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K Fischer

Publications and source records attributed to K Fischer.

At least 37 records · Page 2Linked to original sources
PubMed2000

Control of carbon partitioning and photosynthesis by the triose phosphate/phosphate translocator in transgenic tobacco plants (Nicotiana tabacum L.). I. Comparative physiological analysis of tobacco plants with antisense repression and overexpression of the triose phosphate/phosphate translocator.

The physiological properties of transgenic tobacco plants (Nicotiana tabacum L.) with decreased or increased transport capacities of the chloroplast triose phosphate/phosphate translocator (TPT) were compared in order to investigate the extent to which the TPT controls metabolic fluxes in wild-type tobacco. For this purpose, tobacco lines with an antisense repression of the endogenous TPT (alphaTPT) and tobacco lines overexpressing the TPT gene isolated from the C4 plant Flaveria trinervia (FtTPT) were used. The F. trinervia TPT expressed in yeast cells exhibited transport characteristics identical to the TPT from C3 plants. Neither antisense TPT plants nor FtTPT overexpressors showed a phenotype when grown in a greenhouse in air. Contents of starch and soluble sugars in upper source leaves were similar in TPT underexpressors and FtTPT overexpressors compared to the wild type at the end of the photoperiod. The FtTPT overexpressors incorporated more 14CO2 in sucrose than the wild type, indicating that the TPT limits sucrose biosynthesis in the wild type. There were only small effects on labelling of amino acids and organic acids. The mobilisation of starch was enhanced in alphaTPT lines but decreased in FtTPT overexpressors compared to the wild type. Enzymes involved in starch mobilisation or utilisation, such as alpha-amylase or hexokinase were increased in alphaTPT plants and, in the case of amylases, decreased in FtTPT overexpressors. Moreover, alpha-amylase activity exhibited a pronounced diurnal variation in alphaTPT lines with a maximum activity after 8 h in the light. These changes in starch hydrolytic activities were confirmed by activity staining of native gels. Activities of glucan phosphorylases were unaffected by either a decrease or an increase in TPT activity. There were also effects of TPT activities on steady-state levels of phosphorylated intermediates as well as total amino acids and malate. In air, there was no or little effect of altered TPT transport activity on either rates of photosynthetic electron transport and/or CO2 assimilation. However, in elevated CO2 (1500 microl x l(-1)) and low O2 (2%) the rate of CO2 assimilation was decreased in the alphaTPT lines and was slightly higher in FtTPT lines. This shows that the TPT limits maximum rates of photosynthesis in the wild type.

Carbon Dioxide↗
PubMed2000

Modified ultrafiltration lowers adhesion molecule and cytokine levels after cardiopulmonary bypass without clinical relevance in adults.

OBJECTIVE: Cardiac surgery with cardiopulmonary bypass (CPB) results in expression of cytokines and adhesion molecules (AM) with subsequent inflammatory response. The purpose of the study was to evaluate the clinical impact of modified ultrafiltration (MUF) and its efficacy in reducing cytokines and AM following coronary artery bypass grafting (CABG) in adults. METHODS: A prospective randomized study of 97 patients undergoing elective CABG was designed. Fifty patients were operated on using normothermic and 47 patients using hypothermic CPB. The normothermic group was subdivided into a group with modified ultrafiltration (n = 30) and a group without MUF (n = 20). In the hypothermic group 30 patients received MUF compared to 17 patients serving as controls. MUF was instituted after CPB for 15 min through the arterial and venous bypass circuit lines. Cytokines (IL-6, IL-8, TNF-alpha, IL-2R) and adhesion molecules (sE-selectin, sICAM-1) were measured preoperatively, pre-MUF, in the ultrafiltrate, 24 h, 48 h and 6 days after surgery by chemiluminescent enzyme immunometric assay or enzyme-linked immunosorbent assay (ELISA). Clinical parameters were collected prospectively until discharge. RESULTS: In all patients AM and cytokines were significantly elevated after normothermic and hypothemic CPB. AM and cytokines were significantly higher in hypothermia compared to normothermia. In hypothermic CPB sE-selectin was decreased after 24 h by 37% (P < 0.0063) and by 40% (P < 0.0027) after 48 h postoperatively. ICAM-1 was reduced by 43% (P < 0.0001) after 24 h and by 60% (P < 0.0001) after 6 days. Similar results were seen in cytokines with reduction up to 60% after 24 h. Changes after 48 h were noticeable but not significant. Reduction of AM and cytokines after normothermic CPB was minimal. Neither in normothermia, nor in hypothermia has sIL-2R been effectively removed from the circulation. There were no significant differences in the clinical variables between the patients with or without MUF. CONCLUSION: AM and cytokines are significantly elevated after hypothermic CPB compared to normothermic CPB. MUF led to a significant reduction in cytokine and AM levels after hypothermic CPB, except for IL-2R. MUF showed minimal effect in normothermia. We conclude that MUF is an efficient way to remove cytokines and AM. However, we were unable to demonstrate any significant impact of MUF in outcome of adults after elective CABG.

