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K Baier

Publications and source records attributed to K Baier.

At least 37 records · Page 2Linked to original sources
PubMed1999

A male gametophyte-specific monosaccharide transporter in Arabidopsis.

The AtSTP2 gene (sugar transport protein 2) of Arabidopsis thaliana encodes a high affinity, low specificity monosaccharide carrier that can transport a number of hexoses and pentoses at similar rates. AtSTP2 has 12 putative transmembrane helices and a molecular mass of 55.0 kDa. AtSTP2 expression was localized in AtSTP2 promoter-beta-glucuronidase (GUS) Arabidopsis plants showing AtSTP2-driven GUS activity during pollen maturation and also in germinating pollen. Immunohistochemical studies with anti-AtSTP2 antiserum as well as RNA in situ hybridization analyses modified these results and showed that AtSTP2 expression is confined to the early stages of gametophyte development. Both AtSTP2 mRNA and AtSTP2 protein are first seen at the time of beginning callose degradation and microspore release from the tetrades. AtSTP2 mRNA and AtSTP2 protein are no longer detected after the mitotic divisions and the formation of the trinucleate gametophyte. No AtSTP2 mRNA or AtSTP2 protein is seen in fully developed or germinating pollen. The putative role of AtSTP2 in the uptake of glucose units resulting from callose degradation during pollen maturation is discussed.

Amino Acid Sequence↗
PubMed1999

Tumor volume and local control in primary radiotherapy of nasopharyngeal carcinoma.

An investigation of the effect of tumor volume and total dose on local control following primary radiotherapy for nasopharyngeal carcinoma was carried out in order to estimate the radiation dose necessary to control a specific tumor volume. Between 1983 and 1996 a total of 104 patients underwent radiation therapy for nasopharyngeal carcinoma at the Department of Radiation Oncology of the University of Wuerzburg. Total doses of between 8 and 80 Gy (5 fractions per week) were administered. Complete CT-data on primary tumor size, total tumor dose (calculated by 3D- or quasi 3D-CT-based radiation planning computer) and on local control status in the follow-up period were available for 63 patients. Lymph node metastases were present in 38 of these patients and they were also entered into the study. Thus this study is based on a total of 101 tumor regions. A Poisson probability-based model was used for calculating the dose-response relationship. Assuming a correlation between tumor volume and the total dose necessary to obtain local control, the individual tumor volumes were rescaled to a 1 ml volume by introducing a volume-dependent modification factor for the applied dose, in order to eliminate the influence of different individual tumor volumes. All dose values given are based on a fractionation scheme of 2 Gy single dose, 5 fractions per week. Nineteen tumors and 11 lymph nodes were considered locally uncontrolled or recurrent. Without dose-volume modification, a weak dose-response correlation was found and a typical shallow dose-response curve was calculated with a 50% response dose (RD50) of 60.2 Gy and a normalized dose-response gradient (gamma50) of 3.2+/-0.62. After dose-volume modification and rescaling to a 1 ml tumor volume, a steep dose-response curve with an RD50 of 40.9 Gy and gamma50 of 8.2. was found. Tumor volume is a very important factor influencing local control in nasopharyngeal carcinoma. The rescaling procedure to a reference volume of 1 ml used in this study revealed a very steep dose-response relationship. This result suggests that the clinically observed smooth dose-response relationships may be explained by interindividual tumor volume heterogeneity. The additional dose necessary to control a tumor of the double volume is close to 5 Gy. With a total dose of 72 Gy (5x2 Gy/week), tumor volumes larger than 64 ml are unlikely to be controlled.

Carcinoma↗
PubMed1999

Frequency of cytokine-producing T cells in patients of different age groups with Plasmodium falciparum malaria.

The frequency of cytokine-producing T cells was assessed in patients of different age groups (29 infants, aged 1-5 years; 30 schoolchildren, aged 6-14 years; 26 adults, aged >15 years) with acute Plasmodium falciparum malaria from Gabon. By using flow cytometry for the intracellular detection of cytokines, a striking expansion was seen, in adults compared with children, of CD4+ and CD8+ T cells with the following profiles of type 1 cytokine production: interleukin (IL)-2-/interferon (IFN)-gamma+, IL-2+/IFN-gamma+, and IL-2+/IFN-gamma-. Patients with hyperparasitemia had a significantly lower frequency of IL-2-/IFN-gamma+ CD4+ cells. Type 2 cytokine expression (IL-4+/IFN-gamma-, IL-13+/IFN-gamma-) and type 0 cytokine expression (IL-4+/IFN-gamma+, IL-13+/IFN-gamma+) were also increased in adults within the CD4+ subset. Frequencies of IL-5+/IL-4+, IL-10+/IFN-gamma-, and IL-10+/IFN-gamma+ cells were similar in all groups. The increased frequency of both type 1 and type 2 cytokine-producing T cells in adults is likely to be of significance in the protection against P. falciparum malaria.

