Role of Ly-6 in lymphocyte activation. II. Induction of T cell activation by monoclonal anti-Ly-6 antibodies

The Ly-6 locus controls the expression and/or encodes for alloantigenic specificities found primarily on subpopulations of murine T and B lymphocytes. We have recently identified and characterized a new rat mAb, D7, that recognizes a nonpolymorphic Ly-6 specificity. After crosslinking by anti-Ig reagents or by Fc receptor-bearing accessory cells, mAb D7 could induce IL-2 production from T cell hybridomas, and in the presence of PMA could trigger a vigorous proliferative response in resting peripheral T cells. The addition of mAb D7 to cultures of antigen- and alloantigen-, but not mitogen-stimulated T cells resulted in a marked augmentation of the proliferative response. A number of other well-characterized mAbs to Ly-6 locus products could also stimulate a T cell proliferative response after crosslinking by anti-Ig and in the presence of PMA. These results strongly suggest that Ly-6 molecules may play a critical role in the T cell activation cascade, either as receptors for an unidentified soluble or cell-associated ligand or as transducing molecules that modulate signals initiated by antigen stimulation of the T3-Ti complex.

Nephrotic syndrome associated with a clonal T-cell leukemia of large granular lymphocytes with cytotoxic function

A 51-year-old man presented with a T-cell leukemia of large granular lymphocytes and rapidly developed a nephrotic syndrome due to presumptive minimal-change glomerulopathy. The E-rosette+, Ia+ cells demonstrated cytotoxic activity similar to that of natural killer lymphocytes but lacked other T-subset markers, except that one third of them bore Fc(IgG) receptors. Cytogenetic analysis revealed loss of chromosome 10 and the translocation (1;10)(p11;q11) in all metaphases. Regression of the leukemia after chemotherapy was accompanied by a dramatic resolution of the nephrotic syndrome, suggesting that the activated granular lymphocytes induced the renal lesion. The close association of a clonal T-lymphoproliferative disorder with minimal-change nephrotic syndrome lends further support to current views implicating activated T cells or their products in the pathogenesis of this glomerulopathy.

The question of ocular tolerance to intravitreal liquid silicone. A long-term analysis

The authors report a retrospective review of 407 eyes that received intravitreal liquid silicone between 1961 and 1984. Initial anatomical success was noted in 270 eyes (66.3%), while initial functional success was achieved in 103 eyes (25.3%). Ten years postoperatively, approximately half of the eyes with initial functional success still had functional vision (49.2%). These eyes had less advanced proliferative vitreoretinopathy and fewer inferior breaks than others. Recurrent retinal detachment rather than late complications was the predominant cause of functional failure in those eyes losing functional vision in less than ten years postoperatively. Late complications were common and frequently required therapeutic intervention. Intravitreal liquid silicone was of great benefit to many monocular patients, but of little benefit to the binocular patients in our series.

Kinetics of Energy Flow in the Phycobilisome Core

Light energy absorbed by the 576 bilin chromophores in the six rods of the phycobilisome of the cyanobacterium Synechocystis 6701 is funneled into a 1.5 x 10(6) dalton core. The 72 bilins of the core function as a single unit with respect to the rate-limiting processes for energy flow within these particles.

Role of the L3T4-antigen in T cell activation. II. Inhibition of T cell activation by monoclonal anti-L3T4 antibodies in the absence of accessory cells

We have used two monoclonal antibodies (Mab) to the L3T4 antigen to reexplore the role of this molecule in the process of T cell activation. Both Mab (Gk1.5 and 2B6) were capable of inhibiting Con A-induced IL 2 production by a number of antigen-specific T cell hybridomas in an assay system that was free of major histocompatibility complex (MHC) class II antigen-bearing cells. The inhibition produced by the anti-L3T4 Mab was specific, because other Mab to cell surface antigens expressed on the hybridomas were without inhibitory effects. These studies rule out the possibility that the mechanism of inhibition by anti-L3T4 in this model is mediated by blocking interaction of L3T4 with MHC class II products. Taken together, these results and those of other groups of investigators, are most compatible with a dual function for L3T4 in T cell activation. L3T4 might first interact with MHC class II molecules or other molecules on target or accessory cells; L3T4 would subsequently transmit a signal that would regulate the activation process. Mab to L3T4 might exert inhibitory effects at one or both of these steps.

