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Biomedical subjects

E Klein

Publications and source records attributed to E Klein.

At least 505 records · Page 28Linked to original sources
PubMed1978

Artificial capillary perfusion cell culture: metabolic studies.

Glucose, lactic-acid, and oxygen metabolism of BHK and L929 cells on artificial capillary perfusion units have been studied using several different modes of perfusion. After 7 to 10 days, cells planted in the extracapillary compartment of culture units containing 80 to 150 fibers reached populations that used 0.073 +/- 0.025 mumol per min glucose and 0.76 +/- 0.26 microliter per min oxygen and excreted 0.078 +/- 0.038 mumol per min lactic acid. From these data it is estimated that these units contain approximately 2 x 10(7) cells. The metabolic rate of cultures perfused through the capillaries or through the extracapillary compartment was not affected significantly by change in flow rate except at perfusion flow rates less than or equal to 0.05 ml per min. The cell population, as measured by metabolic activity, did not increase significantly when the serum content of the medium was less than or equal to 1%. No major differences were found in glucose utilization rates of equal numbers of cells on artificial capillaries, on short-term suspension culture, or as monolayers in plastic flasks. Artificial capillary perfusion may provide a simple system for studying metabolism of mammalian cells in culture.

Cell Count↗
PubMed1978

EBV-related cytotoxicity of Fc receptor negative T lymphocytes separated from the blood of infectious mononucleosis patients.

Epstein-Barr virus (EBV) related specific killing was demonstrated previously in the T cell enriched subpopulations of blood lymphocytes of IM patients. In the present work we demonstrate that the cytotoxic cells belong to the Fc negative T subset. T cells in the blood of IM patients can be divided in 2 categories, 1 Fc positive with non discriminative cytotoxicity and the other, Fc negative with selective cytotoxicity against EBV genome carrying lymphoblastoid cell lines.

Cell Line↗
PubMed1978

Search for disease-related cytotoxicity in mammary tumor patients.

Blood lymphocytes from benign and malignant mammary tumor patients ahd healthy blood donors were tested for cytotoxicity against monolayer cell lines, including two which were derived from breast carcinomas. Generally, the T subset was not cytotoxic, and if so this was not restricted to the relevant cell lines. In accordance with previous results 'null' cells were most efficient in the seemingly non-selective cytotoxicity.

Adenofibroma↗
PubMed1978

Restricted autologous lymphocytotoxicity in lung neoplasia.

Blood lymphocytes from 47 patients with lung carcinoma have been tested for cytotoxicity against cells isolated from the autologous tumour. Significant cytotoxic potential was found in 15 cases. The effectors were also tested against allogeneic tumour targets from lung and other sites. Reactions were only rarely detected (2/32 positive against lung and 1/13 positive against non-lung cells). The restriction of cytotoxicity to the autologous combination was also apparent in in vitro-generated effectors. Blood lymphocytes were co-cultivated with autologous tumour and subsequently tested against autologous or allogeneic targets. Cytotoxicity was found in 13/17 lung tumours against autologous tumour, with no reactions recorded against allogeneic tumour targets, but one case positive against the K562 cell line. These data suggest either the expression of individually distinct antigens on human pulmonary neoplasms, or the requirement for histocompatibility between target and effector in cytotoxicity reactions in man, and therefore differ from previously described patterns of lymphocytotoxicity against human tumours.

Cell Line↗
PubMed1978

Natural species-restricted attachment of human and murine T lymphocytes to various cells.

Murine and human T lymphocytes bear on their surface a receptor that confers on them the ability to attach to a variety of target cells from the same species, derived in vivo and in vitro. Thymocytes and activated T cells attached readily to target cells, while blood T lymphocytes were able to do so only after the removal of sialic acid from either their cell membrane or that of the target cell. The natural attachment (NA) receptor and the corresponding site on the target cells are trypsin sensitive and the conjugation between them is temperature dependent. The phenomenon may be a manifestation of self recognition in a broader sense--recognizing the species--which is also reflected in the reactivity of mitogen-activated T cells and specific immune responses against allo- or other antigens expressed on target cell surfaces.

Animals↗
PubMed1978

Protective effect of murine sarcoma virus-superinfected mouse tumor cells against outgrowth of corresponding noninfected tumor.

Cultured lines of three newly established methylcholanthrene-induced tumors, MBK and MBL in CBA and MC57M in C57BL mice, and two mammary tumors, SBfnHC in CBA and S3W in ASW mice, were superinfected in vitro with Moloney sarcoma or leukemia virus (MSV, MLV). After superinfection, they expressed the Moloney virus-determined cell surface antigen (MCSA) and murine C-type viral p30 antigen, and produced NB-tropic C-type virus. The virus-infected tumors became more rejectable in normally susceptible syngeneic mice compared with the original noninfected line. There was no difference in 400-rad irradiated hosts. Mice that have rejected the virus-infected tumors showed an increased resistance to the corresponding noninfected tumor. The protective effect was comparable, with only one exception, to the immunizing effect of irradiated, noninfected cells. In vitro tests showed that small numbers of viable MSV-infected MBL generated cytotoxic spleen cells against both uninfected and MSV-infected MBL in syngeneic mice, while the same numbers of viable noninfected MBL did not induce cytotoxic cells. Relatively large numbers of irradiated MBL and MSV-MBL had a similar activity in inducing cytotoxic spleen cells against MBL in syngeneic hosts.

