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Biomedical subjects

B Arnold

Publications and source records attributed to B Arnold.

At least 109 records · Page 6Linked to original sources
PubMed1984

Cytolytic T cells recognize the two amino-terminal domains of H-2 K antigens in tandem in influenza A infected cells.

We have genetically engineered three alleles of the K locus of the major histocompatibility complex (MHC) of the mouse. These novel hybrid H-2K genes were introduced into mouse 1T 22-6 cells (H-2q), and their products were shown to be expressed on the cell surface. The hybrid H-2 K antigens were examined for their ability to function as restricting elements for cytotoxic T lymphocytes during influenza A infection. Both the alpha 1 and alpha 2 domains of the Kd antigen were required for T cell recognition. This implies an important role for "conformational determinants" on H-2 antigens acting as restricting elements. The cytoplasmic domain of the Kb antigen is not phenotypically important for recognition by T cells.

Amino Acid Sequence↗
PubMed1984

Comparative morphology of cells located on glass and in the loose connective tissue: a study by scanning electron microscopy.

Most of the studies dealing with cellular shape, surface configuration, and motility are carried out in vitro on plane substrata. During the past years, the direct transfer of results obtained under these conditions to the cellular behavior displayed in the living organism, has been increasingly challenged. For this reason we have investigated the above mentioned functions of different cell classes localized on glass and in the loose connective tissue. The cells utilized were: fibroblasts and macrophages from normal rat and rabbit mesenteries, V2 rabbit carcinoma cells and L5222 rat leukemia cells. The combination of time-lapse cinematography and scanning electron microscopy revealed that motility and surface features are the same, irrespective of the immediate surrounding. Cellular shape and attachment, on the other hand, are dependent on the substrate. Fibroblasts, macrophages and cells of epithelial origin, including carcinoma cells, flatten on glass, but have a rounded configuration in the tissue. The flat leading lamellae displayed during locomotion on glass, are not evident in cells migrating through tissues. What regards attachment devices, extensively studied on glass, their formation and position within a tissue are, at present, a matter of speculation. Although it can be assumed that a similar process is operable in vivo and in vitro, clarification rests upon the use of ultrahistochemical techniques.

Animals↗
PubMed1984

Wage and hour laws. Their impact on 12-hour scheduling.

An often-overlooked aspect of implementing flexible scheduling is the existing payroll system and wage and hour laws. In this article, the authors of a 12-hour scheduling system discuss how they influenced the legislative process to help ensure the cost-effectiveness of their system.

Cost-Benefit Analysis↗
PubMed1984

Brain death.

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Brain Death↗
PubMed1983

Structural comparison of I-A antigens produced by a cloned murine T suppressor cell line with B-cell-derived I-A.

A cloned, antigen-specific T suppressor cell line derived from a CBA mouse expresses large amounts of I-A and I-E antigens. Comparative two-dimensional polyacrylamid gel electrophoresis of biosynthetically labeled I-A antigens immunoprecipitated with a variety of monoclonal I-Ak-specific antibodies suggested that alpha, beta and Ii polypeptide chains are identical with B-cell-derived I-A. Dimeric complexes formed by I-A chains derived from B or T suppressor cells were also similar with two major exceptions. Pulse-labeled T-cell-derived Ia antigen was complexed with two additional unknown components of about 31K. These components were not visible in pulse-chased (processed) materials. In addition, T suppressor-cell-derived I-A antigens did not contain S-S linked dimers consisting of processed alpha and beta chains, which are usually formed during solubilization of B cells. We consider the possibility that in T cells these chains are associated with other structures, thus preventing S-S linkage between alpha and beta chains.

Animals↗
PubMed1983

Cellular motility on glass and in tissues: similarities and dissimilarities.

