Anisotropy in nucleation and growth of two-dimensional islands during homoepitaxy on "hex" reconstructed Au(100).
Explore the source record for details and available documents.
Journal Article↗
Biomedical subjects
S Günther
Publications and source records attributed to S Günther.
Infection of human polyomaviruses JC and BK in peripheral blood leukocytes from immunocompetent individuals.
Widely disseminated infection with the human polyomaviruses JC and BK is followed by lifelong asymptomatic viral persistence that can be reactivated under prolonged immunosuppression to fatal CNS and urogenital disease. In an attempt to understand the pathogenesis of polyomavirus diseases, we asked whether leukocytes are involved in polyomavirus infection in the immunocompetent host. Peripheral blood leukocytes from 29 immunocompetent individuals and umbilical cord blood from 10 newborn children were analyzed for the presence of polyomavirus DNA. Southern blot analysis demonstrated the presence of JCV-specific full-length virus genomes and indicated involvement of the second human polyomavirus BK. In contrast to specimens from newborn children, PCR amplification of target DNA in the adult age group followed by species-specific hybridization provided evidence of concomitant JCV and BKV infection in almost all specimens. Nucleotide sequencing of virus-specific products representing DNA segments essential for virus multiplication confirmed presence of both virus species in leukocytes. The detection of a new virus subtype and single base changes or deletions in the noncoding DNA region from individual cases suggested widespread heterogeneity in the circulating virus population, although the structure of the transcriptional control elements in all cases was comparable to highly active elements found in lytically infected cells. Those findings and the localization of both virus types in the nuclei of blood cells by in situ hybridization demonstrate that JCV and BKV frequently infect peripheral leukocytes and give strong evidence that leukocytes are common sites of polyomavirus persistence in healthy individuals.
BK Virus↗
Calculation of subsite affinities of human small intestinal glucoamylase-maltase.
Several years ago, Hiromi et al. (1973) Biochim. Biophys. Acta 302, 362-375 proposed a theory for the action patterns of glucoamylases, based on data from steady-state kinetics. The Michaelis-Menten constants (Km) and the turnover number for maltooligosaccharides were used to evaluate the subsite affinities. We have now used this method for evaluating the subsite affinities for glucoamylases(EC 3.2.1.3)-maltase (EC 3.2.1.20) from human intestinal mucosa. For calculation of the subsite affinities, A1 and A2, and the intrinsic rate constant kint, we use a modified algorithm and a computer program for nonlinear least square fitting. Considerable substrate inhibition was shown by maltotriose, minor inhibition by maltotetraose, and no inhibition by maltose and the other maltooligosaccharides. This indicates a more complex kinetic behaviour of the enzyme with respect to maltotriose. Evaluation of the subsites reveals that A2 is the main binding site (18.1 kJ/mol), whereas the other affinities, with the exception of A1, are lower than 2.5 kJ/mol.
Glucan 1,4-alpha-Glucosidase↗
Heterogeneity of hepatitis B virus C-gene sequences: implications for amplification and sequencing.
Occasionally direct sequencing of amplified hepatitis B virus DNA leads to weak signals on autoradiograms. Using amplified C-gene sequences we investigated whether this is due to sequence heterogeneity of virus populations and use of inappropriate primers for direct sequencing. High C-gene sequence heterogeneity (point mutations, stop codons and a one codon deletion) was observed in HBV genomes from serum of a chronic carrier who underwent interferon treatment. The type of C-gene mutations detected by direct sequencing depended on the type of primers used. Cloning and sequencing of amplified C-gene sequences demonstrated that this was due to mutations in the region complementary to the sequencing primer. These data demonstrate the existence of novel HBV C-gene mutants and imply that multiple or degenerate sequencing and amplification primers are essential for accurate evaluation of the extent of HBV C-gene heterogeneity. Based on comparative sequence analysis of all available completely or incompletely sequenced C-genes, guidelines for optimal primer design are proposed for similar studies.
Adult↗
Complete heart block in a 9 year old girl caused by borreliosis.
A complete atrioventricular block was seen in a nine year old girl in whom an infection with Borrelia burgdorferi was confirmed by serological testing. There were no other symptoms or cutaneous manifestations of the disease. Though a rash on the right ear was later recalled by her parents. The patient was treated with high dose penicillin and orciprenaline was given intermittently. The complete heart block disappeared within four days.
Child↗
Frequent and rapid emergence of mutated pre-C sequences in HBV from e-antigen positive carriers who seroconvert to anti-HBe during interferon treatment.
