[Modified radiation administration in Er:YAG laser ab externo sclerostomy]

BACKGROUND

Ab externo sclerostomy enables the restrained aqueous humour drain via a microgram wide corneoscleral canal into the subconjunctival space being an alternative surgical method in glaucoma therapy. The tissue ablative infrared laser radiation (2.94 microgram) was applied until now via a quartz fiber manually pushed forward in permanent tissue contact. Our aim was the development of a new applicator tip without manual feed in order to achieve a reduction in times for construction and maintenance of the former tip as well as in the risk of an infection and mechanical damage of intraocular structures.

MATERIAL AND METHOD

In pig eye experiments, the laser parameters were varied in histological and scanning electron microscopic evaluation (pulse energy: 10-60 mJ, repetition rate: 5-17.5 Hz, combinations of constant power: 200 mW). Their influence on the canal shape and the morphology of the internal ostium has been proven in special tests.

RESULTS

The new development of the applicator tip (core diameter: 550 microgram) enables a conical profile of the beam (diameter 500-150 microgram) within a distance of 2-3 mm, now without pushing the fiber forward ("fixed fiber"). Smooth canal surfaces, a small homogeneous necrosis zone (25 microgram) and only few tissue ruptures have been seen histologically and on SEM. The correlations of ablation rates/-speed as well as canal characteristics are more significant to energy densities than to repetition rates. First clinical application was technically successful.

CONCLUSIONS

The new applicator tip optimizes the method of Er: YAG-laser ab externo sclerostomy from the technical and surgical point of view.

Energy transfer spectroscopy for measuring mitochondrial metabolism in living cells

Microscopic energy transfer spectroscopy was established using mixed solutions of reduced nicotinamide adenine dinucleotide (NADH) and the mitochondrial marker rhodamine 123 (R123). This method was applied to probe mitochondrial malfunction of cultivated endothelial cells from calf aorta incubated with various inhibitors of specific enzyme complexes of the respiratory chain. Autofluorescence of the coenzyme NADH as well as energy transfer efficacy from excited NADH molecules (energy donor) to R123 (energy acceptor) were measured by time-gated fluorescence spectroscopy. Because intermolecular distances in the nanometer range are required for radiationless energy transfer, this method is suitable to probe selectively mitochondrial NADH. Autofluorescence of endothelial cells usually exhibited a weak increase after specific inhibition of enzyme complexes of the respiratory chain. In contrast, pronounced and statistically significant changes of energy transfer efficacy were observed after inhibition of the same enzyme complexes. Detection of NADH and R123 in different nanosecond time gates following the exciting laser pulses enhances the selectivity and improves quantification of fluorescence measurements. Therefore, time-gated energy transfer spectroscopy is suggested to be an appropriate tool for probing mitochondrial malfunction.

High-level expression and purification of the major birch pollen allergen, Bet v 1

Bet v 1, the single major allergen from birch pollen, shares IgE epitopes with all major tree pollen allergens from closely related species such as alder, hazel, hornbeam, beech, and European chestnut. Because of high sequence homologies among these allergens and the well-studied cross-reactivities on B cell epitopes, Bet v 1 is a representative model protein which can be used for in vitro studies. The cDNA coding for Bet v 1, the single major allergen from birch pollen, was cloned into the T7-based Escherichia coli expression system pMW 175/BL21(DE3) and synthesized as a nonfusion protein. In contrast to other E. coli systems (e.g., pKK233-2/JM105), this system produces high levels of readily extractable proteins corresponding to 5-10% of E. coli total protein, the percentage varying with culture conditions. The overall yield was 8-10 mg of purified recombinant protein per liter of culture medium. The recombinant allergen was purified by several steps, including ion-exchange and hydrophobic interaction chromatography. The purified recombinant allergen showed identical immunological properties with the respective natural counterpart. The use of recombinant allergens of high purity is expected to result in more accurate diagnostic procedures, but possibly also in a superior immunotherapy of Type I allergic diseases when compared with methods using crude allergen extracts containing various amounts of allergen concentrations.