Adult↗
PubMed2000

Plastidic metabolite transporters and their physiological functions in the inducible crassulacean acid metabolism plant Mesembryanthemum crystallinum.

The inducible crassulacean acid metabolism (CAM) plant Mesembryanthemum crystallinum accumulates malic acid during the night and converts it to starch during the day via a pathway that, because it is located in different subcellular compartments, depends on specific metabolite transport across membranes. The chloroplast glucose transporter (pGlcT) and three members of the phosphate translocator (PT) family were isolated. After induction of CAM, transcript amounts of the phosphoenolpyruvate (PEP) phosphate translocator (PPT) and the glucose-6-phosphate (Glc6P) phosphate translocator (GPT) genes were increased drastically, while triose phosphate (TP) phosphate translocator (TPT) and the pGlcT transcripts remained unchanged. PPT- and GPT-specific transcripts and transporter activities exhibited a pronounced diurnal variation, displaying the highest amplitude in the light. pGlcT transcripts were elevated towards the end of the light period and at the beginning of the dark period. These findings, combined with diurnal variations of enzyme activities and metabolite contents, helped to elucidate the roles of the PPT, GPT, TPT and pGlcT in CAM. The main function of the PPT is the daytime export from the stroma of PEP generated by pyruvate orthophosphate:dikinase (PPDK). The increased transport activity of GPT in the light suggests a higher requirement for Glc6P import for starch synthesis rather than starch mobilization. Most likely, Glc6P rather than 3-phosphoglycerate or triose phosphates is the main substrate for daytime starch biosynthesis in M. crystallinum plants in which CAM has been induced (CAM-induced), similar to non-green plastids. In the dark, starch is mobilized both phosphorylytically and amylolytically and the products are exported by the GPT, TPT and pGlcT. The transport activities of all three phosphate translocators and the transcript amounts of the pGlcT adapt to changing transport requirements in order to maintain high metabolic fluxes during the diurnal CAM cycle.

Biological Transport, Active↗
PubMed2000

Chromatographic properties of the ion-exclusion column IonPac ICE-AS6 and its application in environmental analysis, Part II: application in environmental analysis

Biological processes, geochemical reactions, anthropogenic emissions, and transformation reactions of xenobiotics are responsible for the widespread occurrence of aliphatic carboxylic acids in the environment. To study the performance of the ion-exclusion chromatography column IonPac ICE-AS6 in the analysis of environmental and environmental-technical samples, organic acids are investigated in composting seepage, silage effluents, aqueous extracts of sewage sludge, molasses hydrolysate, and alkaline cellulose hydrolysates. With respect to the diverse sample matrix and composition, different chromatographic conditions are applied. It is possible to determine various volatile fatty acids, dicarboxylic acids, (poly)hydroxy acids, and keto acids as main and trace components in samples with very high and low dissolved organic carbon content. Low baseline noise allows the determination of malic and succinic acid in the concentration range of approximately 1 microM/L in the presence of higher concentrations of fully ionized compounds. The applicability of the column in environmental analysis may be limited by the poor retardation of strong organic acids, insufficient separation of some relevant substance combinations (i.e., citric and isocitric acid), and very strong hydrophobic interactions with straight-chain monocarboxylic acids containing four or more carbon atoms.