Role of the L3T4-antigen in T cell activation. II. Inhibition of T cell activation by monoclonal anti-L3T4 antibodies in the absence of accessory cells

We have used two monoclonal antibodies (Mab) to the L3T4 antigen to reexplore the role of this molecule in the process of T cell activation. Both Mab (Gk1.5 and 2B6) were capable of inhibiting Con A-induced IL 2 production by a number of antigen-specific T cell hybridomas in an assay system that was free of major histocompatibility complex (MHC) class II antigen-bearing cells. The inhibition produced by the anti-L3T4 Mab was specific, because other Mab to cell surface antigens expressed on the hybridomas were without inhibitory effects. These studies rule out the possibility that the mechanism of inhibition by anti-L3T4 in this model is mediated by blocking interaction of L3T4 with MHC class II products. Taken together, these results and those of other groups of investigators, are most compatible with a dual function for L3T4 in T cell activation. L3T4 might first interact with MHC class II molecules or other molecules on target or accessory cells; L3T4 would subsequently transmit a signal that would regulate the activation process. Mab to L3T4 might exert inhibitory effects at one or both of these steps.

Characterization and partial purification of a specific interleukin 2 inhibitor

To investigate the mechanisms that regulate the action of interleukin 2 (IL 2) and possibly limit its activity, we screened supernatants of mouse spleen cell cultures which had been stimulated with concanavalin A (Con A) for their ability to inhibit IL 2-mediated proliferation of a cloned IL 2-dependent line. Inhibitory activities with m.w. of 10,000 to 12,000 and 60,000 to 80,000 daltons could be identified in supernatants of both L3T4+ and Ly-2+ T cells, but not in supernatants of Con A or lipopolysaccharide-stimulated B cells. Maximal inhibitory activity was observed after 3 to 4 days of stimulation, and this inhibitory activity could be overcome by increasing the stimulatory concentration of IL 2. When the factor was further purified by reverse-phase high pressure liquid chromatography, it eluted as a single peak with an m.w. of 11,000 to 12,000 daltons which inhibited IL 2- but not IL 3-dependent proliferation. The mechanisms by which this new lymphokine might play in the control of the clonal expansion of T lymphocytes are discussed.

Influence of accessory cell and T cell surface antigens on mitogen-induced IL 2 receptor expression

We have assessed the inhibitory effects of various monoclonal antibodies on the expression of the IL 2 receptor. Anti-LFA-1, but not anti-Ly-2, markedly inhibited the induction of the IL 2 receptor on the Ly-2+ subset. T-depleted spleen cells, L cells, and B lymphoma cells all functioned as potent accessory cells (AC) for the induction of the IL 2 receptor on L3T4+ T cells. Anti-LFA-1 inhibited the induction of the IL 2 receptor irrespective of the type of AC used. Anti-L3T4 only inhibited the induction of IL 2 receptor expression when L cells were the source of AC. The inhibitory capacity of anti-L3T4 was not related to the expression of Ia on the AC population, because the magnitude of inhibition was comparable in cultures containing either Ia+ or Ia- L cells, whereas no inhibition was seen with either Ia+ or Ia-B lymphoma cells. We conclude from these studies that LFA-1 plays a critical role in mitogen-induced activation of both T cell subsets by promoting both T-AC and T-T interactions. Although anti-L3T4 can inhibit T cell activation in the absence of the recognition of Ia, the mechanism of inhibition and the proposed target molecule for L3T4 on the AC or the T cell have not been determined in our studies. A number of different models for the function of this cell surface antigen are discussed.

Characterization and partial purification of a specific interleukin 2 inhibitor

To investigate the mechanisms that regulate the action of interleukin 2 (IL 2) and possibly limit its activity, we screened supernatants of mouse spleen cell cultures which had been stimulated with concanavalin A (Con A) for their ability to inhibit IL 2-mediated proliferation of a cloned IL 2-dependent line. Inhibitory activities with m.w. of 10,000 to 12,000 and 60,000 to 80,000 daltons could be identified in supernatants of both L3T4+ and Ly-2+ T cells, but not in supernatants of Con A or lipopolysaccharide-stimulated B cells. Maximal inhibitory activity was observed after 3 to 4 days of stimulation, and this inhibitory activity could be overcome by increasing the stimulatory concentration of IL 2. When the factor was further purified by reverse-phase high pressure liquid chromatography, it eluted as a single peak with an m.w. of 11,000 to 12,000 daltons which inhibited IL 2- but not IL 3-dependent proliferation. The mechanisms by which this new lymphokine might play in the control of the clonal expansion of T lymphocytes are discussed.