Dynamic fluorescence changes during photodynamic therapy in vivo and in vitro of hydrophilic A1(III) phthalocyanine tetrasulphonate and lipophilic Zn(II) phthalocyanine administered in liposomes

The fluorescence emission of hydrophilic tetrasulphonated aluminium phthalocyanine (AlPcS4) and hydrophobic zinc phthalocyanine (ZnPc), bound to the membrane of liposomes, was investigated in vivo in an appropriate tumour model of the rat bladder and in RR 1022 epithelial cells of the rat. The sensitizers were administered systemically to the rats and photodynamic therapy (PDT) was performed 24 h later. During PDT treatment, the fluorescence was measured every 30 s. The fluorescence was excited with 633 nm light from an HeNe laser and the fluorescence spectra were detected with an optical multichannel analyser system. PDT was performed for both sensitizers using 672 nm light from an Ar+ dye laser. The fluorescence changes during PDT were significantly different for the two phthalocyanines. For AlPcS4, an initial fluorescence intensity increase, followed by subsequent photobleaching, was observed. In contrast, ZnPc fluorescence showed an exponential decrease and no increase at the start of treatment. Tumour necrosis 24 h after PDT was significant only for ZnPc. RR 1022 cells incubated for 24 h with AlPcS4 revealed a granular fluorescence pattern, whereas ZnPc was localized diffusely in the cytoplasm of the cells. In agreement with the in vivo measurements, subcellular relocalization and a fluorescence intensity increase were detected exclusively in the case of AlPcS4. Morphological changes at this time were significant only for ZnPc. The subcellular localization and fluorescence kinetics were obtained using a confocal laser scanning microscope.

Regeneration processes in rabbit endometrium: a photodynamic therapy model

The origin and process of regeneration in rabbit endometrium was evaluated following photodynamic epithelial destruction using topically applied aminolevulinic acid (ALA). Selective destruction of endometrial epithelium was performed using photodynamic therapy (PDT). ALA was diluted to 200 mg/ml dextran 70 shortly prior to administration. A volume of 1.2 ml was injected into the left uterus. Intrauterine illumination (wavelength 630 nm, light dose 40-80 J/cm2) was performed 3 h after drug administration. Tissue morphology was evaluated by light and scanning electron microscopy 1, 3, 7 and 28 days post-treatment (three animals at each time-point). Regeneration of the endometrium following epithelial ablation by PDT was fully activated after 24 h and was completed after 72 h. Endometrial surface generation occurred by proliferation, originating primarily in deeper regions of the glands. Findings from our morphological follow-up study support the origin of endometrial regeneration being mainly from undifferentiated stem cells and residual glandular epithelium.

[Concomitant injuries after upper ankle joint dislocations]

Functional treatment with the Air Stirrup Ankle Brace recommended by C. N. Stover in 1979 can reduce pathological inversion of the ankle joint. In our retrospective study of 109 patients treated by this kind of ankle brace we found 96 patients (88%) with excellent results. Only 13 patients (12%) reported moderate to good results. To detect and characterize their painful conditions of ankles we did a clinical, radiological and MRI-Investigation. In only 2 cases we found a moderate instability after clinical investigation, anterior stress roentgenogram and talar tilt. By using the MRI-investigation 1.0 Tesla with a 512 x 360 Matrix we could find 10 cases with osteochondral lesions of the ankle. In 7 cases there was separated ossicle in the fibulotalar joint, in 1 case we detected a fracture of the processus anterior tali, in another case we could see a posttraumatic lesion of the talus and calcaneus with bone bruise and at least one osteochondral fracture of the distal tibia. The capability of the MRI to detect particularly osteo-chondral lesions of the talus and the tibiofibular joint was shown in 10 of 13 cases. Therefore we recommend to do an MRI-investigation on all patients after ankle sprain if there are painful conditions within the ankle after conservative treatment.