Journal Article↗
PubMed2000

Open bite: stability after bimaxillary surgery--2-year treatment outcomes in 58 patients.

Stability after bimaxillary surgery to correct open bite malocclusion and mandibular retrognathism was evaluated on lateral cephalograms before surgery, 8 weeks post-operatively, and after 2 years. The 58 consecutive patients were treated to a normal occlusion and good facial aesthetics. Treatment included the orthodontic alignment of teeth by maxillary and mandibular fixed appliances, Le Fort I osteotomy, and bilateral sagittal split ramus osteotomy. Twenty-six patients also had a genioplasty. Intra-osseous wires or bicortical screws were used for fixation. Twenty-three patients had maxillo-mandibular fixation (MMF) for 8 weeks or more, six for 4-7 weeks, 14 for 1-3 weeks, and 15 had no fixation. At follow-up 2 years later, the maxilla remained unchanged and the mandible had rotated on average 1.4 degrees posteriorly. Seventeen patients had an open bite. Among them, eight patients had undergone segmental osteotomies. The relapse was mainly due to incisor proclination. The most stabile overbite was found in the group with no MMF after surgery.

Adolescent↗
PubMed2000

Cyproterone acetate reduced antler growth in surgically castrated fallow deer.

We studied the role of androgens in antler growth. In particular, we investigated whether the onset of antler regrowth is triggered by a short-term pulse of testosterone and if low levels of androgens are required for antler growth. The study was conducted on 12 surgically castrated fallow deer bucks (Dama dama) aged approximately 27 months. Six animals (CA group) were given the antiandrogen, cyproterone acetate (CA, 1000 mg/treatment); the others were given vehicle solution only (control). Before each CA treatment, blood was sampled and analysed for testosterone, androstenedione, IGF-1, cortisol, FSH, and LH. CA treatment and blood sampling were performed 2 days before castration, on the day of castration and afterwards at 2-day intervals until day 22. Subsequently, CA treatment and blood sampling continued at weekly intervals until day 270. All animals cast their antlers, followed by antler regrowth in all control bucks, but in only four of the six CA-treated castrates. Plasma testosterone concentrations were low in all animals (between 0.01 and 0.20 ng/ml), but were significantly (P<0001) greater in the controls. In both groups, a temporary increase in testosterone values was recorded around the time of antler regrowth, the peak being significantly (P<0.01) higher in the controls. Androstenedione showed a similar pattern as testosterone. Plasma IGF-1 concentrations increased sharply during the antler growth spurt and did not differ significantly between the two groups throughout the study period. Cortisol concentrations were greater in controls than in the CA group. However, no link with the antler cycle was apparent. FSH and LH concentrations were higher in the controls for most of the study. Antlers produced by the control bucks were significantly larger than those in the CA group (P<0.03). For antler length, testosterone, androstenedione and IGF-1, areas under the curve (AUC) were calculated over the period of antler growth. For the pooled deer (n=12) significant correlations existed between AUCs of antler length and testosterone, but not for antler length and IGF-1. Also, a trend for a positive correlation between AUCs of antler length and androstenedione was noted. It is concluded that a plasma androgen concentration at least above a minimal threshold level is a necessary prerequisite for normal antler regrowth in fallow deer, and that this androgen effect is not mediated via circulating IGF-1. The biological role of low levels of androgens may be to sensitize antler cells to the stimulating effect of IGF.

Androgen Antagonists↗
PubMed2000

[Antiphospholipid antibodies in high-risk pregnancy].

