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Biomedical subjects

K Ulrich

Publications and source records attributed to K Ulrich.

At least 55 records · Page 3Linked to original sources
PubMed1985

Antibodies against HTLV-III in Danish haemophiliacs: relation to source of factor VIII used in treatment and immunological parameters.

18 out of 40 healthy Danish type A haemophiliacs had antibodies against HTLV-III as measured by an enzyme linked immunosorbent assay (ELISA). The overall seropositivity was 45%. A significant positive correlation was found between seropositivity and total lifetime dose of factor VIII and the age of the patients. 63% and 79% of the patients predominantly treated with commercial American and European preparations, respectively, had antibodies, compared with 11% among patients predominantly treated with Danish cryoprecipitate. Patients exclusively treated with preparations from a single source in the year prior to investigation showed 69% seropositivity when treated with American and European preparations. None of the patients treated with Danish cryoprecipitates prepared from voluntary Danish donors had antibodies. No difference between seropositive and seronegative groups was found in total lymphocyte count, leu 2+ cells, leu 3+ cells and leu 2+/leu 3+ ratio but the seropositive group had significantly higher total IgG and lower skin test score. It is concluded that treatment with local European preparation carries less risk of HTLV-III infection compared with commercial preparations from either the USA or Europe. The results also suggested that T-cell subset alterations among haemophiliacs are not primarily due to HTLV-III infection.

Antibodies, Viral↗
PubMed1985

Spontaneous expression of C-type virus in DBA/2 mice is associated with an increased rate of mortality, independent of neoplastic disease.

Ecotropic C-type retroviruses isolated from both normal and dimethylbenzanthracene-treated DBA/2 mice could be classified into three major groups, Ea, Eb, and Ec, that differed in structure and biology. Weanling DBA/2 mice were generally free of viruses, but a fraction of adult individuals became virus positive and were apparently selectively associated with a high expression of the Eb viruses. Some of the ecotropic viruses from DBA/2 mice acted as exogenous pathogens. They caused viremia and a moderate incidence of leukemia when injected into C3H and ST/a mice. In addition, they caused an appreciable number of early deaths without signs of malignancy. To evaluate the natural role of the viruses, we studied the survival of spontaneously viremic and nonviremic DBA/2 mice. The viremic animals as a group were characterized by a significantly reduced life-span that was not related to neoplasia. These observations indicated that endogenous C-type retroviruses can be pathogenic without preselection of the host for disease. They also emphasize that endogenous viruses, like their exogenous counterparts, can have a broader pathogenic spectrum than normally appreciated.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1983

Variants of type-C retroviruses from DBA/2 mice: protein-structural and biological properties.

Ecotropic murine leukemia viruses isolated from normal and carcinogen-treated DBA/2 mice can be classified into three main groups that differ in structure and biology. Two groups, called Ea and Eb, consist of N-tropic viruses related to the standard endogenous ecotropic virus of AKR mice. Ea viruses replicate with reduced efficiency in cell lines derived from C3H mice, while Eb viruses essentially replicate normally in these cells. As elsewhere reported, Ea viruses appear apathogenic in C3H mice, while Eb viruses cause a moderate incidence of late leukemias. The biological differences are associated with modulations of the fine structure of the gag gene-encoded proteins. A third group of viruses, called Ec, is clearly more diverged. They differ extensively from Ea and Eb viruses in the products of the gag and env gene, and are related to Rauscher leukemia virus. Ec viruses are NB-ecotropic; they replicate efficiently in all mouse cells tested, and induce leukemias in C3H mice with shorter latency periods than Eb viruses. Since published nucleic acid hybridization data indicate that DBA/2 mice only carry one ecotropic provirus, we assume that the DBA/2 viruses represent a developmental series of variants evolving during the life of the animals.

Animals↗
PubMed1983

Antigenic modifications associated with 'spontaneous' malignant alterations of mouse fibroblasts propagated in vitro.