Immunoglobulin E response to human proteins in atopic patients

The demonstration that human IgE recognizes both exogenous allergens and structurally related human proteins has led to the hypothesis that IgE autoreactivity may be a pathogenic factor in atopic diseases. To determine the frequency of occurrence as well as the disease specificity of this phenomenon, we tested sera from patients with atopic diseases and, for control purposes, from persons with immunologically mediated disorders for serum IgE reactivity with nitrocellulose-blotted human proteins. We found that 12 of 20 sera from atopic patients with pronounced skin lesions contained Western blot-detectable IgE antibodies. Patients suffering predominantly from allergic rhinoconjunctivitis as well as control individuals failed to display serum IgE autoreactivity, but occasionally exhibited elevated serum IgE levels. The molecular weights of the IgE-defined autoantigens ranged predominantly from 10 to 100 kDa. Whereas some of these were expressed in only certain cell types, others were detected in histogenetically different cells. Our results suggest that IgE autoimmunity occurs frequently in atopic dermatitis patients and may be of pathogenic relevance for the chronicity of skin manifestations typical of this disease.

Determination of the scattering coefficient and the anisotropy factor from laser Doppler spectra of liquids including blood

Laser Doppler measurements were performed on scattering liquids flowing through a highly scattering static medium to determine the scattering coefficient and the anisotropy factor of the liquids. Monte Carlo simulations of light propagation in the static and moving media were used to calculate the Doppler spectra for suspensions of polystyrene spheres in water, and these spectra were in excellent agreement with experimental results. A faster Monte Carlo code was developed so that nonlinear regressions to the measured laser Doppler spectra could be used to determine the anisotropy factor of other liquids. This approach was used to deduce the scattering properties of Intralipid and blood at λ = 820 nm. It was found that the anisotropy factor of blood is well described by Mie theory in contradiction to results reported in the literature that were obtained by goniometric measurement of the phase function.

Spatially resolved absolute diffuse reflectance measurements for noninvasive determination of the optical scattering and absorption coefficients of biological tissue

The absorption and transport scattering coefficients of biological tissues determine the radial dependence of the diffuse reflectance that is due to a point source. A system is described for making remote measurements of spatially resolved absolute diffuse reflectance and hence noninvasive, noncontact estimates of the tissue optical properties. The system incorporated a laser source and a CCD camera. Deflection of the incident beam into the camera allowed characterization of the source for absolute reflectance measurements. It is shown that an often used solution of the diffusion equation cannot be applied for these measurements. Instead, a neural network, trained on the results of Monte Carlo simulations, was used to estimate the absorption and scattering coefficients from the reflectance data. Tests on tissue-simulating phantoms with transport scattering coefficients between 0.5 and 2.0 mm(-1) and absorption coefficients between 0.002 and 0.1 mm(-1) showed the rms errors of this technique to be 2.6% for the transport scattering coefficient and 14% for the absorption coefficients. The optical properties of bovine muscle, adipose, and liver tissue, as well as chicken muscle (breast), were also measured ex vivo at 633 and 751 nm. For muscle tissue it was found that the Monte Carlo simulation did not agree with experimental measurements of reflectance at distances less than 2 mm from the incident beam.

[Ab externo sclerostomy with the Er:YAG laser: report of outcome after 2 years]

OBJECT

Results over a period of 24 months of performing the Er:YAG laser ab externo sclerostomy.

MATERIAL AND METHODS

The procedure was performed 81 times (chronic glaucoma with open angle (n = 55) and narrow angle (n = 15), 6 secondary glaucoma, 4 pigment glaucoma, 1 normal pressure glaucoma) in 74 eyes of 64 patients at the age of 70 +/- 10 years without any peribulbar anesthesia. The pulse energy was 11 mJ with a repetition rate of 7 Hz. Antimetabolites were not applicated. Success was defined as an IOP of less than 22 mm Hg or a decrease of at least 30%, with or without anti-glaucoma medication.

RESULTS

The mean IOP of all cases decreased from preoperatively 28 +/- 8.1 mm Hg (Success group: 26.7 +/- 7.3 mm Hg) to 15 +/- 8.4 mm Hg (Success group: 14.6 +/- 7.8 mm Hg) on the first postoperative day. The success rate was about 50% within the period of two weeks to six months and decreased to about 15% in the 24th month. Complications were iris incarceration/synechia (n = 33), hypotony (n = 36) with consequent choroidal detachment (n = 8), hyphema (n = 19) and more pronounced inflammation symptoms (n = 10). In most cases, the early postoperative outflow failure is caused by iris incarceration into the internal ostium. The scarring tendency of the episcleral tissue leads to closure of the external ostium after months. Resurgery was necessary in 26 cases.