UNLABELLED: Recently the connection of antiphospholipid antibodies (aPLs) presence with pregnancy loss and complications in pregnancy has been observed APLs related obstetric complications include: miscarriages after 10 weeks, IUGR, intrauterine foetal death, preeclampsia and severe preeclampsia. Our objective was to determine the aPLs prevalence in patients with recurrent pregnancy loss and/or complicated pregnancy. We examined 154 pregnant women aged 19-42 (average of 29.1) with recurrent pregnancy loss, current pregnancy complicated by preeclampsia and severe preeclampsia and/or IUGR, thrombotic episodes, thrombocytopenia or autoimmune disease. In all the patients anticardiolipin antibodies (aCL) were determined at least twice using ELISA and their coagulation system was tested including lupus anticoagulant (LA) test. In justified cases immunological examinations detecting connective tissue systemic diseases were conducted. Increased aCL titre was detected in 54 (34.4%) women. Statistically significant risk of increased aCL titre was observed in patients with autoimmunological diseases (RR = 4.3). Increased, but Statistically insignificant, risk of high aCL titre was observed in patients with venous thrombosis (RR = 2.45) as well as in patients with thrombocytopenia (RR = 2.45). LA prevailed significantly more often in patients with venous thrombosis episodes (RR = 6.33) and with autoimmunological diseases (RR = 17.4). Preterm deliveries were significantly more frequent in pregnant women with increased aCL titre and/or LA. Moreover, in this group foetal death and preterm stillbirth more often occurred. The above mentioned risks increased when aCL and LA coexisted. No relation between increased aPLs and miscarriage frequency was observed. CONCLUSIONS: 1) Increased aPLs titre prevail in multiparas with bad obstetrical anamnesis and with pathological course in present pregnancy, 2) increased aPLs titre prevail in patients with autoimmunological diseases, 3) increased aPLs titre are connected with pregnancy pathology manifested by frequent preterm deliveries and intrauterine foetal deaths.

Adult↗
PubMed2000

Endogenous clotting factor activity and long-term outcome in patients with moderate haemophilia.

In order to address the question of the optimum target level for prophylactic treatment of severe haemophilia patients, the association between endogenous clotting factor activity and outcome was studied in a cohort of 46 patients with moderate haemophilia. Data on treatment and outcome were collected annually. Median follow-up was 8.0 years (range 1-26). Median joint bleed frequency was 1 per year and median radiological score according to Pettersson was 1 point (max. 78) at the age of 25 years. One percent increase in clotting factor level was associated with a 4 months later onset of joint bleeds (95% Confidence Interval (CI): 2-6 months) and a 16% lower Pettersson score (95% CI: 3-27%). No statistically significant effect of clotting factor activity on joint bleed frequency could be demonstrated. These findings confirm that patients with moderate haemophilia experience only mild arthropathy, and provide evidence for a protective effect of higher clotting factor levels on joint damage.

Adolescent↗
PubMed1999

Continuous in vitro propagation and differentiation of cultures of the intramolluscan stages of the human parasite Schistosoma mansoni.

The metazoan parasitic blood flukes, Schistosoma spp., infect over 200 million people worldwide and cause extensive human morbidity and mortality. Research strategies for development of anti-schistosomal agents are impeded by the organism's complex molluscan-mammalian life cycle, which limits experimental approaches and availability of material. We derived long-term continuously proliferative cultures of Schistosoma mansoni sporocysts capable of generating cercariae in vitro. Cultured organisms retained the ability to parasitize the host, and they exhibited developmental regulation of candidate stage-specific genes in the host-free culture system. Evidence for expression of a reverse transcriptase also was found in the cultured organisms, pointing to this activity as a possible mechanistic contributor to the dynamic relationship between the parasite and its hosts. Continuous in vitro propagation of the asexual sporocyst stage allows isolation of clonally derived parasite populations and provides a means to study schistosomal molecular genetics, metabolism, and evasion of host defenses.

Animals↗
PubMed1999

Substrate inhibition and affinities of the glyoxysomal beta-oxidation of sunflower cotyledons

