Search PubMed⌕ Search

Biomedical subjects

K Fischer

Publications and source records attributed to K Fischer.

At least 91 records · Page 5Linked to original sources
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↗
PubMed1999

['Microbial air pollutants'. Emission sources and preventive measures].

Already in the planning or monitoring phase, measures have to be realized for the reduction in emissions of bio-aerosols in biological waste treatment plants. For this purpose, operation-related measures (in open and partially closed plants) and technology-related measures (in closed plants with automatic ventilation) can be taken. A survey on the currently feasible measures for reduction is submitted. The realization has to be adapted to the individual site and type of plant. An enormous demand for examinations is envisaged in order to enable a qualified assessment of the emission behaviour of diverse waste air systems or process steps.

Air Microbiology↗
PubMed1998

Coronary-artery stenting compared with balloon angioplasty for restenosis after initial balloon angioplasty. Restenosis Stent Study Group.

BACKGROUND: Intracoronary stenting reduces the rate of restenosis after angioplasty in patients with new coronary lesions. We conducted a prospective, randomized, multicenter study to determine whether intracoronary stenting, as compared with standard balloon angioplasty, reduces the recurrence of luminal narrowing in restenotic lesions. METHODS: A total of 383 patients who had undergone at least one balloon angioplasty and who had clinical and angiographic evidence of restenosis after the procedure were randomly assigned to undergo standard balloon angioplasty (192 patients) or intracoronary stenting with a Palmaz-Schatz stent (191 patients). The primary end point was angiographic evidence of restenosis (defined as stenosis of more than 50 percent of the luminal diameter) at six months. The secondary end points were death, Q-wave myocardial infarction, bypass surgery, and revascularization of the target vessel. RESULTS: The rate of restenosis was significantly higher in the angioplasty group than in the stent group (32 percent as compared with 18 percent, P= 0.03). Revascularization of the target vessel at six months was required in 27 percent of the angioplasty group but in only 10 percent of the stent group (P=0.001). This difference resulted from a smaller mean (+/-SD) minimal luminal diameter in the angioplasty group (1.85+/-0.56 mm) than in the stent group (2.04+/-0.66 mm), with a mean difference of 0.19 mm (P=0.01) at follow-up. Subacute thrombosis occurred in 0.6 percent of the angioplasty group and in 3.9 percent of the stent group. The rate of event-free survival at 250 days was 72 percent in the angioplasty group and 84 percent in the stent group (P=0.04). CONCLUSIONS: Elective coronary stenting was effective in the treatment of restenosis after balloon angioplasty. Stenting resulted in a lower rate of recurrent stenosis despite a higher incidence of subacute thrombosis.

Aged↗
PubMed1998

stevor and rif are Plasmodium falciparum multicopy gene families which potentially encode variant antigens.

Several multicopy gene families have been described in Plasmodium falciparum, including the var genes that code for the variant surface antigen PfEMP1, the stevor family of subtelomeric open reading frames and the rif interspersed repetitive elements. This report documents the chromosomal location of stevor genes, their transcription and characteristics of the deduced protein. On 14 chromosomes, 34 stevor copies were identified from the Dd2 parasite line. Most are in subtelomeric regions within 50 kb of the telomere. stevor genes are located close to var genes and rij. All stevor genes sequenced had two exons: a short exon 1 encoding a start codon and a transmembrane domain; exon 2 encoding for the remainder of the approximately 30 kDa protein and including two more transmembrane segments. A similar structure was found for copies of rif and its predicted protein. In both STEVOR and RIF proteins, a highly polymorphic region is predicted to be a loop on the outer side of the membrane. We propose that stevor and rif are members of a larger superfamily. The number of copies of stevor and rif, their location close to the var genes, their extreme polymorphism and the predicted structure of the proteins suggest that stevor and rif code for variant surface antigens.

Amino Acid Sequence↗