expressed in subpopulations of neurons including retinal ganglion cells, in which it can have a positive role in the neuronal growth response after injury, through an unclear mechanism. In the present study, we analyzed the opposite roles of glial versus neuronal Nogo-A in the injured visual system. To this aim, we created oligodendrocyte (Cnp-Cre(+/-)xRtn4/Nogo-A(flox/flox)) and neuron-specific (Thy1-Cre(tg+)xRtn4(flox/flox)) conditional Nogo-A knock-out (KO) mouse lines. Following complete intraorbital optic nerve crush, both spontaneous and inflammation-mediated axonal outgrowth was increased in the optic nerves of the glia-specific Nogo-A KO mice. In contrast, neuron-specific deletion of Nogo-A in a KO mouse line or after acute gene recombination in retinal ganglion cells mediated by adeno-associated virus serotype 2.Cre virus injection in Rtn4(flox/flox) animals decreased axon sprouting in the injured optic nerve. These results therefore show that selective ablation of Nogo-A in oligodendrocytes and myelin in the optic nerve is more effective at enhancing regrowth of injured axons than what has previously been observed in conventional, complete Nogo-A KO mice. Our data also suggest that neuronal Nogo-A in retinal ganglion cells could participate in enhancing axonal sprouting, possibly by cis-interaction with Nogo receptors at the cell membrane that may counteract trans-Nogo-A signaling. We propose that inactivating Nogo-A in glia while preserving neuronal Nogo-A expression may be a successful strategy to promote axonal regeneration in the CNS.

Increased microvascular water permeability in patients with septic shock, assessed with venous congestion plethysmography (VCP).

OBJECTIVES: To investigate microvascular water permeability (filtration capacity, Kf) in patients with septic and non-septic shock using a new non-invasive method for studying microvascular parameters in man. SETTING: Intensive Care Unit of a university hospital. PATIENTS AND METHODS: We investigated 28 patients, presenting with cardio-vascular instability due to either septic shock, or non-septic shock (haemorrhage, multiple trauma, respiratory and/or cardiac failure). INTERVENTIONS: We used standard invasive methods of monitoring (in-dwelling arterial lines and pulmonary artery flotation catheters) in combination with computer assisted venous congestion plethysmography (VCP) measurements, for a parallel assessment of peripheral microcirculatory parameters. RESULTS: On admission to the ICU, patients with septic shock revealed a significantly higher mean value of filtration capacity Kf = 6.1 +/- 0.4 x 10(-3) (mean value +/- standard error of the mean, ml.min-1.100 ml tissue-1.mmHg-1 = KfU) than non-septic patients Kf = 3.5 +/- 0.3 KfU (p < 0.02). The Kf values of the septic patients were significantly higher than those from age-matched patients with peripheral vascular disease (4.1 +/- 0.2 KfU, p < 0.001) and those of healthy controls (4.3 +/- 0.2 KfU, p < 0.001); the Kf values of the non-septic patients, however, were not significantly different. The highest mean Kf value observed during the stay on ICU was Kfmax 11.6 +/- 0.2 KfU in the septic group and 5.7 +/- 0.1 KfU in the non-septic group (p < 0.001). Pvi, a value reflecting the balance of hydrostatic and oncotic forces in the microcirculation, was elevated in both patient groups. On admission, in septic patients Pvi was 39.2 +/- 3.3 mmHg and in non-septic patients 35.1 +/- 2.7 mmHg, these values were not significantly different, but significantly higher than the Pvi value of healthy controls (Pvi 21.5 +/- 0.8) (p < 0.001). A weak, however significant, positive correlation was found between Kf and Pvi in both patient groups. No correlations were found between Kf, as well as Pvi, and cardiac index (CI), oxygen delivery index (DO2I), oxygen consumption index (VO2I) and systemic vascular resistance index (SVRI). CONCLUSIONS: An increase in permeability of microvessels will cause a loss of intravascular fluid and may therefore partially explain the large fluid requirements of patients in shock. It will also favour the development of oedema, which is often found in septic patients. We propose that changes in Kf are useful indices of microvascular malfunction and that VCP allows the non-invasive assessment of these parameters.

Simulated microgravity, psychic stress, and immune cells in men: observations during 120-day 6 degrees HDT.

