The pleiotropic functions of peroxisome proliferator-activated receptor γ

Peroxisome proliferator-activated receptors (PPARs) are nuclear hormone receptors, initially described as molecular targets for synthetic compounds that induce peroxisome proliferation. PPARgamma is the best characterized of the PPARs. The heterodimer of PPARgamma with the retinoid X receptor (RXR) plays a crucial role in adipogenesis and insulin sensitization. The RXR/PPARgamma heterodimer furthermore has been reported to have important immunomodulatory activities and to affect cell proliferation/differentiation pathways in various malignancies. PPARgamma is activated by a number of naturally occurring fatty acid derivatives and by several synthetic compounds, including the thiazolidinediones and L-tyrosine-based insulin sensitizers. This review gives an overview of the pleiotropic functions of PPARgamma and discusses the wide-ranging medical implications that modulation of PPARgamma activity might have for various diseases, ranging from obesity and type 2 diabetes to cancer and inflammation.     

Ein vereinfachtes Spektrophotometer zur Bestimmung des Hämoglobin- und Sauerstoffgehaltes im Blut

Ohne ZusammenfassungMit 12 Textabbildungen     

Karyotypic evolution in Ph-positive chronic myeloid leukemia in relation to management and disease progression

In a prospective study of 32 patients with chronic myeloid leukemia the frequency of chromosome abnormalities in addition to the Philadelphia chromosome (Ph) increased when the disease progressed. Before metamorphosis, 10 patients (31%) had developed additional abnormalities. Such abnormalities were present in three of them at the time of diagnosis; in the other seven, they were detected late in the chronic phase. New clonal abnormalities heralded or accompanied a more malignant phase of the disorder, usually a blastic leukemia. During metamorphosis, 78% of the patients had additional abnormalities, which in 68% of these cases comprised at least one of +8, +22q- or i(17q). Clones with additional abnormalities disappeared in eight cases, either spontaneously or in association with cytostatic therapy during the chronic or blastic phase. Involvement of chromosome #8, usually in the form of a trisomy, was found in 7 of 12 patients treated with busulfan, but was not found in any of the 10 hydroxyurea-treated patients, of whom 8 were splenectomized early during the chronic phase. Cells from the spleen, obtained by fine needle aspiration or splenectomy were cytogenetically examined in 18 cases during the chronic phase, but abnormalities in addition to the Ph were noted in only one patient, who was examined in the late chronic phase. The same abnormalities were present in bone marrow cells of this patient.     

In vivo magnetic resonance imaging explorative study of ectopic bone formation in the rat

In animal studies of tissue engineering of bone, histology remains the standard for assessing bone formation. As longitudinal studies with this method are feasible only at the cost of large numbers of animals, we looked for an alternative. Therefore, demineralized bone matrix (DBM) and inactivated demineralized bone matrix (iDBM) implants were subcutaneously implanted in a rat. At 1, 3, 5, and 7 weeks postimplantation soft X-ray and magnetic resonance imaging (MRI) were done to monitor bone formation in the implants. At 7 weeks, the animal was killed and the implants were retrieved for histology. Our results showed that in vivo MRI is well suited to assess bone formation larger than 0.5 mm in diameter and to monitor the complete three-dimensional shape of the newly formed bone noninvasively and longitudinally. The MRI results matched well with the histology results obtained at 7 weeks. In contrast, X-ray imaging appeared inappropriate to monitor the bone formation process in DBM.     

13C NMR spectroscopic studies on polyanion-polycation complexes and their component polyelectrolytes

Position and intensities of the ¹³C NMR signals and relaxation times T₁ of several anionic and cationic polyelectrolytes in the solid state were compared with those of the appropriate polyanion-polycation complexes. At a high charge density of the components, the most significant changes of the parameters in question due to complex formation are observed for the C atoms adjacent to the charge centers, indicating a strong Coulombic interaction. At lower charge density, conformational changes of the polymer chains have also to be taken into consideration.     

Expression of putative virulence factors by clinical isolates of Klebsiella planticola

A total of 92 clinical isolates of Klebsiella planticola from man was examined with respect to the production of haemagglutinins and siderophores, serum resistance and distribution of capsular types. For comparison, a group of 207 clinical isolates of K. pneumoniae was also studied. The percentages of K. planticola strains able to express mannose-sensitive haemagglutination, indicating type 1 fimbriae (83%) and mannose-resistant and Klebsiella-like agglutination, indicating type 3 fimbriae (69%), as well as to produce the siderophores enterobactin (100%) and aerobactin (2.2%) were almost identical to those of the K. pneumoniae strains. Similarly, the proportion of serum-resistant strains (30%) was comparable to that of K. pneumoniae (25%). The capsule types most often detected in K. planticola were K14 (13%), K2 (9%) and K70 (9%). The incidence of K2, which is the predominant capsular type in K. pneumoniae, was similar in both species. These findings show that K. planticola, which is being detected with increasing frequency in clinical specimens from man, has the ability to express similar putative virulence factors to K. pneumoniae, suggesting that they may have similar pathogenicity.