Influence of accessory cell and T cell surface antigens on mitogen-induced IL 2 receptor expression

We have assessed the inhibitory effects of various monoclonal antibodies on the expression of the IL 2 receptor. Anti-LFA-1, but not anti-Ly-2, markedly inhibited the induction of the IL 2 receptor on the Ly-2+ subset. T-depleted spleen cells, L cells, and B lymphoma cells all functioned as potent accessory cells (AC) for the induction of the IL 2 receptor on L3T4+ T cells. Anti-LFA-1 inhibited the induction of the IL 2 receptor irrespective of the type of AC used. Anti-L3T4 only inhibited the induction of IL 2 receptor expression when L cells were the source of AC. The inhibitory capacity of anti-L3T4 was not related to the expression of Ia on the AC population, because the magnitude of inhibition was comparable in cultures containing either Ia+ or Ia- L cells, whereas no inhibition was seen with either Ia+ or Ia-B lymphoma cells. We conclude from these studies that LFA-1 plays a critical role in mitogen-induced activation of both T cell subsets by promoting both T-AC and T-T interactions. Although anti-L3T4 can inhibit T cell activation in the absence of the recognition of Ia, the mechanism of inhibition and the proposed target molecule for L3T4 on the AC or the T cell have not been determined in our studies. A number of different models for the function of this cell surface antigen are discussed.

Effects of propranolol on atherogenesis in the cholesterol-fed rabbit

These studies have examined the effects of dl-propranolol, d-propranolol, and metoprolol on aortic atherogenesis in the cholesterol-fed rabbit and have correlated the vascular effects of the drugs with their influence on blood pressure, plasma lipids and lipoproteins, arterial metabolism, and arterial permeability. dl-Propranolol, and, to a lesser extent, d-propranolol, used in clinically relevant doses of 5 mg/kg body weight per day, inhibited the development of aortic atherosclerosis in association with significant reductions in aortic free and esterified cholesterol content. No significant effects of the drugs on blood pressure or on the total amounts or types of circulating lipoproteins were apparent. Accumulation of cholesterol in the liver and adrenal gland was not influenced by propranolol. Aortic acyl CoA:cholesterol acyltransferase and lysosomal enzyme activities were reduced by propranolol administration, but the inhibition may have been secondary to the lesser degrees of atherosclerosis and cholesterol accumulation present. In vitro inhibition of acyl CoA:cholesterol acyltransferase activity by either dl- or d-propranolol was also observed, but occurred only at propranolol concentrations of 10(-3) M or greater. Treatment with dl-propranolol had no significant effect on the rate of transport of labeled albumin across the isolated carotid artery of cholesterol-fed rabbits. Metoprolol administration (6.25 mg/kg body weight per day) had no significant influence on atherogenesis or arterial metabolism in this model. The results suggest that propranolol inhibits in part the development of atherosclerosis in the cholesterol-fed rabbit, and that the effect may be related to a direct action on the arterial wall.

Simulating refractive errors: source and observer methods

There are two principal methods of simulating refractive errors. Either the retinal image can be defocused by an optical system, usually a positive lens, placed in front of an observer's eye (observer method), or the source of the retinal image can be defocused as it is projected onto a screen or photograph (source method). There are significant differences between the two methods, differences that make it difficult to compare results. However, the source method, which is the more artificial, seems to be superior for a number of reasons. The results of these two methods can be compared using a common or interchangeable parameter for specifying the level of defocus. A convenient parameter is the size of the defocused image of a point, measured either in image space (linear or angular diameter on the retina) or in object space (angular diameter of the blur disc projected back into object space), with the angular diameter measured from the respective nodal point of the eye. Methods of measuring the angular blur-disc diameter for both methods are discussed and the validity of the formula omega = D delta L, is investigated, where omega is the angular diameter of the blur disc, D is the observer's pupil diameter, and delta L is the dioptric defocus.

The murine IL 2 receptor. II. Monoclonal anti-IL 2 receptor antibodies as specific inhibitors of T cell function in vitro

We assessed the dependency of a variety of immune responses for IL 2 in vitro by using anti-IL 2 receptor monoclonal antibodies as specific inhibitors of IL 2 function. The generation of allogeneic cytotoxic T lymphocyte (CTL) responses and maximal thymocyte proliferation to phytohemagglutinin (PHA) and IL 1 was readily susceptible to inhibition by these antibodies. Furthermore, the IL 2 receptor-positive, IL 2-responsive cell in the CTL cultures expressed killer cell activity. A greater variability in susceptibility to anti-IL 2 receptor antibody inhibition was noted for proliferation of T cells to concanavalin A, PHA, or allogeneic cells. Under certain conditions, however, each of these responses was almost completely inhibited. In most instances, the failure to block a response could be accounted for by either high levels of endogenous IL 2 production or high density of cell surface IL 2 receptors, which represent two known variables that influence the level of inhibition by these antibodies. Analysis of IL 2 receptor expression by mitogen-stimulated T cells suggested that accessory cells may play a role in the optimal expression of the IL 2 receptor. These experiments demonstrate that IL 2 is the predominant growth factor by which T lymphocytes proliferate, but do not exclude the possibility of an IL 2-independent pathway for growth.

