Identification of a voltage- and calcium-dependent non-selective cation channel in cultured adult and fetal human nasal epithelial cells

The apical membranes of cultured human nasal epithelial cells from adults and fetuses were investigated with the patch-clamp technique. Amiloride-insensitive, calcium- and voltage-dependent, non-selective cation channels were found in 4% of the cell-attached, and 18% of the inside-out and outside-out patches (n=412). Multiple functional channels were present in more than 90% of these patches, with a mean of 3.9 channels per patch (n=55). The current-voltage relationship can be described by the Goldman equations and the single channel conductance was 20.1±0.3 pS (n=29) in adult and 20.7±0.4 pS (n=44) in fetal cells in symmetrical 150mM NaCl solutions. The channels were highly selective for cations: P_Na/P_Cl was 30 in adult and 45 in fetal experiments. They were equally permeable for K⁺ and Na⁺, somewhat less for Cs⁺, and impermeable for choline⁺ and tetraethylammonium⁺. The open probability was voltage dependent: it increased approximately 2-fold with 30mV depolarization in the potential range from −60mV to +60mV. The channels were activated by Ca²⁺ concentrations of about 10⁻⁴M at the cytoplasmic side, but were insensitive to extracellular Ca²⁺ and amiloride (10⁻⁴M). The non-selective cation channels found in apical membranes of cultured fetal nasal epithelial cells were not different from the adult ones.     

The genome of bacteriophage phiKMV,a T7-like virus infecting Pseudomonas aeruginosa

The complete DNA sequence of a new lytic T7-like bacteriophage phiKMV is presented. It is the first genome sequence of a member of the Podoviridae that infects Pseudomonas aeruginosa. The linear G + C-rich (62.3%) double-stranded DNA genome of 42,519 bp has direct terminal repeats of 414 bp and contains 48 open reading frames that are all transcribed from the same strand. Despite absence of homology at the DNA level, 11 of the 48 phiKMV-encoded putative proteins show sequence similarity to known T7-type phage proteins. Eighteen open reading frame products have been assigned, including an RNA polymerase, proteins involved in DNA replication, as well as structural, phage maturation, and lysis proteins. Surprisingly, the major capsid protein completely lacks sequence homology to any known protein. Also, the strong virulence toward many clinical P. aeruginosa isolates and a short replication time make phiKMV attractive for phage therapy or a potential source for antimicrobial proteins.     

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.     

Expression and localization of mutant p16 proteins in melanocytic lesions from familial melanoma patients

Little is known about the correlation between the loss of p16 expression and tumor progression in familial melanoma; no systematic study has been conducted on p16 expression in melanocytic tumors from patients carrying germline CDKN2A mutations. We analyzed 98 early primary lesions from familial patients, previously tested for germline CDKN2A status, by quantitative immunohistochemistry using 3 p16 antibodies. We found that p16 expression was inversely correlated with tumor progression and was significantly lower in melanomas, including in situ lesions, than in nevi. Of other features analyzed, tumor thickness showed the most significant correlation with p16 levels. Lesions from mutation-negative patients displayed combined nuclear and cytoplasmic staining. However, some mutation-positive lesions (ie, G101W, 113insR, M53I, R24P, and 33ins24), including benign nevi, showed nuclear mislocalization, confirming previous studies suggesting that subcellular distribution indicates functional impairment of p16.