During the glyoxysomal beta-oxidation of long-chain acyl-CoAs, short-chain intermediates accumulate transiently (Kleiter and Gerhardt 1998, Planta 206: 125-130). The studies reported here address the underlying factors. The studies concentrated upon the aspects of (i) chain length specificity and (ii) metabolic regulation of the glyoxysomal beta-oxidation of sunflower (Helianthus annuus L.) cotyledons. (i) Concentration-rate curves of the beta-oxidation of acyl-CoAs of various chain lengths showed that the beta-oxidation activity towards long-chain acyl-CoAs was higher than that towards short-chain acyl-CoAs at substrate concentrations <20 &mgr;M. At substrate concentrations >20 &mgr;M, long-chain acyl-CoAs were beta-oxidized more slowly than short-chain acyl-CoAs because the beta-oxidation of long-chain acyl-CoAs is subject to substrate inhibition which had already started at 5-10 &mgr;M substrate concentration and results from an inhibition of the multifunctional protein (MFP) of the beta-oxidation reaction sequence. However, low concentrations of free long-chain acyl-CoAs are rather likely to exist within the glyoxysomes due to the acyl-CoA-binding capacity of proteins. Consequently, the beta-oxidation rate towards a parent long-chain acyl-CoA will prevail over that towards the short-chain intermediates. (ii) Low concentrations (</=5 &mgr;M) of a long-chain acyl-CoA exerted an inhibitory effect on the beta-oxidation rate of butyryl-CoA. Reversibility of the inhibition was observed as well as metabolization of the inhibiting long-chain acyl-CoA. Regarding the activities of the individual beta-oxidation enzymes towards their C(4) substrates in the presence of a long-chain acyl-CoA, the MFP activity exhibited strong inhibition. This inhibition appears not to be due to the detergent-like physical properties of long-chain acyl-CoAs. The results of the studies, which are consistent with the observation that short-chain intermediates accumulate transiently during complete degradation of a long-chain acyl-CoA, suggest that the substrate concentration-dependent chain-length specificity of the beta-oxidation and a metabolic regulation at the level of MFP are factors determining this transient accumulation.

Journal Article↗
PubMed1999

Studies of the behaviour and fate of the polymer-additives octadecyl-3-(3.5-di-t-butyl-4-hydroxyphenyl)propionate and tri-(2.4-di-t-butylphenyl)phosphite in the environment.

In order to evaluate the environmental risk potential of the polymer-additives octadecyl-3-(3.5-di-t-butyl-4-hydroxyphenyl)propionate (additive 1) and tri-(2.4-di-t-butylphenyl)phosphite (additive 2) we have studied the degradation of the 14C-labelled single components and their release from a polypropylene matrix in abiotic and biotic test systems as well as their transport behaviour in soil. The biotic degradation in waste compost, activated sludge and in soil was studied. In order to conduct release tests, waste disposal material were used as well. The abiotic degradation was effectuated by photooxidation at a catalytic surface. The highest mineralisation rates were obtained by photooxidative degradation of the two test substances. The maximum content of bounded residues was found for additive 1 in soil and for additive 2 in waste compost. In the extracts of soil and compost, the principal metabolites could be identified in the case of additive 1 as 7.9-di-t-butyl-1-oxaspiro[4.5]deca-6.9-dien-2.8-dion and in activated sludge as the methyl ester of 3-(3.5-di-t-butyl-4-hydroxyphenyl) propionic acid. Additive 2 metabolised in all degradation tests nearly completely under formation of two products. The main component was identified as tri-(2.4-di-t-butylphenyl)phosphate. Both polymer-additives were eluated from the chosen soil types. The transport behaviour of additive 1 was independent from the soil type. In all test matrices additive 1 as well as additive 2 were released from polypropylene. Because the amounts of additive 1 and 2 absorbed onto soil particles were taken into account, the highest liberation rates were found in the soil test.

Antioxidants↗
PubMed1999

Laser angioplasty of restenosed coronary stents: results of a multicenter surveillance trial. The Laser Angioplasty of Restenosed Stents (LARS) Investigators.