Because 6 degrees head-down tilt (HDT) is an established method to mimic low gravity on earth, the aim of the present study was to determine the effects of 120-day HDT on psychic stress and peripheral blood immune cells in six healthy male volunteers. Psychological state was assessed by a current stress test, and cortisol was measured in saliva. During HDT, all volunteers developed psychic stress, and the diurnal rhythm of cortisol secretion was significantly altered. In addition, urine excretion of dopamine and norepinephrine increased. The innate part of the immune response was activated, as evidenced by the increase in the expression of beta(2)-integrins on polymorphonuclear leukocytes and a rise in the number of circulating natural killer (NK) cell lymphocytes. The ratio of T-helper to T-cytotoxic and T-suppressor cells decreased, whereas no changes in T and B lymphocytes were observed. Plasma levels of interleukin-6 increased significantly and returned to basal levels after the end of the HDT period. Thus 6 degrees HDT appears to be a valid model to induce psychic stress and neuroendocrine-related changes in the immune system, changes that might also be encountered by astronauts and cosmonauts during long-duration spaceflights.

Description and validation of a novel liquid metal-free device for venous congestion plethysmography.

We present a newly developed electromechanical sensor with automated calibration for strain-gauge plethysmography (filtrass) and compare it to a conventional mercury-in-Silastic strain-gauge plethysmograph (MSG). Fluid filtration capacity (K(f)) and isovolumetric venous pressure (Piv) of the limb were assessed noninvasively with both devices in 29 healthy volunteers. We found significantly higher K(f) and Piv values with MSG [4.6 +/- 2.0 x 10(-3) ml. min(-1). mmHg(-1). 100 ml tissue(-1) (K(f) units; K(f)U) and 21.2 +/- 8.1 mmHg for Pvi], than with filtrass, giving values of 3.1 +/- 0.8 K(f)U and 15.1 +/- 7.1 mmHg. Because K(f) and Piv are profoundly influenced by the calibration, we investigated the quality of the calibration signal and its impact on the obtained values. We could show that the reproducibility of repeated calibrations was higher with filtrass (58% lower mean +/- SD). The data were grouped according to the quality of calibration, and we found no significant difference in K(f) and Piv between filtrass (3.0 +/- 0.7 K(f)U and 15.9 +/- 6.9 mmHg, respectively) and MSG with good calibration signal (3.3 +/- 0. 8 K(f)U and 18.6 +/- 7.1 mmHg, respectively; no significant difference). However, we obtained significantly higher MSG values (5. 6 +/- 2.0 K(f)U and 23.1 +/- 8.4 mmHg, respectively; P < 0.001) in the group with a bad calibration signal. We suggest that the filtrass sensor, which performs an automatic, standardized calibration procedure and shows a linear signal response to stretch, gives highly reproducible and reliable results and thus is more suitable for routine application.

Changes in microvascular fluid filtration capacity during 120 days of 6 degrees head-down tilt.

We used venous congestion strain gauge plethysmography (VCP) to measure the changes in fluid filtration capacity (K(f)), isovolumetric venous pressure (Pv(i)), and blood flow in six volunteers before, on the 118th day (D118) of head-down tilt (HDT), and 2 days after remobilization (Post). We hypothesized that 120 days of HDT cause significant micro- and macrovascular changes. We observed a significant increase in K(f) from 3.6 +/- 0.4 x 10(-3) to 5.7 +/- 0.9 x 10(-3) ml. min(-1). 100 ml(-1). mmHg(-1) (+51.4%; P < 0.003), which returned to pretilt values (4.0 + 0.4 x 10(-3) ml. min(-1). 100 ml(-1). mmHg(-1)) after remobilization. Similarly, Pv(i) increased from 13.4 +/- 2.1 mmHg to 28.9 +/- 2.8 mmHg (+105.8%; P < 0.001) at D118 and was not significantly different at Post (12.4 +/- 2.6 mmHg). Blood flow decreased significantly from 2.3 +/- 0.3 to 1.3 +/- 0.2 ml. min(-1). 100 ml tissue(-1) at D118 and was found elevated to 3.4 +/- 0.7 ml. min(-1). 100 ml tissue(-1) at Post. We believe that the increased K(f) is caused by a higher microvascular water permeability. Because this may result in edema formation, it could contribute to the alterations in fluid homeostasis after exposure to microgravity.

Effects of confinement (110 and 240 days) on neuroendocrine stress response and changes of immune cells in men.