Four neoplastic cell populations, two leukaemias and two carcinomas, were compared with regard to their motile behaviour on glass, on the surface of, and within the mesentery. This natural membrane was chosen because cells with invasive capacities can penetrate into its loose connective tissue where their movements were recorded by time lapse cinematography. Scanning electron microscopy was utilized to better visualize shape and surface specializations of cells moving in the three localizations. Analysis of time lapse films have shown that two populations, the L5222 rat leukaemia and the V2 carcinoma of the rabbit, contain cells with translocative motility. The non-locomotive cells of these populations and all cells of the other two populations (the BNML rat leukaemia and the human tongue carcinoma cell line LICR-HN1) exhibited stationary (non-translocative) motility. These basic patterns of cell motility remained the same irrespective of the environment. Regarding the influence of the structured elements of the loose connective tissue on overall shape and surface features, it was found that cells from the two leukaemias were the least affected. While BNML cells displayed their non-locomotive activity in a spherical configuration, the translocative L5222 cells migrated in the same shape as on glass. The anterior cytoplasmic extensions, however, were smaller and less variable. The two carcinoma cell populations were more influenced in both shape and cytoplasmic extensions. The well-spread configuration assumed by the stationary LICR-HN1 cells on glass was not maintained in the tissue. There the cells were more spherical. V2 carcinoma cells locomoting within the mesentery showed an increased ability to adapt their shape to the structured environment. The large leading lamellae, characteristic for V2 cells moving on glass, were not evident in the mesentery. They were replaced by smaller and longer cytoplasmic extensions. These observations indicate that the display of cellular locomotion as such does not depend on the environment. The latter, however, can induce adaptations of the cells' locomotive machinery which are expressed as modifications of overall shape and surface features.

Animals↗
PubMed1983

Some characteristics of mouse immune (y) interferon produced by a T-lymphoma cell line.

Mouse immune interferon was produced from a T-lymphoma cell line, L12-R4, upon stimulation with phorbol myristic acetate at a concentration of 2 x 10(-7) M/ml. The crude interferon, concentrated by precipitation with (NH4)2SO4 at concentration of 80%, was sequentially chromatographed on two sorbents, namely Sephacryl S-200 and Phenyl-Sepharose CL-4B. With molecular sieve chromatography L12-R4 interferon was observed to have an apparent molecular weight of 45.000 d, while from its chromatographic behaviour on Phenyl-Sepharose CL-4B interferon appeared to be highly hydrophobic like other mammalian interferons. The L12-R4 tumor cells therefore provide a unique source of immune interferon for purification and may represent an useful model for studying the molecular mechanisms involved in T cell differentiation leading to immune interferon production.

Animals↗
PubMed1983

Comparison of isoflurane and halothane when used to control intraoperative hypertension in patients undergoing coronary artery bypass surgery.

The hemodynamic effects of isoflurane and halothane when used to control intraoperative hypertension were evaluated in 20 patients undergoing coronary artery bypass grafting. The patients were anesthetized with flunitrazepam, fentanyl, pancuronium, and N2O-O2. Control measurements were made after skin incision. When mean arterial pressure increased to 110 mm Hg due to sternal spread or surgical manipulation of the aorta, isoflurane or halothane were used to return arterial pressure to control levels. Using a non-rebreathing system, inspired isoflurane concentrations of 1.5-2.0 vol% or halothane concentrations of 1.0-1.5 vol% were necessary. Measurements were repeated during the hypertensive episode and after treatment with isoflurane or halothane while surgical stimulation continued. Both inhalation anesthetics decreased arterial pressure to baseline values within 5-10 min. The lowering of arterial pressure with halothane was not accompanied by significant decreases in the elevated systemic vascular resistance and pulmonary capillary wedge pressure. Cardiac index and stroke volume index decreased markedly when halothane was used (18% and 25%, respectively). In contrast, isoflurane significantly decreased systemic vascular resistance (42%). This reduction of left ventricular afterload was associated with an increase in cardiac index (22%) and a decrease in left ventricular filling pressure. Heart rate did not change significantly. These findings indicate that isoflurane is superior to halothane for controlling intraoperative hypertension during coronary artery bypass surgery.