Hepatitis B virus (HBV) variants which cannot express e-antigen (HBeAg) are characteristic for many viremic anti-HBe positive chronic carriers who often have particularly severe and fluctuating hepatitis. Whether such variants are selected for and are less amenable to interferon treatment is under dispute. Therefore, by DNA amplification and direct sequencing we have investigated the emergence of HBV pre-C sequence variants in nine e-antigen positive chronic carriers, all of whom seroconverted to anti-HBe or lost HBeAg during interferon treatment, and in three of whom no viral DNA was detectable after interferon treatment. In most, but not all of the patients we found newly emerging pre-C sequences in a subpopulation of the viral genomes that included silent point mutations, amino acid changes, start and stop codon and frameshift mutations. The emergence of these mutations was paralleled by a drastic decrease of viremia during treatment. The observed mutations appeared most frequently during interferon treatment. Some of the mutations appeared or disappeared late after interferon treatment concomitant with anti-HBe antibody development. The appearance or lack of mutations in the pre-C region of a subpopulation of HBV of these patients was independent of successful virus elimination. These data indicate that interferon treatment is frequently associated with the simultaneous fall in titer of viral DNA by several orders of magnitude and the emergence of novel pre-C sequences, some of them preventing HBeAg expression. However, the presumably immune-mediated selection for pre-C mutant viruses and decrease in viremia under interferon treatment appears not to be prognostic for successful or unsuccessful virus elimination.
Adult↗
Serum proteins of rats exposed to organic solvents examined by horizontal two-dimensional electrophoresis with an immobilized pH gradient in the first dimension.
Serum proteins of rats, exposed to methoxyethylacetate and a combination of methoxyethylacetate and isobutylacetate, were analyzed by horizontal high resolution two-dimensional gel electrophoresis with immobilized pH gradients in the first dimension. A total of 410 polypeptides were detected with either increasing or decreasing spot intensities after rat exposure to the organic solvents.
Acetates↗
The effects of theophylline on beta 2-adrenoceptors on polymorphonuclear leukocytes of asthmatic children and juveniles. Increase in receptor density and prevention of agonist-induced down-regulation.
The density (Bmax) and affinity (KD) of beta 2-adrenoceptors in polymorphonuclear leukocytes (PMN) were measured in 29 children and juveniles with mild or moderate asthma and in 25 healthy control subjects using the highly specific radioligand (+/-)-125I-cyanopindolol. No significant difference in Bmax was found between asthmatic subjects without medication and the control group. The asthmatic subjects were divided into four different groups by their actual medication: no medication, adrenergics, theophylline, adrenergics plus theophylline. Analysis of variance revealed highly significant differences between these groups for Bmax (P = 0.0016) but not for KD. In asthmatics on adrenergic therapy Bmax was significantly lower (995 +/- 415) than in asthmatics without medication (1660 +/- 521; P = 0.008). In contrast, Bmax in asthmatics on theophylline therapy was significantly higher (2137 +/- 231; P = 0.009) than in the controls. Bmax was average in the group of asthmatics treated with both adrenergics and theophylline (1619 +/- 547). It is concluded that in asthmatic subjects therapy with theophylline increases the density of beta 2-adrenoceptors and partly prevents their down-regulation induced by adrenergic therapy.
Adolescent↗
Analysis of porcine erythrocyte lysate proteins by horizontal two-dimensional electrophoresis with immobilized pH gradient in the first dimension.
Horizontal two-dimensional gel electrophoresis with immobilized pH gradients in the first dimension resulted in excellent patterns of porcine erythrocyte lysate proteins. The overwhelming excess of hemoglobin was removed by chloroform-ethanol extraction and the number of spots further increased by acetone precipitation, revealing considerably more protein spots than detected by analyzing the untreated sample. A total of 430 protein spots have been reproducibly obtained for further analysis of genetic variations. A number of enzyme systems have been identified by visual inspection and comparison with previous results. The existence of further multiple forms for other enzymes is also apparent.
Animals↗
[Hospital public health inspections in clinico-chemical laboratories of the Potsdam district].
Under supervision of the County Hygiene Inspection the District Hygiene Inspection made in 1987 in 88 clinical-chemical laboratories inspections acc. to hospital-hygienic criteria. With the exception of 13 institutions, all the other laboratories checked-up showed in part essential deficiencies with their regimens of disinfection and sterilization. These deficiencies could be removed immediately in most of the cases.
Disinfection↗
[Hospital public health status in community health nursing units of the Potsdam district].
By the instruction of the country hygiene inspection 452 community health nurse departments were inspected with special regard to hospital hygiene by the district hygiene inspections in the district of Potsdam. In addition to insufficiencies concerning the situation from the point of view of communal hygiene mistakes concerning the disinfection- and sterilization-regime of the community health nurses were observed frequently. By the check-ups and instructions the situation could be improved.
Community Health Nursing↗
Approach to stationary two-dimensional pattern: influence of focusing time and immobiline/carrier ampholytes concentrations.