OBJECTIVES: This study evaluated safety and efficacy of excimer laser angioplasty for treatment of restenosed or occluded coronary stents. BACKGROUND: Balloon angioplasty of in-stent restenosis is limited by a high recurrence rate. Debulking by laser angioplasty is a novel concept to treat in-stent restenosis. METHODS: A total of 440 patients with restenoses or occlusions in 527 stents were enrolled for treatment with concentric or eccentric laser catheters and adjunctive balloon angioplasty. RESULTS: Laser angioplasty success (< or =50% diameter stenosis after laser treatment or successful passage with a 2.0-mm or 1.7-mm eccentric laser catheter) was achieved in 92% of patients. Adjunctive balloon angioplasty was performed in 99%. Procedural success (laser angioplasty success followed by < or =30% stenosis with or without balloon angioplasty) was 91%. There was neither a significant difference in success with respect to lesion length, nor were there differences between small and large vessels or native vessels and vein grafts. Success was higher and residual stenosis lower using large or eccentric catheters. Serious adverse events included death (1.6%, not directly laser catheter related), Q-wave myocardial infarction (0.5%), non-Q-wave infarction (2.7%), cardiac tamponade (0.5%) and stent damage (0.5%). Perforations after laser treatment occurred in 0.9% of patients and after balloon angioplasty in 0.2%. Dissections were visible in 4.8% of patients after laser treatment and in 9.3% after balloon angioplasty. Reinterventions during hospitalization were necessary in 0.9% of patients; bypass surgery was performed in 0.2%. CONCLUSIONS: Excimer laser angioplasty with adjunctive balloon angioplasty is a safe and efficient technology to treat in-stent restenoses. These data justify a randomized comparison with balloon angioplasty.

Adult↗
PubMed1999

Increased doxorubicin uptake and toxicity in multicellular tumour spheroids treated with DC electrical fields.

Electrochemotherapy (ECT) is a new approach to the treatment of tumours. In the present study, multicellular prostate tumour spheroids were treated with non-lethal direct current (DC) electrical fields, and uptake and toxicity of doxorubicin were investigated. An electrical field with a field strength of 500 Vm(-1) applied for a duration of 90 s resulted in neither reversible nor irreversible membrane breakdown as revealed by fluid phase uptake studies of the membrane impermeant tracer Lucifer yellow. However, treated spheroids showed an increased uptake of doxorubicin and, consequently, an increased toxicity following electrical field exposure. The electrical field raised intracellular reactive oxygen species (ROS) as revealed using 2',7'-dichlorofluorescein diacetate (H2DCFDA) as an indicator. ROS induced membrane lipid peroxidation since the lipid peroxidation end products malondialdehyde (MDA) and 4-hydroxy-2-(E)-nonenal (4-HNE) were detected after electrical field treatment. Moreover, lipid peroxidation decreased the lipid diffusion coefficient D from 4.2 x 10(-10) cm2 s(-1) to 2.7 x 10(-10) cm2 s(-1) in the control and treated sample, respectively, as revealed by fluorescence recovery after photobleaching (FRAP) experiments. The field effects could be mimicked by incubating spheroids with 100 nM hydrogen peroxide and were inhibited by the radical scavengers dehydroascorbate (DHA) and alpha-tocopherol (vitamin E), indicating that the increased uptake of doxorubicin after electrical field treatment is owing to lipid peroxidation and decreased membrane lipid mobility. Treatment of tumours with low intensity electrical fields may be useful to improve the cytotoxic capacity of anthracyclines.

Antineoplastic Agents↗
PubMed1999

[Ultrasound biomicroscopy and therapy of malignant glaucoma].

BACKGROUND: Malignant glaucoma is a rarely diagnosed condition though it has been known since over one hundred years and understood to be based on an ciliary blockage since thirty years. Now it is possible to visualise pathomechanism of ciliary block by ultrasoundbiomicroscopy. PATIENTS AND METHODS: Between January 1994 and November 1998 thirteen patients with ciliary block glaucoma had been observed. Four underwent ultrasoundbiomicroscopy. RESULTS: Ciliary block glaucoma is caused by obliteration of the posterior chamber. Ultrasoundbiomicroscopy showed, that in phakic eyes the lens, in pseudophakic eyes the capsule together with the anterior vitreous membrane and in aphakic eyes the vitreous alone are the blocking agents. Hyperopia, a narrow iridocorneal angle and ciliary sulcus as well as plateau iris configuration and a history of miotics are the predisposing risks for ciliary block glaucoma, especially after additional surgery such as cataract extraction, iridotomy, iridectomy and trabeculectomy. Clinical features are always a raised intraocular tension accompanied with a flattening of the anterior chamber, which are to be differentiated from an angle closure glaucoma. This is easy, if iridectomy, irido-capsulovitreotomy or pseudophakia are present and difficult in the very rare spontaneous cases. Cycloplegics and YAG-laser iridectomy may break the ciliary block, but the most preferable therapy is lensectomy (phakic eyes) and partial removing of the anterior vitreous and a peripheral sector of lens capsule combined with an iridectomy. This is easily performed with the vitrector via pars plana. CONCLUSIONS: Ultrasoundbiomicroscopy starts to confirm the theories on ciliary block glaucoma and allows to assess the different modes of treatment. The most successful treatment is lens extraction and partial vitreo-capsulo-iridectomy via pars plana.

