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Biomedical subjects

R Kunze

Publications and source records attributed to R Kunze.

54 records · Page 3Linked to original sources
PubMed1989

The putative transposase of transposable element Ac from Zea mays L. interacts with subterminal sequences of Ac.

The Ac-specific ORFa protein, overexpressed in a baculovirus system, specifically binds to several subterminal fragments of Ac. The 11 bp long inverted repeats of the transposable element are not bound by the ORFa protein. Major ORFa protein-binding sites were delineated on 60 and 70 bp long sequence segments that lie 100 bp inside of the 5' Ac terminus and 40 bp inside of the 3' terminus respectively. Within all strongly bound fragments, and particularly in these 60 or 70 bp long segments, the hexamer motif AAACGG is repeated several times in direct or inverted orientation. The ORFa protein binds to synthetic concatemers of this motif, whereas the mutant motif AAAGGG is not complexed. Methylation of the cytosine residues in the AAACGG motif and/or its complementary strand has pronounced effects: whereas one of the two hemimethylated sequences has a higher affinity to the ORFa protein than both unmethylated and holomethylated DNAs, the other hemimethylated DNA is virtually not complexed at all. The native ORFa protein binding sites are more complex than the AAACGG sequence: certain Ac and Ds1 fragments devoid of AAACGG motifs (but containing several similar sequences) are weakly bound by the ORFa protein.

Base Sequence↗
PubMed1989

Regression of oral Kaposi's sarcoma in a case of AIDS on zidovudine (AZT).

A case with oral Kaposi's sarcoma (KS) is reported that regressed during therapy with Zidovudine (AZT) which was started 5 months after the first dermal and oral tumours were noted. After 6 months of treatment the absolute number of T-helper cells had increased from 54/microliters to 232/microliters and the ratio of T-helper to T-suppressor cells from 0.15 to 0.3. During the same time the lesions of KS on the gingiva, uvula and the body as well as the face disappeared. The lesion of KS on the hard palate regressed.

Acquired Immunodeficiency Syndrome↗
PubMed1988

The thermodynamic essence of the reversible inactivation of Na+/K+-transporting ATPase by various digitalis derivatives is relaxation of enzyme conformational energy.

This paper reports on the kinetic and thermodynamic parameters describing the interaction of selected digitalis derivatives with hog and guinea-pig cardiac (Na+ + K+)-ATPase (Na+/K+-transporting ATPase EC 3.6.1.37). 32 digitalis derivatives were characterized as to the values of the delta G0', delta G----not equal to, and delta G----not equal to quantities in their interaction with (Na+ + K+)-ATPase from hog cardiac muscle in the presence of ATP, Mg2+, Na+ and K+. Nine derivatives were additionally characterized as to the values of the delta H0', delta S0', delta H----not equal to, delta S----not equal to, delta H not equal to, and delta S not equal to quantities in their interaction with the hog enzyme promoted by ATP, Mg2+ and Na+ in the presence or absence of K+. The formation of the inhibitory complexes is in any case an endothermic, entropically driven process. The Gibbs energy barriers in the formation and dissociation of the complexes, delta G----not equal to and delta G----not equal to, are imposed by large, unfavourable delta H not equal to values. K+ decreases the delta G0' value by increasing the delta G----not equal to value more than the delta G----not equal to value. In comparison with hog (Na+ + K+)-ATPase, the interaction of three derivatives with guinea-pig cardiac enzyme in the presence of ATP, Mg2+, Na+ and K+ is characterized by lower delta G0' values caused by lower favourable delta S0' values, and is accompanied by lower delta G----not equal to values. The magnitude of the kinetic parameters and the characteristic of the thermodynamic quantities describing the interaction between various digitalis derivatives and (Na+ + K+)-ATPase, indicate the induction of substantial conformational changes in the enzyme protein. A large entropy gain in the enzyme protein, observed irrespective of enzyme origin and ligation, appears to be the common denominator of the inhibitory action of all digitalis derivatives studied, suggesting that the digitalis-elicited relaxation of high conformational energy (negentropy strain) of the enzyme protein is the thermodynamic essence of the reversible inactivation of (Na+ + K+)-ATPase.

Adenosine Triphosphate↗
PubMed1988

Overproduction of the protein encoded by the maize transposable element Ac in insect cells by a baculovirus vector.

The polypeptide encoded in the Activator (Ac) element of Zea mays L. has been expressed in Spodoptera frugiperda insect cells using plasmids which carry the strong polyhedrin promoter of the baculovirus Autographa californica nuclear polyhedrosis virus (AcNPV). Recombinant AcNPVs with the Ac-cDNA integrated and under the control of the viral polyhedrin promoter have been isolated and their genomes have been partly characterized as to the location of the foreign DNA insert. Upon infection of S. frugiperda cells with the recombinant AcNPV, maize Ac element specific messenger RNAs, as well as a newly synthesized polypeptide with an apparent molecular weight of about 116 kDa, have been detected in extracts of recombinant infected cells. This polypeptide is absent from extracts of wild-type infected cells expressing the polyhedrin polypeptide which can be recognized by the presence of nuclear inclusion bodies. Recombinant infected cells lack this protein. The Ac specific polypeptide is detected by antisera, which have been raised against fusion proteins containing Ac sequences synthesized in Escherichia coli, both in immunoprecipitation and in Western blotting experiments. The Ac specific protein is a nuclear phosphoprotein and represents about 1%-2% of the newly synthesized protein.

Animals↗
PubMed1988

Immunohistochemical detection of HIV structural proteins and distribution of T-lymphocytes and Langerhans cells in the oral mucosa of HIV infected patients.