The aim of the study was to evaluate the effects of long-term confinement on stress-permissive neuroendocrine and immune responses in humans. Two groups of four male subjects were confined 240 days (group 240) or 110 days (group 110) in two space modules of 100 or 200 m3, respectively. During confinement, none of the volunteers developed psychic stress as could be examined and verified by a current stress test. However, in group 240 but not in group 110, the diurnal rhythm of cortisol secretion was slightly depressed and the urine excretion of norepinephrine significantly increased. The innate part of the immune system became activated as seen by a rise in the number of circulating granulocytes and the enhanced expression of beta2-integrins. In contrast, the ratio of T-helper to T-suppressor cells decreased. All these effects, observed during confinement, were even more pronounced in both groups when values of endocrinological and immunological parameters were compared between before and 1 wk after the end of the confinement period. Hence, return to normal life exerts pronounced effects to a much higher degree, irrespective of how long or under which conditions individuals were confined. Because the delayed-type hypersensitivity skin reaction against recall antigens remained unaffected, it is to be presumed that confinement appears to induce distinct sympathoadrenergic activation and immunological changes but no clinically relevant immunosuppression.

The expression of GAP-43 and synaptophysin in the developing rat retina.

We have undertaken a detailed study of the expression of GAP-43 and synaptophysin immunoreactivity in the developing postnatal rat retina. We found that these two 'presynaptic' proteins have quite different expression patterns. GAP-43 was first expressed in the optic nerve and the optic fiber layer of the retina, where it disappeared between the 8th and 16th postnatal day. From the 5th postnatal day on, GAP-43 also appeared in the inner plexiform layer, where it was present in three distinct bands. This expression changed little in postnatal development and persisted in the adult retina. GAP-43 was not detected in the outer plexiform layer of the retina. Synaptophysin was absent from the optic nerve and optic fibers at all postnatal stages. It was first expressed in the developing outer plexiform and, with reduced intensity, in the outer nuclear layer between postnatal days 2 and 5. In the inner plexiform layer, synaptophysin could be first detected between postnatal days 8 and 12. The intensity of staining increased during postnatal development in both plexiform layers. The developmental sequence of synaptophysin expression can be correlated with the maturation of presynaptic terminals of photoreceptors and bipolar cells. The rather complex pattern of GAP-43 expression is not easily compatible with a single model of GAP-43 function, and suggests diverse functions of this molecule in the retina.

The growth-associated protein GAP-43 is specifically expressed in tyrosine hydroxylase-positive cells of the rat retina.

In the adult retina, the growth-associated protein GAP-43 is exclusively present in three distinct sublaminae of the inner plexiform layer. During postnatal development, it is transiently expressed in the optic nerve fibers. No conclusions about the GAP-43 expressing cells can be derived from immunohistochemical stainings because GAP-43 protein is rapidly transported into the distal neuronal processes. We have combined immunohistochemistry to study the protein expression of GAP-43 and non-radioactive in situ hybridization to study the cellular expression of GAP-43 in the rat retina. We have found that in the mature retina GAP-43 mRNA is present only in retinal ganglion cells and in a small subset of cells of the inner nuclear layer. During postnatal development, no cells besides retinal ganglion cells and a subpopulation of cells in the inner nuclear layer express GAP-43 mRNA. Double staining experiments with tyrosine hydroxylase (TH) immunohistochemistry and GAP-43 in situ hybridization showed that GAP-43 expressing cells in the inner nuclear layer are immunoreactive for TH. They are most probably dopaminergic amacrine cells. Our results show that GAP-43 expression in the retina is restricted to very few cell types. They suggest that TH-positive cells (probably dopaminergic amacrine cells) retain a higher degree of structural plasticity in the adult retina.

Accelerated ultraviolet aging of intraocular lens optic materials: a 50 year simulation.

PURPOSE: To introduce an updated accelerated photoaging model for application to intraocular lens (IOL) materials and to apply this model to determine the photostability of AMO PhacoFlex model SI-18NGB and PhacoFlex II model SI-20NGB silicone IOL materials over a simulated 50 years of exposure. SETTING: Research laboratory, AMO Surgical Products, Irvine, California, USA. METHODS: Previous photoaging models and aging parameters, including intraocular exposure intensity, daily exposure duration, and acceleration exponent were critically reviewed and analyzed, and an updated model was introduced. The test specimens were continuously irradiated with ultraviolet (UV) light in a Suntest UV chamber at an intensity of 8 mw/cm2 for 86 days to simulate 50 years of in vivo exposure. The silicone lenses were evaluated for focal length, resolution, and surface integrity, while regular slabs were tested for tensile strength, elongation, hardness, contact angle, and percentage light transmission. The UV-absorption capacity was monitored using ultrathin slabs (0.127 mm). Six replicate samples were used for each determination, and a two-sided t-test with significance set at P < .05 was used to evaluate the difference before and after aging. RESULTS: No significant difference in optical, physical, and surface properties of the lenses and lens materials was found. No change in UV-absorption capacity was observed after a simulated 50 years of accelerated photoaging. CONCLUSION: The AMO PhacoFlex SI-18NGB and PhacoFlex II SI-30NGB silicone lens materials resisted UV light degradation over 50 years of simulated exposure.

