Differences in the satellite association pattern in the human population.
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Adult↗
Biomedical subjects
A Hansson
Publications and source records attributed to A Hansson.
The influence of culture method on the satellite association pattern in human lymphocytes: macroculture versus microculture.
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Adolescent↗
Comparison of methods for immobilization to carboxymethyl dextran sensor surfaces by analysis of the specific activity of monoclonal antibodies.
The authors have recently described the development of a carboxymethyl dextran-based sensor surface for biospecific interaction analysis by surface plasmon resonance. Ligands are immobilized via primary amine groups after activation of the carboxymethyl groups on the sensor surface with a mixture of N-hydroxysuccinimide and N-ethyl-N'-(dimethylaminopropyl) carbodiimide. Methods have now been developed for efficient immobilization via thiol/disulfide exchange, aldehyde coupling and biotin-avidin coupling. The specific activity of monoclonal antibodies immobilized by the four different methods was investigated by altering the immobilization conditions, e.g., activation time, protein concentration, ionic strength and the degree of modification, etc. Investigations have also been made concerning possible differences in the specific activity for antibodies immobilized using optimized conditions with respect to the four different chemistries. These studies show that, with the flexible carboxymethyl dextran matrix used here, the immobilization methods give rise to only minor differences in specific activity. Thus, with this solid support, a 'site directed' immobilization strategy for monoclonal antibodies has no advantage. In general the specific activity for optimized systems was approximately 75% for the binding of beta 2 mu-globulin to an immobilized monoclonal antibody directed against beta 2 mu-globulin. Reduced specific activities of immobilized antibodies induced by variation of the coupling conditions could be attributed to the deterioration of the active site of the antibody.
Animals↗
EM single particle analysis of the ATP-dependent BchI complex of magnesium chelatase: an AAA+ hexamer.
BchI, belonging to the AAA+ -protein family, forms the enzyme magnesium chelatase together with BchD and BchH. This enzyme catalyses the insertion of Mg2+ into protoporphyrin IX upon ATP hydrolysis. Previous studies have indicated that BchI forms ATP-dependent complexes and it is a member of the AAA+ -protein family (ATPases associated with various cellular activities) and it was suggested based on structural homology that the BchI formed hexameric complexes. AAA+ -proteins are Mg2+ -dependent ATPases that normally form oligomeric ring complexes in the presence of ATP. Single particle analysis of fully formed ring complexes of BchI observed by negative staining EM indicate that the BchI has strong 6- and 2-fold rotational symmetries and a weaker 4-fold rotational symmetry which are reminiscent of DNA helicase. A 2D average of the fully formed BchI-ATP ring complex is presented here from images of the complex obtained from negative staining EM. Other complexes are also observed in the EM micrographs and the class averages of these are indicative of the fragility and dynamic nature of the BchI complex which has been reported and they are suggestive of partially circular complexes with six or less protomers per particle. The resolution of the average circular complex is estimated at approximately 30A and it is similar in shape and size to an atomic resolution hexameric model of BchI rendered at 30A.
Adenosine Triphosphatases↗
Inhibited proliferation of fibroblasts derived from chronic diabetic wounds and normal dermal fibroblasts treated with high glucose is associated with increased formation of l-lactate.
Diabetes is accompanied by delayed wound healing and insufficient granulation tissue formation, possibly because of a defect in fibroblast function. We have previously shown that fibroblasts derived from chronic diabetic foot ulcers have lower proliferation compared with those from uninjured skin. The aim of this study was to investigate possible mechanisms explaining the impaired fibroblast proliferation observed in fibroblasts from non-insulin-dependent diabetes mellitus chronic wounds and normal fibroblasts cultured in high glucose. Fibroblasts from two groups of patients were studied: nondiabetic patients with chronic venous stasis ulcers and non-insulin-dependent diabetes mellitus patients with chronic diabetic wounds. Biopsies from both uninjured skin and wounds were taken from the same patients to serve as sources of fibroblasts. A fluorometric method was used to determine DNA content, and a spectrophotometric lactate oxidase method was used for lactate level analysis. We found a dose-dependent inhibition of normal fibroblast proliferation when adding conditioned media from non-insulin-dependent diabetes mellitus wound fibroblasts. The conditioned medium, from these cells showed elevated l-lactate levels, 6.3 +/- 0.7 mmol/L, compared with media derived from nondiabetic, 2.1 +/- 0.3 mmol/L (p < 0.01), and diabetic uninjured skin fibroblasts, 3.5 +/- 0.6 mmol/L, and from chronic nondiabetic wound fibroblasts 2.9 +/- 0.3 mmol/L. Addition of 6 mmol/L l-lactate to uninjured normal fibroblasts resulted in decreased DNA content (58 +/- 7%, p < 0.01). Previously we have shown that high glucose concentrations inhibit fibroblast proliferation and induce growth factor resistance. When increasing the amount of d-glucose in the media, l-lactate levels increased in all cell types. When the uninjured normal cells were treated with beta-hydroxybutyrate, the total DNA content decreased by 42 +/- 5% (p < 0.05), with no significant increase in the l-lactate levels. These observations indicate that l-lactate production may be of importance for fibroblast proliferation in vitro and may play a role in fibroblast proliferation in vivo.
