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Biomedical subjects

K Walter

Publications and source records attributed to K Walter.

At least 19 recordsLinked to original sources
PubMed2006

Variants in Apaf-1 segregating with major depression promote apoptosome function.

APAF1, encoding the protein apoptosis protease activating factor 1 (Apaf-1), has recently been established as a chromosome 12 gene conferring predisposition to major depression in humans. The molecular phenotypes of Apaf-1 variants were determined by in vitro reconstruction of the apoptosome complex in which Apaf-1 activates caspase 9 and thus initiates a cascade of proteolytic events leading to apoptotic destruction of the cell. Cellular phenotypes were measured using a yeast heterologous expression assay in which human Apaf-1 and other proteins necessary to constitute a functional apoptotic pathway were overexpressed. Apaf-1 variants encoded by APAF1 alleles that segregate with major depression in families linked to chromosome 12 shared a common gain-of-function phenotype in both assay systems. In contrast, other Apaf-1 variants showed neutral or loss-of-function phenotypes. The depression-associated alleles thus have a common phenotype that is distinct from that of non-associated variants. This result suggests an etiologic role for enhanced apoptosis in major depression.

Alleles↗
PubMed2005

[Organization and role of the German public health service].

The article describes the organization and role of the public health service in Germany. Health is not a federal but a state issue; sta-te health regulations are subject to state legislation. The role of the public health service may therefore differ among the federal sta-tes of Germany. In recent years there ha-ve been considerable changes in the main features of the role of the public health ser-vice. Prevention and health reporting have become top issues, as well as hygiene, control of epidemics, medical certificates, and physical and dental examinations for schoolchildren. The public health service has developed into an up-to-date and customer-focused organization. Using modern management methods and employing well-trained doctors and other highly skilled health professionals, the public health service will full-fill its role in working for the benefit of the citizens of Germany providing the necessary resources are available. The generational change in the public health service will be marked in the coming years, especially in the east of Germany. Many physicians will reach retirement age and need replacing. Physicians with postgraduate professional education in public health are rare; training in this area of expertise must be fostered.

Education, Medical, Graduate↗
PubMed2004

[Transparency in patient care -- survey of bedsores on communal level to promote quality assurance].

The medical diagnosis of bedsores often applies to open wounds. These wounds are caused by constant pressure to the skin of seniors who cannot change their position in bed or wheelchair without help. In severe cases these wounds extend through all layers of the skin with involvement of muscle and underlying bone. These ulcers can be very painful, so the mobility and quality of life of seniors is thoroughly reduced. Treatment of ulcers costs annually millions of Euro in Germany alone. Primary prevention of bedsores has not yet been established neither in Germany nor in Europe. The first step to improve the situation in a scientific manner has been to set up a comparable database. In order to change that, the German community of Ostalbkreis (part of the German Federal state of Baden-Wurttemberg) developed a process of nursing quality assurance as a project of the local agenda 21, initiated and supported by the health office of the community. Annual networked and anonymous survey from 2001 to 2003, each lasting three months every year, proved that the rate of non stratified prevalence could be reduced. For example the rate of all day spent with bedsores within the community could be reduced from 1.96 % in 2001, to 1.74 % in 2002 and finally to 1.62 % in 2003. During the survey as an additional bonus cooperation of community-organized nursing was optimised and quality assurance in nursing became a pole position of the community. During the QM-process a software was developed to process the survey: it is internet-based, published in the nursing-guide of Ostalbkreis, easy to manage and to establish in any nursing institution or community.

Aged↗
PubMed2003

Complement component C7 deficiency in a Spanish family.