Acute Disease↗
PubMed1999

Regulatory effects of 1alpha,25-dihydroxyvitamin D3 on the cytokine production of human peripheral blood lymphocytes.

We studied the possible regulatory effects of 1alpha,25-dihydroxyvitamin D3 [1alpha,25-(OH)2D3] on cytokine production and differentiation of subsets of CD4+ [T helper 1 (Th1) and Th2] and CD8+ [T cytotoxic 1 (Tc1) and Tc2] lymphocytes at the single cell level. PBMC from healthy donors were cultured with or without 1alpha,25-(OH)2D3 for up to 21 days. On days 0, 7, 14, and 21, the percentage of cytokine-producing T lymphocytes was analyzed by intracellular cytokine detection with mAb and flow cytometry. Simultaneous staining for cell surface markers allowed discrimination of CD4+ and CD8+ T cell subsets. After culture with 1alpha,25-(OH)2D3 (10(-8) mol/L), no significant effects on the proportion of interferon-gamma (IFNgamma)- or interleukin-4 (IL-4)-producing cells were detected, whereas reduced frequencies of IL-2-producing cells in the CD4+ as well as in the CD8+ population were found. An increase in the low percentage of CD4+ and CD8+ T cells producing the Th2 cytokine IL-13 was noticed. Most interestingly, IL-6-producing CD4+ and CD8+ T cells could only be detected in cultures with 1alpha,25-(OH)2D3, reaching a plateau after 14 days. The percentage of IL-6-producing T cells induced by 1alpha,25-(OH)2D3 after a given time period remained stable for at least 7 weeks. Studies of cytokine coexpression revealed that about 70% of IL-6-producing CD4+ and CD8+ cells were also positive for IL-2, but more than 90% were negative for IFNgamma, IL-4, or IL-13, respectively. This suggests that the IL-6-producing population does not match the Th1/Tc1-like (IFNgamma+) or Th2/Tc2-like (IL-4+ or IL-13+) subset. The influence of 1alpha,25-(OH)2D3 on cytokine production by lymphocytes is probably an important point of intersection between the endocrine and the immune system.

Adult↗
PubMed1999

Increased frequency of Th2-type cytokine-producing T cells in microfilaremic loiasis.

The frequency of cytokine-producing peripheral blood mononuclear cells was assessed in 28 subjects with microfilaremic loiasis and in 14 amicrofilaremic individuals. In addition, a subgroup of seven microfilaremic individuals coinfected with Plasmodium malariae was evaluated. By using flow cytometry for the intracellular detection of cytokines, a more pronounced T helper (Th)2 cell-type response with the expansion of interleukin (IL)-4, IL-10, and IL-13 expressing CD4+ cells in the microfilaremic compared with the amicrofilaremic group was noted. Expression of IL-5 was equivalent in both groups as was the frequency of Th2-type cytokines expressing CD8+ cells and of Th1-type cytokines (interferon [IFN]-gamma, IL-2, IFN-gamma/IL-2) producing CD4+ and CD8+ cells. Th0-type cytokine-expressing cells, represented by IL-4/IFN-gamma, IL-10/IFN-gamma, and IL-13/IFN-gamma, were equally distributed within groups. Coinfection of P. malariae did not significantly alter the cytokine expression compared with microfilaremic individuals without P. malariae infections. By identifying a large panel of cytokine-producing T cell subpopulations, a Th2-driven immune response in microfilaremic Loa loa patients was noted.

Adult↗
PubMed1999

Frequency of cytokine-producing CD4-CD8- peripheral blood mononuclear cells in patients with Plasmodium falciparum malaria.