Adult↗
PubMed1982

Elicitation of delayed-type hypersensitivity to phosphorylcholine by monoclonal anti-idiotypic antibodies in an allogeneic environment.

Delayed-type hypersensitivity (DTH) to phosphorylcholine (PC) could be elicited by mixtures of monoclonal anti-idiotypic antibodies. Using this system in DTH transfers, the question was asked of whether anti-idiotypic antibodies could elicit antigen induced DTH in H-2-incompatible mice. Transfer of PC-activated BALB/c lymph node cells into BALB.K mice and subsequent elicitation with anti-idiotypic antibodies resulted in a positive DTH response. In contrast, elicitation with the antigen PC showed the expected H-2 restriction.

Animals↗
PubMed1982

Cell locomotion, a contributing factor in spread of the V2 rabbit carcinoma.

In histological sections of s.c. transplanted V2 rabbit carcinoma, single tumor cells and small tumor cell groups were found at some distance from the main tumor mass. This led to the question of whether locomotion could represent a contributing factor in the invasiveness of the V2 carcinoma. The behavior of V2 cells was therefore recorded under experimental conditions of increasing complexity: on glass, on the surface of a normal explanted rabbit mesentery, and on and within mesenteries of rabbit which had received intraperitoneal implants of V2 carcinoma. Time lapse cinematography showed the locomotory activity of V2 cells to be unaffected by the different substrates. In all instances the carcinoma cells migrated singly, on the two plane substrates also in small groups, under production of large leading lamellae. Intraperitoneally implanted V2 cells, in addition to their migration on the surface of the mesentery, penetrated into the interior with continuation of their characteristic translocative motility. Although cell locomotion could be established as a mechanism in the invasiveness of the V2 carcinoma, we do not consider it to be the only relevant factor. Tumor cell proliferation and destructive effects of proteinases appear to be other mechanisms contributing to the functional complex of local spread.

Animals↗
PubMed1982

["I wanted to survive better with the help of university studies"].

In West-Germany's Universities an interest in older students is emerging and the possibilities of integrating these students are discussed. This small study shows data about students born before 1937 who entered the University in the absence of special programs. The research interest was to learn something about the family and career background, the financial and social situation and the motivation of older students to continue their education at this University.

Aged↗
PubMed1982

Immune (y) interferon production by murine T cell lymphomas.

Various cloned murine T cell hybridomas and T cell lymphomas were evaluated for their ability to produce interferon (IFN). Two T cell tumor clones, L12-R1 and L12-R4, derived from the spontaneously in vitro transformed cell lines L12 originally established from fetal calf serum-primed C57BL/6 spleen cells were found to produce high IFN amounts upon mitogen stimulation. Phorbol myristate acetate led to maximal IFN production (2187 IU) by L12-R4 cells at concentrations of 2 x 10(-7) M, whereas concanavalin A and phytohemagglutinin induced lower levels of IFN synthesis (160 to 243 IU). None of the cell lines tested produced IFN constitutively or upon lipopolysaccharides stimulation. The IFN was characterized as immune (y) by being labile at pH 2 and neutralized by two rabbit anti-murine IFN-y antisera but not by antiserum to murine leukocyte (alpha) and fibroblast (beta) IFN. Phenotypic characterization of IFN-y-producing cells showed the L12 clones to be Thy-1.2+, Lyt-1+, 23-, and Ig-. The L12-R4 tumor cell therefore provide a unique source of IFN-y for purification, and may represent a useful model for studying the molecular mechanisms involved in T cell differentiation leading to IFN-y production.

Animals↗
PubMed1981

[Sports in old age - a contribution to the development of communicative abilities (author's transl)].

The intention of the present report is to show that particularly the negative self-assessment of older people produces disturbing developments even in their social relations. We proceed from the thesis that movement and game, i.e. the development of motor abilities forms the basis of the whole system of man. For this reason a socio-political education of the aged should include sports since it offers opportunities for developing a subjective and social awareness; in this context didactic-methodological approaches are developed.

Aged↗