Different genetic mutations have been described in complement component C7 deficiency, a molecular defect which is clinically associated with an increased susceptibility to neisserial recurrent infections, although some cases remain asymptomatic. In this work we report the genetic bases of C7 deficiency in one Spanish family. Exon-specific PCR and sequencing revealed a novel point mutation at nucleotide 615 (exon 6) leading to a stop codon (UGG to UGA) in the patient, his mother, and sister. This transversion causes the premature truncation of the C7 protein (W183X). Additionally, we detected a missense mutation at position 1135 (exon 9) located in the first nucleotide of the codon GGG (CGG), resulting in an amino acid change (G357R) in the patient, his father, as well as in his sister. This latter mutation had been previously described in individuals from Moroccan Sephardic Jewish ancestry. Since both heterozygous mutations were found in the patient as well as in his asymptomatic sister, we analyse other meningococcal defence mechanisms such as polymorphisms of the opsonin receptors on polymorphonuclear cells. Results showed that the patient and his sister bore identical combinations of FcgammaRIIA-H/R131 and FcgammaRIIIB-NA1/2 allotypes. Our results provide further evidence that the molecular pathogenesis of C7 deficiency as well as susceptibility to meningococcal disease are heterogeneous, since different families carry different molecular defects, although many of the C7 defects appear to be homogeneous in individuals from certain geographical areas. The missense mutation G357R would make an interesting topic of analysis with regard to meningococcal disease susceptibility in the Spanish population.

Base Sequence↗
PubMed2003

Application of techniques for sperm selection in fresh and frozen-thawed stallion semen.

The objective of this research was to improve the techniques in processing chilled and frozen-thawed horse semen. In a preliminary experiment (Exp. I), different techniques for sperm selection and preparation [Swim-up, Glass wool (GW) filtration, Glass wool Sephadex (GWS) filtration; Percoll] were tested for their suitability for equine spermatozoa and results were compared with the routine procedure by dilution (Exp. I). In the main experiment (Exp. II), two sperm preparation techniques (GWS, Leucosorb) refering to the results of Exp. I and a previous study of our group (Pferdcheilkunde 1996 12, 773) were selected for processing complete ejaculates either for cooled-storage or cryopreservation. In a third experiment (Exp. III), pregnancy rates from inseminations with semen processed according to the techniques tested in Exp. II were compared with those obtained with semen processed according to routine procedures. In Exp. I (six stallions, six ejaculates/stallion), between 48 and 92% of spermatozoa were lost following the different sperm selection procedures (p < 0.05). Preparation of sperm increased percentage of progressively motile spermatozoa (pms) [Swim-up, GW, GWS vs dilution, Percoll (p < 0.05)] and decreased percentage of sperm head abnormalities [Swim-up, GW, GWS vs dilution, Percoll (p < 0.05)] probably by not improving the quality of individual cells, but by elimination of spermatozoa of inferior quality. In Exp. II (eight stallions, three ejaculates/stallion) Leucosorb and GWS procedures allowed the filtration of large volumes (extended ejaculates) for routine laboratory practice. GWS and Leucosorb filtration resulted in increased motility, membrane integrity and sperm viability after storage of spermatozoa until 48 h at +5 degrees C when compared with control (diluted) and centrifuged semen (p < 0.05). Significantly more spermatozoa were recovered after centrifugation (87.8 +/- 15.4%) compared with GWS (63.5 +/- 18.6%) and Leucosorb filtration (53.6 +/- 22.3%). GWS or Leucosorb procedure resulted in successful cryopreservation of stallion semen without centrifugation for removal of seminal plasma. The per cycle conception rate of inseminated mares using 200 x 106 pms transferred within 8 h after collection of semen was not affected by GWS filtration or Leucosorb separation when compared with centrifugation (n.s.; Exp. III). In conclusion, GWS and Leucosorb filtration results in the improvement of semen quality and should be considered as a method for stallion semen processing. Additional studies are needed for the evaluation of potentially higher fertilizing ability of stallion spermatozoa separated by techniques for sperm selection.

Animals↗
PubMed2003

Clinical significance of anti-multiple nuclear dots/Sp100 autoantibodies.