The frequency of cytokine-producing CD4-/CD8- mononuclear cells was assessed in patients of different age groups (29 infants, aged 1-5 years; 30 schoolchildren, aged 6-14 years, 26 adults, aged > 15 years) with acute Plasmodium falciparum malaria, from Gabon. Fifteen patients were followed up before antimalarial treatment (day 0), during parasite clearance (day 3) and after resolution of parasitemia (day 10). By using flow cytometry for intracellular detection of cytokines, a striking expansion of CD4-/CD8- cells producing the type 1 cytokines interleukin (IL)-2-/interferon (IFN)-gamma+, IL-2+/IFN-gamma+ and IL-2+/IFN-gamma- was observed in adults as compared with children. Type 2 cytokine expression (IL-4+/IFN-gamma-, IL-13+/IFN-gamma-) and type 0 cells (IL-4+/IFN-gamma+, IL-13+/IFN-gamma+) were not significantly different between the three age groups. Patients with severe malaria had a significantly increased frequency of type 2 cytokine-producing CD4-/CD8- cells. Drug-induced clearance of parasitemia was characterized by a decrease of IL-2+/IFN-gamma- and type 2 cytokine expressing CD4-/CD8- cells and by a gradual increase of IL-10+/IFN-gamma- expression. The type 1/type 2 dichotomy observed within the CD4-/CD8- cell population is likely to be of significance in the host response against P. falciparum malaria.

Adolescent↗
PubMed1998

[3D-Ct-planned interstitial HDR brachytherapy + percutaneous irradiation and chemotherapy in inoperable pancreatic carcinoma. Methods and clinical outcome].

PURPOSE: Clinical experiences in interstitial 192-iridium HDR brachytherapy for the treatment of unresectable pancreatic carcinoma are presented. Brachytherapy has been used as boost irradiation in a multimodality treatment concept together with external radiotherapy and simultaneous chemotherapy. Practicability during clinical routine, tolerability and toxicity of treatment are investigated. PATIENTS AND METHODS: Nineteen patients (9 female, 10 male, median age 67 years) with unresectable carcinoma of the pancreas have been treated with interstitial brachytherapy. Distribution according to UICC stages showed 4, 10 and 5 patients in stage II to IV respectively. In all cases afterloading technique with 192-iridium in HDR-modus was used. A total dose of 10 to 34 Gy to the reference isodose was delivered (single dose 1.88 to 5 Gy, median 2.5 Gy). Brachytherapy was followed by external radiotherapy, delivering an additional dose of 40 to 58 Gy. Nine patients received simultaneous chemotherapy (5-fluorouracil, leucovorin). Treatment planning was performed based on CT scans, allowing spatial correlation of isodose curves to the patient's anatomy. RESULTS: Median survival time was 6 months. A trend of lower survival rates with advanced stage of disease (median survival stage IV 4 months, stage II and III 6.5 months) was seen. Local control rate was 70%. Brachytherapy treatment was well tolerated, severe acute side effects were not observed. One patient developed pancreatic fistulae 4 months and 1 patient a gastric ulcer 7 months after treatment. Pain release was achieved in all patients. CONCLUSIONS: 192-iridium HDR-brachytherapy is an effective tool in the treatment of unresectable pancreatic carcinoma with a high rate of local control and a low rate of side effects and is comparable IORT or seed implantation.

Adenocarcinoma↗
PubMed1998

Reciprocal regulation of Th1- and Th2-cytokine-producing T cells during clearance of parasitemia in Plasmodium falciparum malaria.

Flow cytometry for the intracellular detection of T-cell cytokines was performed for 15 Gabonese patients during acute uncomplicated Plasmodium falciparum malaria. A striking expansion of CD4(+) and CD8(+) T cells producing gamma interferon (IFN-gamma) was found during drug-induced clearance of parasitemia, paralleled by a decrease of interleukin-2 (IL-2) production. The frequency of IL-4- and IL-13-producing CD4(+) cells gradually decreased, whereas the frequency of T cells producing IL-2(+)-IFN-gamma+, IL-4(-)-IL-5(+), and IL-4(+)-IL-5(+) cytokines as well as IL-4(+)-IFN-gamma+ and IL-13(+)-IFN-gamma+ cytokines was not significantly altered. The capacity for IL-10 production within the CD4(+) subset increased due to an expansion of both IL-10(+)-IFN-gamma- and IL-10(+)-IFN-gamma+ cytokine-expressing cells. Thus, a more pronounced Th2-driven immune response during acute untreated P. falciparum infection with a shift towards Th1 responsiveness induced by parasite clearance is suggested.

Acute Disease↗
PubMed1998

Reduction of fecal contamination of street-vended beverages in Guatemala by a simple system for water purification and storage, handwashing, and beverage storage.