Horizontal two-dimensional (2-D) electrophoresis with immobilized pH gradients (IPG) in the first dimension for buffer soluble proteins and for complex proteins solubilized in the presence of Nonidet P-40 (Görg et al., Electrophoresis 1987, 8, 45-51), has been extended to analyze basic proteins of yeast cells focused under non-equilibrium and equilibrium conditions. Transient state isoelectric focusing (IEF) in IPG gels revealed sample smearing and background staining, displaying horizontal streaks in the resultant 2-D patterns. Inclusion of 0.5% carrier ampholytes (CA) to the IPG gel (IPG-CA), resulted in the formation of many sharp protein bands after transient state IEF with resultant distinct spots in the 2-D patterns; however, resolution was poor and the gel contained heavy background staining. With prolonged focusing time, background staining disappeared and there was less difference in the final steady state IEF patterns obtained with IPG and IPG-CA. Reduction of the Immobiline concentration to one third the manufacturer's recommended amount did not improve IEF resolution with respect to streaking and background staining under either transient state or equilibrium conditions. In general, spot intensities were less on 2-D gels using diluted IPG gels than with "standard" IPG gels. Optimization of 2-D electrophoresis with IPGs in the first dimension was strongly related to IEF conditions. The use of IPG gels focused to equilibrium should not only improve inter-gel reproducibility and resolution but also the quality of the final 2-D patterns with respect to background staining and horizontal streaking.
Ampholyte Mixtures↗
Horizontal two-dimensional electrophoresis with immobilized pH gradients using PhastSystem.
Protocols for horizontal two-dimensional electrophoresis with immobilized pH gradients in the first dimension were modified for horizontal micro two-dimensional electrophoresis using PhastSystem. Different equilibration conditions of the first-dimensional immobilized pH gradient gel strip prior to second-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis were evaluated. Silver stained two-dimensional patterns were obtained within 3.5 h.
Electrophoresis, Gel, Two-Dimensional↗
The current state of two-dimensional electrophoresis with immobilized pH gradients.
Explore the source record for details and available documents.
Electrophoresis, Gel, Two-Dimensional↗
Dual-label autoradiographic analysis of human skin fibroblast and myoblast proteins by two-dimensional polyacrylamide gel electrophoresis using immobilised pH gradients in the first dimension.
Horizontal two-dimensional polyacrylamide gel electrophoresis with immobilised pH gradients in the first dimension has been applied to the analysis of human skin fibroblast and muscle myoblast total cell proteins. Excellent two-dimensional separations of skin fibroblast proteins were obtained using pH 4-10 immobilised pH gradient gels with a long interelectrode distance (16 cm), but resolution was degraded, particularly of the more acidic proteins, by the use of shorter (10 cm) gels. Improved resolution of acidic and basic proteins was obtained using separate pH 4-7 and pH 7-10 immobilised pH gradient gels respectively in the first dimension. Two-dimensional protein maps of skin fibroblast proteins were visualised both by silver staining and by autoradiography of samples labelled synthetically with [35S]methionine. Horizontal two-dimensional electrophoresis, using pH 4-7 and pH 7-10 immobilised pH gradient gels in the first dimension, was applied to the analysis of protein samples from skin fibroblasts and muscle myoblasts dual-labelled synthetically with [35S]methionine and [75Se]selenomethionine in an attempt to identify sets of proteins specific to each cell type. In addition, two-dimensional maps or protein samples derived from normal individuals and patients with Duchenne muscular dystrophy were compared to search for protein changes associated with the disease state. Although sets of qualitative protein spot differences were observed by visual inspection of the two-dimensional gels, more rigorous qualitative and quantitative analysis of the patterns using a computerised analysis system will be required to obtain the maximum amount of information from these data.
Autoradiography↗
Acid phosphatase typing for breeding nematode-resistant tomatoes by isoelectric focusing with an ultranarrow immobilized pH gradient.
The genetic variants of tomato acid phosphatase (Aps-1) systems have been analyzed by isoelectric focusing in immobilized pH gradients (IPG). By using an ultranarrow pH 4.25-4.55 IPG gel, the two genotypes Aps-1(1) and Aps-1+, differentiating tomato variants into nematode-resistant or nematode-susceptible plants, are separated into two sharp zones over a distance of 2.5 cm with isoelectric points of 4.37 and 4.43, respectively. Under these conditions, silver staining of the Aps-1 variants proved to be superior to enzyme staining. By applying more than 50 samples on one IPG gel, this method proved to be a powerful tool for reliable tomato nematode resistance screening.
Acid Phosphatase↗
Two-dimensional electrophoresis of plant proteins.
Explore the source record for details and available documents.
Electrophoresis, Gel, Two-Dimensional↗
[Results of controls of hospital health in physical therapy facilities of the Potsdam district].
Explore the source record for details and available documents.
Cross Infection↗