Two types of 'spontaneous' malignant alteration in vitro of ST/a mouse lung fibroblasts (ST-L) have been observed. In contrast to cells which retained their fibroblastic appearance (R- ST-L cells), cells showing morphological signs of transformation (R+ ST-L cells) developed strong isoimmunizing properties. Both types of cells expressed MuLV antigens which were found to be responsible for serum as well as cell-mediated immune reactions in vitro. The higher concentration of gp70 in R+ ST-L cells as compared to R- cells and possibly also the morphological differences in surface structure between the two cell types may account for the differences in immunogenicity. Preimmunization with R+ ST-L cells protected ST/a mice against secondary challenge with two ascites tumors (STABAL leukemia and Ehrlich). R- ST-L cells did not have a similar protective effect. However, the two ascites tumors only showed weak or no cross-reactions in vitro with sera and lymphoid cells from ST/a mice sensitized to R+ ST-L cells, and the in vitro reaction between the latter cells and sera or lymphoid cells from mice immunized against the two ascites tumors was moderate. This discrepancy between in vivo and in vitro observations is discussed.

Animals↗
PubMed1979

Serological identification of neoantigens on mouse fibroblasts which have undergone "spontaneous" malignant alteration in vitro.

ST-L1 is a cell line established from lung explants from a normal ST/a mouse. The ST-L1 cells have undergone spontaneous malignant alteration in vitro. The cells were rejected after inoculation into syngeneic immunocompetent hosts, and a syngeneic humoral immuneresponse against the ST-L1 cells has been detected. The specificity of this humoral response was investigated. The syngeneic response to ST-L1 was characterized by indirect immunofluorescence tests and by immunoprecipitation of radiolabelled cells and of a C-type virus produced by the cell lines. The specific anti-ST-L1 reactivities were found to be directed against the envelope glycoprotein of an endogenous C-type virus expressed by the antigenic cell line.

Animals↗
PubMed1978

Activation of C-type virus during chemically induced leukemogenesis in mice.

Repeated percutaneous applications of 7,12-dimethylbenz(a)anthracene on weaning DBA/2 and ST/a mice induced 100% leukemias with short latency periods. Endogenous C-type viruses were activated during the treatment as evidenced by (a) increased expression of the murine leukemia virus major core protein, p30, in blood and spleens and (b) increased frequency of detection of ecotropic virus by cocultivation of the splenocytes with SC-1 cells. The treatment did not affect p30 expression in several nonlymphoid organs, and detection of xenotropic viruses in the splenocytes was decreased. Virus expression did not correlate with the progression of disease in that (a) high p30 levels were generally found in mice with relatively low spleen weights and (b) p30 levels had no obvious connection to survival of the individual. 7,12-Dimethylbenz(a)anthracene treatment had little influence on p30 expression in spleens and blood from C3H and BALB/c mice, which are less sensitive to 7,12-dimethylbenz(a)anthracene-induced leukemogenesis. The results indicate an association of C-type virus activation with chemical induction of leukemia but do not necessarily imply an etiological role of the virus in the disease.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1977

Treatment of Mycoplasma hyorrhinis contaminated tissue cultures with a mixture of antibiotics.

Results obtained using a combination of antibiotics to control mycoplasmas in tissue cultures are described. Cell strains and established cell lines from several mammalian species grown in tissue culture were found to be highly contaminated with M. hyorrhinis. Cultures were treated with a mixture of three antibiotics consisting of gentamicin, tetracycline and chloramphenicol, and since that time tests for mycoplasmas in the treated cultures have consistenly yielded negative results. Apart from a transient cytostatic effect on the cells during the treatment, no apparent unwanted effects were observed. The mixture of three antibiotics appeared to be superior to treatment with antibiotics singly or combinations of two antibiotics.

Animals↗
PubMed1976

[Therapeutic problems in the infraposition of deciduous molars and molars].

Reflections on the nomenclature, aetiology and genesis are followed by seven case reports. Apart from the description of a new aspect of genesis and apart from therapeutical discussions of the single case, the authors draw some conclusions. The infraposition of deciduous molars requires orthodontic therapy, whereas that of permanent molars necessitates treatment at a special clinic. Suggestions for desirable further studies mark the end of the paper.

Adolescent↗