Animals↗
PubMed1978

Activation of neutrophilic granulocytes by products of human lymphocytes.

Materials produced by stimulated primary cultures of human lymphocytes and by a continuous human lymphoid cell line, RPMI 1788, were tested for granulocyte phagocytosis promoting activity. Blood lymphocytes of healthy donors were stimulated with tuberculin (PPD) or concanavalin A (con A) and the culture fluids collected after 3 days of in vitro incubation. Fluids of the lymphoid cell line were collected from 2-day-old cultures. All three kinds of preparations were found to induce a significant increase in neutrophilic granulocyte phagocytic activity. Studies on the kinetics of granulocyte activation revealed that it is a relatively rapid process, being maximal within 60-120 min. This is in contrast to the considerably slower activation of monocytes in a comparable system. Intracutaneous inoculation of the active materials in human volunteers resulted in reactions that grossly and histologically resembled accelerated delayed type hypersensitivity reactions.

Granulocytes↗
PubMed1978

Characteristics and in vitro growth influencing effects of the spleen cell population in a methylcholanthrene induced mouse sarcoma system.

Effects of immunization on the growth of the early passages of two methylcholanthrene induced mouse tumors, MC57 X and MC57 Y, were different. For tumor X, immunization resulted in complete protection, while tumor Y was enhanced. The enhancing effect was individual tumor specific. The spleens of tumor bearing animals were enlarged and the proportion of blasts, EAC- and EA-rosettes were increased. This was the case for the T cell enriched population also. In lesser extent, such findings were also obtained in the lymph nodes. The spleens of control and tumor bearer animals were tested for effect on the in vitro growth of tumor cells. From both sources non-adherent subpopulations enriched in C3 receptor bearing cells substantially reduced the number of tumor cells. Using the T cell fractions, only those derived from tumor bearer spleens were active. The in vitro effects on the growth of the two tumors were cross-reactive. T cells exhibiting growth inhibition in vitro were detectable 13 days after subcutaneous inoculation, when the tumor was already measurable, while earlier the T cells enhanced the growth. The outcome of the in vitro tests reflected only the tumorous status of the animal and did not relate to preimmunization.

Animals↗
PubMed1978

Human blood lymphocyte fractionation with special attention to their cytotoxic potential.

In studies concerning the natural cytotoxic activity of human blood lymphocytes we have found that: 1. T cell, which rosette with sheep erythrocytes can be separated by centrifuging on Ficoll the lymphocyte and erythrocyte mixture without previously pelleting and incubating in the cold. 2. Lysis of marker erythrocytes with ammonium chloride impairs the cytotoxic activity of lymphocytes. Incubation at 37 degrees C for 12 hr prior to the test restores the activity to some extent. 3. A high proportion of the so call "null" fraction i.e. cells remaining in the interface after removal of B cells (passage on nylon column) and sedimentation of E rosettes, sediments as rosettes with sheep EAC'indicating that these cells carry low density E and C3 receptors. Rosetting with SRBC or ox EAC' gave significantly lowr values. On a per cell basis the "null" fraction was the most efficient one in natural cytotoxicity. Depletion of cells with low affinity E or E and C3 receptors left highly active subfractions.

Ammonium Chloride↗
PubMed1978

Progress in hemodialyzers and membranes--the last 20 years.

The development of clinical dialyzers is traced over the past three decades. Beginning with the Kolff rotating device, the evolution of dialyzers has followed a path to reduce size, increase metabolite transport, and minimize blood losses. A combination of design innovations and membrane developments has been necessary to achieve the performance of current dialyzers. These include the development of thin-channel plate dialyzers, hollow-fiber membranes, and more permeable membranes. The development of better devices has been hindered by lack of complete understanding of physiological and biochemical needs for treatment of end stage renal patients. A backlog of engineering and materials information is available for future utilization when therapy needs are clarified. Future trends in membrane developments may include melt-extrudable and "non-isotropic" membranes.

History, 20th Century↗
PubMed1978

Continuous monitoring of urea levels during hemodialysis.

An ammonium ion-specific electrode system is evaluated for analysis of blood urea nitrogen from serum, plasma ultrafiltrate, or hemodialyzer dialysate fluid. The electrode shows a high sensitivity over clinically useful concentration ranges. Free serum ammonia, volatile amines, or urea ammonia after hydrolysis can be measured. In a double blind study excellent correlation was found for 187 blood urea nitrogen samples measured with the electrode with standard auto-analyzer techniques. Continuous monitoring of urea in dialysate fluid is described. Urea clearances were measured from dialysate effluent from an in vitro dialysis using conventional equipment. These values show excellent correlation to those from stnadard analysis methods. A continuous urea sensor for on-line hemodialysis application which can provide quantification of therapy is described.

Ammonia↗
PubMed1978

Continuous monitoring of urea and inorganic phosphate during hemodialysis: II. Clinical trials.

Ion-selective eletrodes have been used to monitor urea and inorganic phosphate removal during dialysis. The dialysate outlow concentrations from a single pass beside controller were used to compute instantaneous serum concentrations. The urea data are in agreement with a single pool reservoir model; the inorganic phosphate removal was not log-linear, indicating rate limiting intracompartmental transfer. The procedure can be applied to the computation of urea generation rates and thus provide information on the protein catabolism rates of the patient; in addition, the monitor provides continuous checks on the dialyzer performance.

Autoanalysis↗