BACKGROUND: Autoantibodies against discrete variable-sized dots observed in HEp2 cells by indirect immunofluorescence (IIF) test, called multiple nuclear dots (MND), have been closely associated with primary biliary cirrhosis (PBC). Some authors have argued that this antibody is also present in connective tissue diseases or liver diseases other than PBC as autoimmune chronic active hepatitis, particularly of the cholestatic type. We studied an unselected group of patients routinely tested for autoantibodies and positive for the MND pattern and tried to establish the correlation between the presence of this antibody and their diagnosis. METHODS: A commercial ELISA test, using a recombinant 26 kD truncated sequence of the Sp100 protein, corresponding to an immunodominant molecular region, was used to assess the clinical correlation of these autoantibodies in 110 patients showing an anti-MND immunofluorescence pattern. RESULTS: One-hundred-and-ten patients were MND positive by IIF. Of these, 100 were Sp100 positive by ELISA. In the Sp100 positive group, 34 had a diagnosis of PBC (30 definite and 4 suspected) while 15 patients had a non-PBC hepatopathy. Unexpectedly, 13 of the MND/Sp100 positive pattern corresponded to systemic lupus erythematosus (SLE) patients and 5 cases to collagen diseases. Another divergence with previous reports was that 34 of the positive patients showed very heterogeneous clinical pictures, different from hepatopathies or collagen diseases. CONCLUSIONS: Anti-Sp100 antibodies can be found in many clinical conditions. Testing for MND/Sp100 positivity is useful for the diagnosis of PBC, but only when the right clinical context is present. Other diseases cannot be excluded in first line SLE.

Antigens, Nuclear↗
PubMed2002

X-ray crystallographic structure of ABT-378 (lopinavir) bound to HIV-1 protease.

The crystal structure of ABT-378 (lopinavir), bound to the active site of HIV-1 protease is described. A comparison with crystal structures of ritonavir, A-78791, and BILA-2450 shows some analogous features with previous reported compounds. A cyclic urea unit in the P(2) position of ABT-378 is novel and makes two bidentate hydrogen bonds with Asp 29 of HIV-1 protease. In addition, a previously unreported shift in the Gly 48 carbonyl position is observed. A discussion of the structural features responsible for its high potency against wild-type HIV protease is given along with an analysis of the effect of active site mutations on potency in in vitro assays.

Binding Sites↗
PubMed2002

[Expertising according to the federal German social welfare legislation and child and adolescent welfare laws by public health offices--results of an inquiry].

Between December 2000 and February 2001 a survey among public health offices was conducted on the practice of expert reports on recipients of income support. More than 50 % (232) of the German public health offices participated; they carried out 164.000 of these reports in 1999. The analysis of the data shows considerable differences between the states (Bundesländer) concerning reasons and practice of expert reports which cannot be explained by a different social structure of population but indicate that quality of orders from Social Services and the work process in Public Health Offices may be inadequate. The findings result in recommendations for social services and public health offices to develop standards and improve quality, which can help to achieve greater equality.

Adolescent↗
PubMed2002

[New avenues to quality assurance--a model project for recording bedsore incidence].

Bedsores can usually be avoided by adequate care and preventive measures. In the context of the local agenda process a local district office (Landratsamt) and inspection units initiated a variety of activities to promote sensitisation in health institutions and contribute to an increase in life quality of the persons concerned. Nearly all nursing care homes, domiciliary services and hospitals participated in a pilot study which was accompanied by the Fraunhofer IAO in Stuttgart. Objectives of the pilot study were to implement internal quality assurance to sensitise for persons the topic and to collect comparable data to achieve benchmarking. Software-tool institutions recorded data on care days, days spent with bedsores according to care level from July till September 01. Major result was that - although institutions had already a decreasing incidence in bedsores since the start of discussing the project - bedsore quotas could be further decreased from 2.15 to 1.84 %.

Aged↗
PubMed2002

[Optimization of radiotherapy planning for non-small cell lung cancer (NSCLC) using 18FDG-PET].