3-Hydroxybutyric Acid↗
Impaired proliferation and increased L-lactate production of dermal fibroblasts in the GK-rat, a spontaneous model of non-insulin dependent diabetes mellitus.
Intact fibroblast function is required for normal wound healing. Although healing is generally accepted to be disturbed in non-insulin dependent diabetes mellitus, the signals modulating this disturbance are not fully understood. Therefore, we studied dermal fibroblasts from the GK rat, a non-insulin dependent diabetes mellitus model, and the Wistar rat (control) regarding growth characteristics, and L-lactate production at 5.5 mM and 25.5 mM glucose in the absence or presence of protein kinase C-inhibition, or alpha-tocopherol acetate. In addition, growth and L-lactate responses to hyaluronic acid were assessed under normal glucose conditions. At 5.5 mM glucose, the fibroblasts from the GK rat showed a lower proliferation rate during the first 24 hours, measured as DNA content, as compared to Wistar rats, i.e. at 8 hours GK was 57% of control, p < 0.01, at 24 hours GK was 60% of control, p < 0.01. The GK rat fibroblasts accumulated higher L-lactate levels in the media at 24-96 hours. Addition of glucose at a concentration of 25.5 mM decreased the total DNA content in GK rat fibroblast cultures to 74% (p < 0.05) and in control to 87% (p < 0.05), and increased L-lactate levels, measured at 48 hours. A protein kinase C-inhibitor, bisindolylmaleimide IX, increased DNA content and decreased L-lactate in both cell types during culture in high glucose, but only affected GK rat fibroblasts during normal glucose. Hyaluronic acid, increased DNA content in both types of fibroblasts, GK: 139% (p < 0.05), control: 127% (p < 0.05) and reduced L-lactate production. The above observations indicate that GK rat fibroblast proliferation is suppressed when the cells are cultured in high glucose containing media. In addition, protein kinase C and hyaluronic acid might play a role as modulators of fibroblast proliferation during the diabetic state.
Adjuvants, Immunologic↗
Uniform expression of alcohol dehydrogenase 3 in epithelia regenerated with cultured normal, immortalised and malignant human oral keratinocytes.
The human oral epithelium is a target for damage from the inhalation of formaldehyde. However, most experimental studies on this chemical have relied on laboratory animals that are obligatory nose breathers, including rats and mice. Therefore, in vitro model systems that mimic the structure of the human oral epithelium and which retain normal tissue-specific metabolic competence are desirable. Based on the established role of alcohol dehydrogenase 3 (ADH3), also known as glutathione-dependent formaldehyde dehydrogenase, as the primary enzyme catalysing the detoxification of formaldehyde, the aim of this study was to investigate the expression of ADH3 in organotypic epithelia regenerated with normal (NOK), immortalised (SVpgC2a) and malignant (SqCC/Y1) human oral keratinocytes. Organotypic epithelia, usually consisting of 5-10 cell layers, were produced at the air-liquid interface of collagen gels containing human oral fibroblasts, after culture for 10 days in a standardised serum-free medium. Immunochemical staining demonstrated uniform expression of ADH3 in these organotypic epithelia, as well as in the epithelial cells of oral tissue. The specificity of the ADH3 antiserum was ascertained from the complete neutralisation of the immunochemical reaction with purified ADH3 protein. Assessment of the staining intensities indicated that the expression levels were similar among the regenerated epithelia. Furthermore, the regenerated epithelia showed similar ADH3 expression to the epithelium in oral tissue. Therefore, a tissue-like expression pattern for ADH3 can be generated from the culture of various oral keratinocyte lines in an organotypic state. Similar expression levels among the various cell lines indicate the preservation of ADH3 during malignant transformation, and therefore that NOK, SVpgC2a and SqCC/Y1 represent functional models for in vitro studies of formaldehyde metabolism in human oral mucosa.
Alcohol Dehydrogenase↗