Accelerated hydrolytic and ultraviolet aging studies on SI-18NB and SI-20NB silicone lenses.

This report describes the results of in vitro accelerated hydrolytic and ultraviolet aging studies performed on SI-18NB and SI-20NB silicone intraocular lenses. The hydrolytic aging study simulated the effects of 20 years in vivo. The ultraviolet aging study simulated the effects of 17 years in vivo. No significant changes in the focal length and resolution of the lenses were observed. Examination of the lens surfaces using scanning electron microscopy revealed no changes in surface morphology.

Moisture droplet formation on the posterior surface of intraocular lenses during fluid/air exchange.

We investigated the conditions under which moisture droplets would form on intraocular lens (IOL) posterior surfaces during fluid/air exchange procedures in rabbits implanted with silicone or poly(methyl methacrylate) (PMMA) IOLs. Moisture droplets did not form when the posterior capsule was intact, regardless of IOL material or infusion fluid temperature. If a capsular tear was present, droplets formed with both IOL materials when balanced salt solution (BSS) at ambient temperature was used as the infusion fluid. This effect was significantly more pronounced with silicone IOLs, resulting in an immediate loss of visualization of the fundus. In these cases, visualization was quickly restored by applying a viscoelastic to the posterior IOL surface.

Evaluation of the chemical, optical, and mechanical properties of elastomeric intraocular lens materials and their clinical significance.

The current trend toward small incision cataract surgery has resulted in the use of elastomers as intraocular lens materials. Little has been published on appropriate methods of evaluating biomaterials intended for implantation in the eye. We present a methodology for such a study and report the results for two elastomeric silicone intraocular lens materials. The chemical, optical, and mechanical properties of the two materials were evaluated, as was their stability to hydrolytic and ultraviolet degradation. Qualitative correlations between these properties and clinical requirements are discussed. Both silicone materials possessed the necessary properties for use as small incision intraocular lenses.

Magnetic resonance (MR) imaging of prostatic tumours, a comparison with X-ray CT and transrectal sonography (TRS).

A total of 7 healthy volunteers and 31 patients have been examined clinically, by MRI, TRS, and biopsy. In those patients with established carcinoma, a CT examination was also performed. For the MRI study, a superconducting MR 2000 imager (Picker International) operated at 0.15 T was used with multiplanar SE and IR sequences. SE sequences with long echo times detected prostatitis, adenoma and carcinoma of the prostate with a high degree of sensitivity. However, at present, differentiation between adenoma, prostatitis and carcinoma is not possible with sufficient accuracy. In these studies we were unable to establish a correlation between the signal pattern and staging and/or grading of the carcinoma. Reliable diagnosis of a prostate carcinoma still requires a biopsy. Because of the high soft tissue contrast and the possibility of selecting any orientation for the plane under investigation, however, MRI represents an improvement in the preoperative diagnosis of local spread.

[Ulno-volar bayonet hand: its differential diagnosis from Madelung's deformity (author's transl)]. / Die ulnovolare Bajonetthand in der Differentialdiagnose der Madelungschen Unterarmdeformität.

The ulno-volar bayonet hand related to the mostly hereditary multiple exostoses is compared to Madelung's forearm deformity under clinical and roentgenological view in differential diagnosis. The ulno-volar bayonet hand is considerably more seldom, basing upon dysplasia of the lower part of the ulna, less inconvenient in function, and hardly tending to the development of early arthrosis.

[The radiological image of pleural lipomas with special reference to computed tomography]. / Das radiologische Erscheinungsbild der pleuralen Lipome unter besonderer Berücksichtigung der Computertomographie.

Diagnostic assessment of focal pleural mass requires CT examination, particularly in follow-up of anamnestic tumour conditions. Since 1976 well-delineated pleural masses that were suspicious for malignancy on chest films, were identified in 11 patients as lipomas, using CT. They showed semicircular, oval or polygonal shape, but no really "spheric" aspect on biplane chest films. Main diameters of these masses were 2.5 to 6 cm and only once 11 cm. Density values mostly ranged from -110 to -70 HE (min. -133, max. -22 HE) in nonenhanced CT studies. Findings were localised adjacent to the parietal pleura seven times (in one patient two separate findings) and to the diaphragmatic pleura five times. In 7751 CT examinations of the chest, the incidence of pleural lipomas was 0.14%, their prevalence concerning solid pleural lesions being 5.3%. Among all intrathoracic lipomas those in mediastinal and paracardial location respectively were definitely more often (30 patients).