AIM: In recent years, FDG-PET examinations have become more important for problems in oncology, especially in staging of bronchogenic carcinoma. In the retrospective study presented here, the influence of PET on the planning of radiotherapy for patients with non-small-cell lung cancer (NSCLC) was investigated. METHODS: The study involved 39 patients with NSCLC who had been examined by PET for staging. They received radiotherapy on the basis of the anterior/posterior portals including the primary tumour and the mediastinum planned according to CT- and bronchoscopic findings. The results of the PET examination were not considered in initial radiotherapy planning. The portals were retrospectively redefined on the basis of FDG uptake considering the size and localization of the primary tumour; and FDG activities outside the mediastinal part of the portals. RESULTS: In 15 out of 39 patients, the CT/PET-planned portals differed from the CT-planned ones. In most causes (n = 12) the CT/PET field was smaller than the CT field. The median geometric field size of the portals was 179 cm2, after redefinition using PET 166 cm2. In 20 patients with disturbed ventilation caused by the tumour (atelectasis, dystelectosis), a correction of the portal was suggested significantly more frequently than in the other patients (p = 0.03). CONCLUSIONS: Our results demonstrate the synergism of topographical (CT) and metabolic (FDG-PET) information, which could be helpful in planning radiotherapy of bronchial carcinoma, especially for patients with disturbed ventilation.

Carcinoma, Non-Small-Cell Lung↗
PubMed2001

Gestational regulation of the gene expression of C-type natriuretic peptide in mouse reproductive and embryonic tissue.

C-Type natriuretic peptide (CNP) is a vasoactive hormone and the endothelial component of the natriuretic peptide system. We examined the expression of CNP in mouse reproductive organs and embryos at different stages of gestation. Pregnant mice were killed and embryos were dissected on gestational days 9.5, 12.5, 15.5, 18.5 postconceptionem (pc) and at term. Nonpregnant mice were used as controls. Total RNA was isolated from placenta, ovaries, myometrium and from head and trunk of embryos and neonates. CNP-mRNA was quantified by ribonuclease-protection assay (RPA). Uterine CNP-mRNA concentrations increase during pregnancy up to the sevenfold concentration, whereas in the ovaries these levels decrease to 10% compared to nonpregnant controls. In the placenta, a peak of CNP expression has been observed around day 15.5 pc, whereby placenta showed the strongest CNP signals. CNP-mRNA concentrations in embryos are gestational age-dependent with a high level at day 9.5 pc in head and trunk. These results indicate that CNP has a regulatory function in pregnancy and embryonic development.

Animals↗
PubMed2001

Nontruncating APC germ-line mutations and mismatch repair deficiency play a minor role in APC mutation-negative polyposis.

Familial adenomatous polyposis, an autosomal-dominantly inherited colorectal cancer predisposition syndrome, is caused by germ-line mutations in the adenomatous polyposis coli (APC) gene. Despite the use of different screening methods, studies worldwide fail to identify APC mutations in 20-50% of all familial adenomatous polyposis patients (APC mutation-negatives). In this study, missense mutations in the coding region of the APC gene, which would have been missed by the protein truncation test, as well as mutations in the APC promoter and the 3' untranslated region, were determined by the single nucleotide polymorphism discovery assay and direct DNA sequencing in 31 mutation-negative polyposis patients. Seventeen gene alterations were identified, whereof four (12.9%) represent possibly pathogenic germ-line mutations: silent A290T (promoter) and A8822G (3' untranslated region) as well as missense R99W and E1317Q (coding region). The 27 remaining, truly APC mutation-negative polyposis patients displayed a significantly later age at diagnosis compared with APC mutation carriers (46.1 versus 35.2 years; P < 0.01). APC mutation-negative individuals with >100 colonic polyps were more likely to present with extracolonic disease (P < 0.05) than those with <100. Assessment of microsatellite instability (MSI), a hallmark of mismatch repair deficiency, in 68 tumors from 21 truly APC mutation-negative patients, identified 4 (5.9%) unstable tubulo-villous adenomas (3 MSI-High and 1 MSI-Low), stemming from 4 (19%) unrelated individuals and likely to be caused by hMLH1 promoter hypermethylation. In conclusion, only a small proportion of APC germ-line mutation carriers is missed by the protein truncation test, and mismatch repair deficiency does not seem to substantially contribute to tumor development in APC mutation-negative polyposis patients.

