Differences in vitro between fibroblast-like cells from cornea, heart, and skin of embryonic chicks

Populations of fibroblast-like cells of corneal stroma, heart ventricle, and back skin of day-14 embryonic chicks were grown in vitro as primary and secondary cultures and were found to differ from one another by several criteria. Such cells were obtained from tissues either directly (cornea) by dissection or indirectly (heart and skin) by the rapid adhesion of the fibroblast-like cells to glass and plastic substrata. Individual fibroblast-like cells of cornea and heart were distinguishable from one another during their first 24–48 h in vitro. The morphologies of the individual cels of these 2 populations became indistinguishable during logarithmic growth, although each could be distinguished from individual fibroblast-like cells of skin. When the cultures reached saturation, corneal cells formed a monolayer of randomly oriented polygonal cells; skin cells formed a monolayer of long, narrow, ragged cells in parallel arrays with occasional double-layering; and heart cells formed multilayers of criss-crossed cells whose broad, smooth outlines were in parallel array in each layer. Saturation densities of the 3 fibroblast-like populations were different: heart greater than skin greater than cornea. By 3 methods of assay the cells were found to be differentially sensitive to treatment with trypsin and EDTA, and to EDTA alone, heart cells consistently being the least sensitive. Taken together, these data suggest that fibroblast-like cell populations isolated from different tissues of a single organism are different from one another and thus may behave differently from one another during in vitro studies.

Peripheral blood B-lymphocyte abnormalities associated with hyperthyroidism of Graves' disease

Proportions of peripheral blood thymus-derived T lymphocytes (T cells) and bone-marrow-derived B-lymphocytes (B cells) were studied in twelve hyperthyroid patients and ninety-nine non-hyperthyroid control subjects including thirty-nine healthy individuals and sixty patients with various disorders. All hyperthyroid patients had Graves' disease and eight were untreated. The sheep erythrocyte (E)-rosetting technique was employed for enumeration of T cells and the immunofluorescent technique was used for identification of lymphocytes with surface immunoglobulins (SIg), a marker for B cells. The results showed that hyperthyroid patients had higher percentages of lymphocytes stainable for SIg, whereas their T-cell proportions were the same as our control values. In addition, approximately half or more of the fluorescein stainable lymphocytes reacted with each of the five antisera against individual heavy chain determinants, including the epsilon chain, indicating the presence of more than three Ig determinants on the same cell. The fluorescein-stainable cells did not form E rosettes. Blocking of the Fc receptor on lymphocytes by incubating the patients' cells with heat-aggregated human IgG or heated goat anti-bovine serum albumin (anti-BSA) failed to abolish the subsequent fluorescent staining of the cells. Incubation of patients' lymphocytes with non-fluorescent anti-epsilon inhibited the subsequent staining of cells with fluoresceinated anti-epsilon but not staining with fluoresceinated anti-mu or anti-gamma. Thus, the study revealed B-cell abnormalities associated with hyperthyroidism, manifested by the simultaneous presence of multiple Ig classes, including IgE, on a single B cell. Results of studies of incubation of the patients' plasmas with lymphocytes from health individuals and studies of SIg by overnight culture of the patients' lymphocytes with or without prior trypsinization suggested that the SIg was generated endogenously by the cell on which it resided.

Surface immunoglobulins of lymphocytes in plasmacytoma. V. The effect of RNA-rich extract from mouse plasmacytoma MOPC 104E on the immune response

BALB/c mice with the plasmacytoma MOPC 104E producing monoclonal IgM-lambda with antibody activity to alpha-1,3 dextran were found to have B lymphocytes with surface immunoglobulins with the immunochemical characteristics of 104E IgM capable of binding alpha-1,3 dextran. RNA extracted from this plasmacytoma induced the synthesis of such surface immunoglobulins on normal B lymphocytes in vitro and in vivo. Injection of 200 mug of MOPC 104E RNA into normal mice 72 hr prior to the administration of the antigen kept the immune response to dextran-S intact, but suppressed that to other antigens, such as DNP-Ficoll and LPS, T cell-independent antigens, and SRBC and BSA which are T cell-dependent. The effect of the RNA was abolished by RNase but not by pronase and DNase. RNA extracted from LPC-1 tumour (gamma2a-k without known antibody activity) significantly suppressed the immune response to dextran-S and to other antigens in normal mice. Thus, opposite effects of MOPC 104E RNA on the response to specific and non-specific antigens strengthen the hypothesis that the immune deficiency in plasmacytoma bearing mice is due to the conversion of normal surface immunoglobulin of a population of B lymphocytes to the idiotype of the respective myeloma globulin.

Passive immunity to murine plasmacytoma by rabbit antiidiotypic antibody to myeloma protein

Antiidiotypic antisera to LPC-1 and MOPC-300 plasmacytoma globulins were produced in rabbits by immunization with the corresponding antigen and exhaustive immunoabsorption with normal BALB/c plasma and other myeloma globulins. IgG fractions of these antisera when given intraperitoneally on three consecutive days after tumor implantation, protected the animal specifically from the grafting of the corresponding plasmacytoma or induced regression of the tumors after their initial grafting and growth. In vitro cytotoxicity of the antisera to plasmacytoma cells was not demonstrated. Plasma of the antisera-treated normal BALB/c mice, though containing antiidiotypic antibody in high titers (320-640), was not cytotoxic to tumor cells. The inhibitory effect on tumor growth can be considered the result of passive immunization against plasmacytoma with xenogeneic humoral antibody.