CONCLUSIONS

Further efforts should be directed to maintain the intact corneoscleral morphology of the canal, created by an optimized method of the surgical technique. The application of antimetabolites in correct dosage or the implantation of modified silicon draining systems would be helpful.

Why do veins appear blue? A new look at an old question

We investigate why vessels that contain blood, which has a red or a dark red color, may look bluish in human tissue. A CCD camera was used to make images of diffusely reflected light at different wavelengths. Measurements of reflectance that are due to model blood vessels in scattering media and of human skin containing a prominent vein are presented. Monte Carlo simulations were used to calculate the spatially resolved diffuse reflectance for both situations. We show that the color of blood vessels is determined by the following factors: (i) the scattering and absorption characteristics of skin at different wavelengths, (ii) the oxygenation state of blood, which affects its absorption properties, (iii) the diameter and the depth of the vessels, and (iv) the visual perception process.

Are coping strategies related to disease outcome in early breast cancer?

A consecutive series of 107 women with early breast cancer were investigated for coping strategies and disease outcome 5 to 6 years after primary surgical treatment (mastectomy or lumpectomy). Coping was assessed several times during a 3-year investigation period by the Zurich and Freiburg Questionnaires of Coping with Illness (ZQCI, FQCI). Data analysis revealed no significant correlations between coping strategies and the target variable "death from breast cancer". However, significant relations were found between postsurgical tumour size (p < or = 0.01), positive histological node status (p < or = 0.01) and death from breast cancer. The results of a discriminant analysis also indicated that somatic parameters are more important for the course of breast cancer disease than psychological aspects of coping. The role of psychosocial variables for the outcome of cancer disease remains unclear and further studies in this field are necessary.

Erbium:YAG laser photoablation of human cornea

PURPOSE

To determine whether the healing response of the human cornea after photoablation with a midinfrared solid-state laser was more pronounced than after excimer laser keratectomies because of the increased thermal damage in adjacent tissue.

METHODS

We treated five blind human eyes with an erbium:YAG (Er:YAG) laser prototype and followed up the patients for nine months.

RESULTS

Regarding epithelial healing and corneal clarity, the patients had a healing response very similar to that of excimer laser. Further clinical and experimental studies are necessary to estimate healing and regression.

'Et in arcadia ego...?' Some notes on methodological issues in the use of psychoanalytic documents and archives

The author uses archival material, mainly the letters exchanged between Jones and Strachey in the fifties, when Jones was writing his biography of Freud and Strachey was working on the Standard Edition. He shows the complexity of the interaction between these two men; the more or less conscious ambivalences, motivations and resentments against the so-called Freudian establishment of that time. This per se can help us to understand how a 'certain image' of Freud was created in Great Britain during those years and the reasons for its authoritative persistence. Yet the paper touches on more general issues such as those of the fascination with psychoanalytic archives and the more or less accepted and admitted unconscious motivations of the interpreters of these documents too, not excluding myself. The conclusion reached is that even psychoanalytical documents do not rest in a peaceful Arcadia and that archives cannot be considered as the Arcadia of documents--at least not in the ways that Arcadia has always been considered and interpreted, misleadingly, even in two paintings by Poussin, which I refer to in my paper. These in reality remind us that in Arcadia there is death too. Even the memory that the documents should help us to conserve is ineluctably bound to loss, dissemination, mutilation and uncertainty, and therefore must also face the presence of death also.

An investigation of differences between three age groups in verbal and spatial task performance using the dual-task paradigm

A dual-task paradigm with concurrent verbal and spatial tasks was used to investigate differences across three age groups for lateralized effects, magnitude of tapping interference, and cognitive task output. In addition, rescaled scores comparing verbal with spatial measures within and across age groups were analyzed to examine asymmetric age differences for right versus left hemisphere abilities. Results of the present dual task finger tapping investigation of three age groups showed all groups left lateralized for verbal tasks and right lateralized for spatial tasks. However, the magnitude of interference in tapping was significantly greater in paced nonideational shadowing tasks and during paced purposeful spatial tasks. Outcomes of exploratory analyses suggest a complex interplay between aptitude and the corresponding lateralized effects and cognitive effort to perform the task.