3' Untranslated Regions↗
PubMed2001

[Relative bioavailability of diclofenac after a single administration of a new multiple-unit formulation of enteric-coated pellets].

The relative bioavailability of diclofenac (CAS 15307-86-5) was investigated after a single administration of a multiple-unit formulation containing 75 mg diclofenac sodium in enteric-coated pellets (A) in comparison to an enteric-coated tablet with 50 mg diclofenac sodium (B), a capsule containing 140 mg diclofenac resinate (C) and a dispersible tablet containing 46.5 mg diclofenac acid (D). The study was carried out in a four-way crossover design in 16 healthy male volunteers. Serum concentrations of diclofenac were determined with a validated and specific HPLC-method. After dose normalisation, a mean relative bioavailability of 99% (B), 142% (C) and 116% (D) was determined for the pellet formulation. According to the corresponding 90%-confidence interval, bioequivalence for the extent of bioavailability of the test formulation can be concluded compared to the enteric-coated tablet. In comparison to the formulations C and D, the test formulation showed an increased extent of bioavailability. Further differences in pharmacokinetics were observed for the rate-dependent parameters. For the test formulation, the highest mean maximum serum concentration (1595 ng/ml) was measured with a corresponding tmax of 0.8 h. For the reference formulations, mean peak serum concentrations of 1285 ng/ml after 2.0 h (B), 370 ng/ml after 1.8 h (C) and 735 ng/ml after 1.9 h (D) were observed. Despite the enteric-coating of the pellets, a short lagtime of 0.4 h was determined for the test formulation. For the other rapid-release formulation (D), the lagtime was of a similar magnitude (0.3 h), while drug release and absorption from the enteric-coated tablet and the diclofenac resinate capsule were delayed (1.8 and 0.7 h, respectively). Due to the rapid and high bioavailability of diclofenac, the multiple-unit formulation fulfills the prerequisites for the oral treatment of acute painful conditions when prompt analgesic and anti-inflammatory efficacy is desired.

Adult↗
PubMed2001

Left ventricular function in mice lacking the AT2 receptor.

OBJECTIVES: The role of the AT2 receptor in the heart is incompletely understood. We investigated left ventricular performance in AT2 receptor knockout mice, with and without deoxycorticosterone acetate (DOCA)-salt treatment. Given the putative opposing functions of the AT1 and AT2 receptor, we also analysed AT1 receptor expression in the left ventricle. METHODS: We used a miniaturized conductance-manometer system to measure pressure-volume loops for analysing left ventricular performance under baseline conditions and after increasing peripheral vascular resistance. We determined left ventricular AT1-receptor expression by RNase-protection assays. RESULTS: In AT2 receptor knockout mice, end-systolic and end-diastolic volumes were lower than in wild-type mice, so that pressure-volume loops were shifted leftward. Left ventricular systolic and diastolic kinetics were not different between the groups. AT2 receptor knockout mice and wild-type mice both stabilized their reduced stroke volume after laparatomy as peripheral resistance was increased. DOCA-salt treatment increased elastance in AT2 receptor knockout mice, compared to controls. Furthermore, AT2 receptor knockout mice had a steeper increase in dP/dtmax. Left ventricular AT1 receptor gene expression was increased in AT2 receptor knockout mice and was not down-regulated in response to DOCA-salt treatment. Finally, the hearts of AT2 receptor knockout mice were smaller than controls, but increased in size in response to DOCA-salt treatment. CONCLUSIONS: AT2 receptor knockout mice displayed no major changes in left ventricular function at baseline or in response to DOCA-salt treatment, compared to wild-type mice. The AT2 receptor may be important to AT1 receptor expression in response to DOCA-salt challenge and may have some influence on cardiac growth responses.