Changes in lymphocyte surface immunoglobulins in myeloma and the effect of an RNA-containing plasma factor

Patients with multiple myeloma have a reduced number of B lymphocytes with normal surface immunoglobulin. When, however, anti-idiotypic antiserums to the respective myeloma globulins were used for the visualization of surface immunoglobulin by indirect immunofluorescence, a large number of surface immunoglobulin carrying lymphocytes were detected. The possibility of absorption of these monoclonal surface immunoglobulins from the surrounding plasma was excluded by showing their resynthesis after removal from the cells by trypsinization. The change in the character of surface immunoglobulin was reproduced on normal lymphocytes with an RNA-rich extract from the plasma of patients with myeloma; this effect was inhibited by RNase and cycloheximide. These findings suggest the possibility that an RNA-containing plasma factor transmits information for synthesis of surface immunoglobulins between myeloma cells and normal lymphocytes. This mechanism may contribute to the dysfunction of B lymphocytes in patients with myeloma, leading to immunologic deficiency.

Myxedema ileus. A form of intestinal pseudo-obstruction

Myxedema ileus uncommonly complicates the hypothyroid state. It is a rare cause of intestinal pseudo-obstruction that can be reversed with thyroid hormone therapy. Our two patients with myxedema ileus had concurrent infection. Intestinal ileus was completely reversed with the administration of thyroid hormone.

Presence of brightly fluorescent material in testes of XX males

The case of a phenotypic male with a predominantly 46,XX karyotype is presented. Examination of quinacrine mustard stained frozen sections of testicular tissue revealed that 29% of Sertoli cells contained a brightly fluorescent spot, presumably representing the Y chromosome. Interestingly, these cells were the only X chromatin negative cells observed in the testis. It is concluded that it is hazardous to regard any case as a pure `XX male' without extensive study of all available tissues, including fluorescence of testicular tissue.

On the theory of ion transport across the nerve membrane. VI. Free energy and activation free energies of conformational change

Empirical functions, such as n(infinity)(V) and tau(n)(V) (of the Hodgkin-Huxley type), can be recast in terms of more fundamental functions F(V) (related to a conformational free energy change) and theta(V) (related to the corresponding free energies of activation). Examples of F(V) and theta(V) are given, for squid and frog node. F(V) is essentially a quadratic function of V. The possible molecular origin, for protein-like subunits, of the linear (e.g., net charge) and quadratic (e.g., polarizability) terms in F(V) is discussed. The F(V), theta(V) kind of analysis leads rather automatically to a simple explanation of the well-known approximate coincidence in location (V value) of the maximum in tau(n)(V) (time constant) and the steeply rising part of n(infinity)(V) (also m, 1 - h).

Cooperative effects in models of steady-state transport across membranes. 3. Simulation of potassium ion transport in nerve

An extremely simple membrane transport model simulates qualitatively the observed flux-potential curves for steady-state potassium ion transport across a nerve (squid) membrane in the special case of high external potassium ion concentration. The transporting units (protein molecules) in the model are assumed to exist in two different conformations, which interact cooperatively. The membrane potential induces a transition between the two conformations by virtue, primarily, of a polarizability difference in the two conformations. Differential proton binding may make an important contribution to this effect.

Cooperative effects in models of steady-state transport across membranes. I

Three simple models are discussed which show cooperative effects in the steady-state transport of neutral molecules across a membrane. The Bragg-Williams approximation is employed, and its limitations discussed. In this approximation to cooperative problems, the diagram method for the calculation of steady-state probabilities and fluxes can still be used. This paper is closely related to one by Blumenthal, Changeux, and Lefever, and provides the foundation for sequels on an oscillatory steady-state phase-transition model (part II) and on simple models possibly related to steady-state potassium ion transport across a nerve membrane (part III).

Flow through a collapsible tube. Experimental analysis and mathematical model

Flow through thin-wall axisymmetric tubes has long been of interest to physiologists. Analysis is complicated by the fact that such tubes will collapse when the transmural pressure (internal minus external pressure) is near zero. Because of the absence of any body of related knowledge in other sciences or engineering, previous workers have directed their efforts towards experimental studies of flow in collapsible tubes. More recently, some attention has been given towards analytical studies. Results of an extensive series of experiments show that the significant system parameter is transmural pressure. The cross-sectional area of the tube depends upon the transmural pressure, and changes in cross-section in turn affect the flow geometry. Based on experimental studies, a lumped parameter system model is proposed for the collapsible tube. The mathematical model is simulated on a hybrid computer. Experimental data were used to define the functional relationship between cross-sectional area and transmural pressure as well as the relation between the energy loss coefficient and cross-sectional area. Computer results confirm the validity of the model for both steady and transient flow conditions.