Street-vended foods and beverages, an integral part of urban economies in the developing world, have been implicated in cholera transmission in Latin America. To improve the microbiologic quality of market-vended beverages in Guatemala, we tested a simple system consisting of dilute bleach (4.95% free available chlorine) for water purification, narrow-mouth plastic vessels with spigots for disinfecting and storing water and for preparing and storing beverages, handwashing soap, and education in using the system. We conducted a randomized controlled intervention trial among 41 vendors who received the intervention and 42 control vendors, comparing total and fecal coliform bacteria and Escherichia coli contamination of market-vended beverages, stored water, and vendors' hands. Samples were obtained at baseline and at each of six weekly follow-up visits. At baseline, fecal coliform bacteria were found in 40 (48%) market-vended beverages and E. coli in 14 (17%). When compared with samples from control vendors, a significant decrease in total coliform (P < 0.001) and fecal coliform (P < 0.001) bacteria in samples of stored water and beverages sold by intervention vendors was observed over the course of the study. The vessel system was well accepted by vendors. This simple inexpensive system consisting of hypochlorite disinfectant, plastic vessels, soap, and education can significantly reduce fecal contamination of market-vended beverages.

Adolescent↗
PubMed1997

Cell surface characterization of T lymphocytes and allergen-specific T cell clones: correlation of CD26 expression with T(H1) subsets.

To evaluate the possibility of using surface molecules as markers for human T helper cell subsets, we studied the expression of surface molecules on T cell clones (TCCs) specific for the major birch pollen allergen, Bet v 1. No difference in the expression of the respective receptors for interferon-gamma (IFN-gamma), IL-4, IL-6, or IL-10 could be detected on T(H) subsets, nor did CD25 expression (IL-2R alpha-chain) differ significantly. However, high expression of CD26 antigen (dipeptidyl peptidase IV) correlated with a T(H1)/T(H0)-like phenotype, whereas T(H2)-like clones displayed a lower expression of CD26 antigen. Comparing cytokine production and CD26 expression simultaneously, we found a correlation between the IL-4/IFN-gamma ratio and the density of CD26 per cell. We could show that the amount of IL-4 secretion, and not of IFN-gamma secretion, was responsible for this correlation. To evaluate whether CD26 antigen expression is regulated by stimuli inducing a T(H1)- or T(H2)-like phenotype, peripheral blood mononuclear cells (PBMC) were cultured in the presence of IL-4, IFN-gamma, and IL-12, respectively. Incubation with IL-4 led to T cells with a T(H2)-like cytokine pattern and a significantly lower expression of CD26; IFN-gamma and IL-12 led to a T(H1) shift associated with an increased expression of CD26 on CD4+ T cells. By means of intracellular cytokine detection we analyzed expression of CD26 on CD4+ PBMC stimulated to produce IFN-gamma or IL-4 on a single cell level. All activated, cytokine-producing CD4+ T cells expressed CD26, but the increase in CD26 expression was higher in cells producing IFN-gamma. These data suggest that regulation of CD26 cell surface expression correlates with the production of T(H1)-like cytokines.

Allergens↗
PubMed1996

Evidence for propeptide-assisted folding of the calcium-dependent protease of the cyanobacterium Anabaena.

The Ca(2+)-dependent protease of the cyanobacterium Anabaena variabilis is a cytoplasmic enzyme with a substrate specificity like trypsin. Its previously published DNA sequence [Maldener, I., Lockau, W., Cai, Y. & Wolk, C. P. (1991) Mol. Gen. Genet. 225, 113-120] contained a sequencing error. Here we report the corrected sequence which shows, that the Ca(2+)-protease belongs to the family of subtilases (subtilisin-like serine proteases). Consistent with its cytoplasmic localization, a pre-sequence is not found. The enzyme is produced as a precursor with a large amino-terminal propeptide. Expression of the pro-region and mature region (protease domain) in Escherichia coli cells in trans demonstrates that formation of the active enzyme requires the propeptide. The results demonstrate that propeptide-assisted protein folding also occurs with cytoplasmic enzymes, in support of the hypothesis that this mechanism is a widespread phenomenon.

Amino Acid Sequence↗
PubMed1995

Hydrocortisone enhances total IgE levels--but not the synthesis of allergen-specific IgE--in a monocyte-dependent manner.