Aged↗
PubMed1999

[Transpupillary thermotherapy of choroidal melanoma].

PURPOSE: The purpose of this report is to evaluate the efficacy of transpupillary thermotherapy (TTT) to treat choroidal melanoma. PATIENTS AND METHOD: 17 patients with choroidal melanoma were treated, 6 patients with small tumors close to posterior pole received TTT only 11 patients were treated simultaneously with TTT and Ru 106 brachytherapy. To perform TTT a diode laser with a beam diameter of 1.5 to 3 millimeters was used. Exposure time ranged from 60 to 90 seconds until a light grey appearance of the retinal surface was reached. Follow-up examinations were performed at 1-month intervals. If the tumor was partially regressed additional TTT was performed to reach the endpoint of a chorioretinal scar. RESULTS: All tumors exhibited a reduction of tumor height in a mean follow-up period of 14.25 months. Side effects were minimal. CONCLUSIONS: Treatment with TTT may be useful as a complementary modality to brachytherapy. A longer follow-up time is necessary for final evaluation.

Adult↗
PubMed1999

Chromatographic properties of the ion-exclusion column IonPac ICE-AS6 and application in environmental analysis. Part I: Chromatographic properties.

The chromatographic performance of the Dionex IonPac ICE-AS6 ion exclusion column is investigated. Therefore, capacity factors, efficiency, peak symmetry, resolution, and selectivity are determined for various mono- and polyfunctional aliphatic carboxylic acids under selected chromatographic conditions. Except for the stronger acids (pKa1 < 3.75), the highest chromatographic efficiency is achieved at a column temperature of 40 or 50 degrees C, and peak shape is found to be optimal at approximately 60 degrees C. The separation of the stronger acids is favored by an eluent pH below 3.0 and column temperatures below 40 degrees C. The maximal effective plate numbers range between 126 (tartronic acid) and 6380 (4-oxovaleric acid). Hydroxy-substituted acids are less retained and less influenced by temperature changes than the unsubstituted compounds. It is estimated that size exclusion effects take part in the separation of aldonic acids. The addition of 1% isopropanol to the acidic eluent increases the chromatographic efficiency generally, whereas higher concentrations reduce the retention of several acids drastically.

Acids↗
PubMed1999

[Alteration of radiation-induced hematotoxicity by amifostine (ethyol)].

BACKGROUND: Radiotherapy--even of small volumes--can decrease leukocyte counts. We examined whether the radio-protector amifostine can reduce this hematotoxicity. PATIENTS AND METHODS: Twenty-six patients (Table 1) undergoing radiotherapy for squamous cell carcinoma of the head and neck were evaluated. All were given 60 (to 70) Gy 5 x 2 Gy per week in standard radiation techniques. Thirteen patients are randomized to receive 200 mg/m2 amifostine i.v., 30 minutes before radiation. Blood counts and differentials were determined before, during and following radiotherapy. Differences of these parameters are calculated and compared by t-test. RESULTS: The blood hemoglobin and the thrombocyte levels did not change during the radiotherapy course, neither for the amifostine treated, nor the control patients. Similarly the leukocyte counts of amifostine treated patients did not change during irradiation. The control patients, however, had a decrease of leukocytes from 8.4 to 6.0 x 10(3)/microliter, p = 0.03 (Table 2), and the reduction of the neutrophilic granulocyte count was more impressive for these patients. CONCLUSION: In this explorative study amifostine diminished radiation induced leukocyte toxicity.

Amifostine↗