Animals↗
PubMed2000

Design of adenosine kinase inhibitors from the NMR-based screening of fragments.

A strategy is described for designing high-affinity ligands using information derived from the NMR-based screening of fragments. The method involves the fragmentation of an existing lead molecule, identification of suitable replacements for the fragments, and incorporation of the newly identified fragments into the original scaffold. Using this technique, novel substituents were rapidly identified and incorporated into lead inhibitors of adenosine kinase that exhibited potent in vitro and in vivo activities. This approach is a valuable strategy for modifying existing leads to improve their potency, bioavailability, or toxicity profile and thus represents a useful technique for lead optimization.

Adenosine Kinase↗
PubMed2000

On a new artificial mediator accepting NADP(H) oxidoreductase from Clostridium thermoaceticum.

The purification and partial characterisation of an NADP(H) dependent artificial mediator accepting pyridine nucleotide oxidoreductase (AMAPOR) from the anaerobic Clostridium thermoaceticum is described. Depending on the redox potential of the artificial mediators the AMAPOR is able to regenerate NADP+ or NADPH rendering the enzyme useful for preparative work applying NADP(H) dependent oxidoreductases. At 37 degrees C crude extracts of C. thermoaceticum have an AMAPOR activity of 5-7 U mg(-1). This is 28 degrees under the optimal growth temperature of this microrganism. Out of apparently more than 10 AMAPOR active proteins in the crude cell extracts visible after electrophoresis and activity staining on the gel, two of these proteins were isolated. They seem to be two different oligomers. According to gel electrophoresis they show apparent molecular masses of about 200 and 400 kDa. These two forms showed after SDS gel electrophoresis two monomers with apparent molecular masses of 42 and 56 kDa which we call alpha and beta. The two oligomers may have the compositions alpha2beta2 and alpha4beta4. They contain Fe/S cluster and FAD. Various amounts of the FAD were lost during the purification procedure. This loss is partially reversible after addition of FAD. The AMAPOR reacts with rather different artificial mediators such as viologens, quinones e.g. 1,4-benzoquinone or anthraquinone-2,6-disulphonate, 2,6-dichloro-indophenol and clostridial rubredoxin. Two different ferredoxins from C. thermoaceticum, oxygen or lipoamide are no substrates indicating the here described AMAPOR is not a diaphorase in the usual sense.

Amino Acid Sequence↗
PubMed2000

A palliative accelerated irradiation regimen for advanced non-small-cell lung cancer vs. conventionally fractionated 60 GY: results of a randomized equivalence study.

PURPOSE: Radiation oncologists are often faced with patients with advanced non-small-cell lung cancer (NSCLC), who are not suitable candidates for state-of-the-art radical treatment, but who also are not judged to have a very short life expectancy. Some physicians treat these patients palliatively, whereas others advocate more intensive treatment. To find out if there is a substantial difference in outcome between these approaches, we performed a randomized prospective study. METHODS AND MATERIALS: Between 1994 and 1998, 152 eligible patients with advanced NSCLC Stage III (n = 121) or minimal Stage IV (n = 31) were randomized to receive conventionally fractionated (cf; A: 60 Gy, 6 weeks, n = 79) or short-term treatment (PAIR; B: 32 Gy, 2 Gy b.i.d.; n = 73) of tumor and mediastinum. RESULTS: One-year survival rate for all patients was 37% with no significant difference between the two treatment arms (A: 36%; B: 38%; p = 0.76). As far as can be judged from limited data available, palliation was adequate and similar for the two treatment arms. Apart from expected differences in the time course of esophagitis, acute side effects were moderate and equally distributed. No severe late effects were observed. CONCLUSIONS: In the present randomized trial, survival and available data on palliation were not different after cf to 60 Gy compared to the palliative PAIR regimen. Therefore, for patients who are not suitable for radical treatment approaches, the prescription of a palliative short-term irradiation appears preferable compared to cf over several weeks.

Adenocarcinoma↗