Recently, hydrocortisone (HC), when combined with human IL-4, has been reported to increase IgE levels in supernatants (SN) of in vitro cultured leucocytes. In this study we investigated the influence of HC on allergen-specific IgE synthesis. Moreover, we examined the relevance of different cell types in this respect. Peripheral blood mononuclear cells (PBMC), T-cell depleted PBMC, CD14-depleted PBMC and highly purified B cells from 10 allergic (birch pollen and/or grass pollen) patients and five non-allergic individuals were investigated. The cells were incubated with HC and/or recombinant human IL-4 (rIL-4) for 8 days. A considerable increase of total IgE was observed in HC/rIL-4-stimulated cultures compared with rIL-4 alone, HC alone or non-stimulated cultures. We demonstrate that this effect depends on the presence of monocytes in in vitro cultures. These results were seen in every experiment, irrespective of healthy or atopic state of the blood donor. The increase of IgE could not be attributed to a rise of birch pollen-and/or grass pollen-specific IgE in patients allergic to these allergens, as shown by IgE-immunoblot. Radio-allergosorbent test (RAST) investigations of HC/rIL-4-stimulated cells cultures from allergic and non-allergic patients confirmed that HC/rIL-4-induced elevated IgE production was also not due to increased production of IgE, specific for important aero-allergens (pollens, house dust mite or animal dander). Therefore we conclude that newly synthesized IgE is not specific for allergens, but that sequential isotype switching in human B cells leads to increased polyclonal IgE production.

Allergens↗
PubMed1994

Sugar transport across the plasma membranes of higher plants.

The fluxes of carbohydrates across the plasma membranes of higher-plant cells are catalysed mainly by monosaccharide and disaccharide-H+ symporters. cDNAs encoding these different transporters have been cloned recently and the functions and properties of the encoded proteins have been studied extensively in heterologous expression systems. Several of the proteins have been identified biochemically in these expression systems and their location in plants has been shown immunohistochemically or with transgenic plants which were transformed with reporter genes, expressed under the control of the promoters of individual transporter genes. In this paper we summarize the current knowledge on the molecular biology and biochemistry of higher-plant sugar transport proteins.

Biological Transport↗
PubMed1994

[The multisegmental electron irradiation of the chest wall following ablative therapy of breast cancer].

PURPOSE: The paper describes the clinical aspects of postoperative irradiation of breast cancer using electron arc technique at the chest wall. The value of the treatment is assessed by long-term results concerning the rate of local recurrences and side effects. The advantages of the procedure are described with regard to physical and technical aspects. PATIENTS AND METHODS: After mastectomy, 117 patients underwent and adjuvant radiotherapy of the chest wall by multisegmental electron rotation technique with energies between 4 and 14 MeV. The number and angular range of the segments as well as the energy of the electrons depended on the peculiar thickness of the chest wall. 25 times 2 Gy were applied within five weeks. The treatment planning is based on a patient model constructed from five CT-slices at least. RESULTS: In four cases (3.4%) a local relapse and in one case (0.9%) a relapse in supraclavicular lymphatics was found. The recurrences appeared after an average period of 32 months. The mean observation time was 70 months. In 37 women (32%) distant metastases were seen after 29 months on an average. The five-year survival rate is 73.5%. CONCLUSION: In comparison to usual techniques using photons the described method shows a more homogeneous dose distribution to the chest wall and a reduction of lung radiation exposure. The clinical result of this dose adaptation to the treatment volume is a lower rate of local relapses and of side effects, inclusive late reactions. It can be suggested that the efficiency of the procedure will be ameliorated in future using special electron compensators. This will result in a more favorable adaptation of dose distribution to the anatomical situation in regard to the cranio-caudal profile.

Adult↗
PubMed1992

[Population genetic Hae III/RFLP and HLA-DQ-alpha data of a Caucasian population sample in Switzerland].

DNA from unrelated individuals (Caucasians; n = 200-271) from Switzerland were digested with Hae III and successively hybridized to the DNA probes D1S7, D2S44, D4S139, D10S28, D14S13, D17S26 and D17S79. An allele frequency distribution was determined for each locus. Furthermore, from the same individuals (n = 200) after amplification of DNA the allele and genotype frequencies at the HLA-DQ alpha locus were determined. The allele frequency distribution in Swiss Caucasians is statistically similar to American Caucasian population samples. In criminal cases a DNA-profile derived from four single-locus probes always leads to a very high value of discrimination and in paternity testing the probability of paternity always exceeds 99.9% regardless to the reference population used for biostatistical evaluation. Therefore for use in forensic analysis and paternity testing pooled caucasian databases might be used for the determination of the frequency of occurrence of a DNA-profile.

Alleles↗