Seventeen biopsies taken from oral mucosa of HIV infected patients were analysed for the distribution of CD4+/CD8+ T-lymphocytes and Langerhans cells. The results were evaluated statistically. An increase in the absolute number of CD4+ and CD8+ cells in HIV infected patients without clinical symptoms, ARC or AIDS was seen in the connective tissue stroma when compared with normal oral mucosa from sero-negative patients. However, the ratio between CD4+/CD8+ cells was decreased due to the disproportionate increase of CD8+ cells. These findings did not show statistical correlation with the clinical status of the infection. In contrast to the increase in absolute number of CD4+/CD8+ cells the number of Langerhans cells was unchanged when compared with the control group. Using four different monoclonal antibodies against virus structural proteins (2 X anti p24, gp41, gp120) two of 26 patients showed labelled cells in consecutive sections in the same connective tissue areas. It was assumed that latently infected mononuclear cells invaded the oral mucosa together with uninfected cells of the cellular immune system.

AIDS-Related Complex↗
PubMed1987

Transcription of transposable element Activator (Ac) of Zea mays L.

Transcripts of various sizes hybridize to the transposable element Ac of Zea mays in most maize lines. A 3.5-kb mRNA with an abundance of 1-3 x 10 of the poly(A) RNA, however, is found exclusively in those lines that carry an active Ac. Plants with two Ac elements contain slightly more 3.5-kb Ac transcript than those with only one Ac. Overlapping cDNA clones spanning most of the message have been isolated and sequenced. The 5'-end of the transcript was determined by Northern hybridization and S1 mapping. It starts at several sites over a distance of nearly 100 bases, contains an AUG-free leader 600-700 nucleotides long, has a long open reading frame encoding 807 amino acids and an untranslated 3'-sequence of 239 nucleotides. Four introns with a combined length of 654 bases are removed from the primary transcript. Radiosequencing of in vitro translation products shows that translation of the long open reading frame begins at the first AUG, even though it is located in an unfavourable sequence context. The transcript is found in all organs investigated, provided an active Ac is present in the stock.

Journal Article↗
PubMed1987

[T lymphocyte subpopulations in anti-HIV-negative drug-dependent patients with intravenous abuse].

In the group of patients studied by us, we found a slight disturbance of the balance between immunoregulatory T helper/inductor lymphocytes and cytotoxic T suppressor lymphocytes which is usually characterised by a 2 to 1 ratio. This disturbance was due to the presence of an absolutely and relatively enhanced quantity of T suppressor cells, by which the relation of these T-cell subsets to each other was slightly lower than in the normal controls. The average ratio was 1.37 and was pathologically reduced in 19% of the patients. Activation and increase in the number of T suppressor cells in conjunction with a relative lymphocytosis are probably less due to a directly drug-induced effect than to an adequate immunoreaction to increased antigen stimuli such as infections with hepatitis B virus, viruses of the herpes group and other viral pathogens.

Adult↗
PubMed1983

AIDS in West Germany.

Explore the source record for details and available documents.

Acquired Immunodeficiency Syndrome↗
PubMed1977

[Comparative studies on the setting time of various phosphate cements and on the effect of differentiated powder-fluid ratios and air humidity on the setting time].

A comparative experimental study served to determine the standard consistency and setting time of various phosphate cements (according to DIN 13903). One of the products under investigation did not comply with standard specifications; therefore, from the viewpoint of setting behaviour, it cannot be recommended for cementing fixed tooth-restorations. It was shown that variations in the powder-liquid ratio affected the setting time, whereas variations in air humidity in the range from 50 to 100% exerted no signficant effects, which might lead to a simplication of material testing and quality control.

Humidity↗
PubMedDate not supplied

Defective monocyte to macrophage maturation in human immunodeficiency virus infection.

To look for possible defects in cells of the monocyte/macrophage system, blood monocytes from patients infected with human immunodeficiency virus (HIV) were cultured on hydrophobic Teflon for 7 days and their ability to differentiate into mature macrophages in the presence of serum was followed. The following parameters were studied as indicative of successful terminal maturation: (1) the expression of maturation-associated antigens (transferrin receptor, surface transferrin, the BA-2 antigen, MAX antigens), (2) the disappearance of the MOP15 antigen, and (3) a more than 20-fold increase in intracellular ferritin concentration. It was found that the patients' blood monocytes did not differentiate in vitro but rather remained immature precursor cells. If the same holds true in vivo, the results could indicate that the pathophysiology of the acquired immunodeficiency syndrome (AIDS) may be, to a large extent, linked with the functional consequences of this impaired monocyte-to-macrophage maturation.

AIDS-Related Complex↗
PubMedDate not supplied

MHC-antigens: constituents of the envelopes of human and simian immunodeficiency viruses.

Immunoelectron microscopy was applied to study the antigenic make-up of human and simian immunodeficiency viruses (HIV, SIV) grown in cells expressing either MHC class I (Molt-3) or MHC class I and II (H9) antigens. A variety of antibodies directed against the surface glycoprotein gp120 of HIV and against MHC class I and II antigens were employed. Consistent with earlier observations on the loss of HIV envelope components, gp120 was only weakly demonstrable on the mature virion. MHC class I determinants were present regularly in small amounts on HIV and SIV. Class II antigens, e.g. HLA-DR were found in high density on HIV and SIV grown in H9 cells, but were absent, as expected, on virus grown in Molt-3 cells. These cellular surface antigens are constituents of the virion. The presence of MHC class II antigens in virus preparations used for diagnostic purposes might explain some of the false positive results in HIV serology. Possible biological implications of these virus associated cellular antigens for the pathogenicity of HIV are discussed.

Animals↗