The murine IL 2 receptor. II. Monoclonal anti-IL 2 receptor antibodies as specific inhibitors of T cell function in vitro

We assessed the dependency of a variety of immune responses for IL 2 in vitro by using anti-IL 2 receptor monoclonal antibodies as specific inhibitors of IL 2 function. The generation of allogeneic cytotoxic T lymphocyte (CTL) responses and maximal thymocyte proliferation to phytohemagglutinin (PHA) and IL 1 was readily susceptible to inhibition by these antibodies. Furthermore, the IL 2 receptor-positive, IL 2-responsive cell in the CTL cultures expressed killer cell activity. A greater variability in susceptibility to anti-IL 2 receptor antibody inhibition was noted for proliferation of T cells to concanavalin A, PHA, or allogeneic cells. Under certain conditions, however, each of these responses was almost completely inhibited. In most instances, the failure to block a response could be accounted for by either high levels of endogenous IL 2 production or high density of cell surface IL 2 receptors, which represent two known variables that influence the level of inhibition by these antibodies. Analysis of IL 2 receptor expression by mitogen-stimulated T cells suggested that accessory cells may play a role in the optimal expression of the IL 2 receptor. These experiments demonstrate that IL 2 is the predominant growth factor by which T lymphocytes proliferate, but do not exclude the possibility of an IL 2-independent pathway for growth.

Identification and preliminary mapping with monoclonal antibodies of a herpes simplex virus 2 glycoprotein lacking a known type 1 counterpart

The properties of herpes simplex virus 2 (HSV-2)-specific proteins reactive with monoclonal antibody H966 derived from mice immunized with HSV-2 strain G are reported. The reactive proteins contained in infected cell lysates subjected to electrophoresis in denaturing gels and transferred to nitrocellulose sheets form a relatively sharp band characteristic of Mr 124,000 proteins and a diffuse, more slowly migrating band. Antigens reactive with H966 were detected on the surface of viable, unfixed cells. The electrophoretic mobility of the H966-reactive proteins made in the presence of tunicamycin was more rapid than that of the proteins made in the absence of the drug. Direct evidence that the HSV-2-specific antigen was a glycoprotein emerged from purification of [14C]glucosamine-labeled proteins with similar electrophoretic mobilities by immunoabsorption to H966 bound to Sepharose beads. Analyses of the reactivity of HSV-1 X HSV-2 recombinants indicated the gene specifying the glycoprotein maps in the S component of the DNA. The glycoprotein detected by H966 has no known counterpart in HSV-1 and corresponds to the glycoprotein previously designated as gC of HSV-2 and reported to map to the right of gC specified by HSV-1. Inasmuch as an HSV-2 gene colinear with HSV-1 gC has been reported to specify a glycoprotein currently designated as gC of HSV-2 by Para et al. [J. Virol. 45, 1223-1227 (1983)], the glycoprotein identified by H966 should be designated as gG.

Fine specificity of cloned insulin-specific T cell hybridomas: evidence supporting a role for tertiary conformation

Two groups of cloned insulin-specific T cell hybridomas were derived from the fusion of (BALB/c X A/J)F1 T cells with the BW5147 tumor line. Group I responded only to the immunogen pork insulin and failed to respond to rat insulin, which differs only at amino acids A4 and B3. The second group of T cell hybridomas exhibited a broader pattern of reactivity to heterologous insulins because they could be stimulated with the B chain-identical pork, beef, sheep, and human insulins, as well as by isolated oxidized B chain. These hybridomas, however, displayed a much greater reactivity to pork insulin than to beef insulin or to the oxidized B chain. Comparison of the reactivity profiles of these two groups of hybridomas with the three-dimensional structure of the insulin molecule strongly suggested that group I cells were recognizing an immunogenic moiety composed of residues A4 and/or B3 in association with A chain loop determinants and that group II hybrids recognized a moiety composed of the amino acid sequence of the B chain and the A chain loop. Both groups of hybrids were restricted to the high-responder I-Ad allele but could be distinguished by their pattern of alloreactivity. We were unable to show any effect of a panel of monoclonal anti-insulin antibodies on the induction of interleukin 2 secretion by these hybridomas or to demonstrate the presence of idiotypic determinants on these T hybrids by using a panel of anti-idiotypic reagents raised against the monoclonal anti-insulin antibodies.

Fine specificity of cloned insulin-specific T cell hybridomas: evidence supporting a role for tertiary conformation

Two groups of cloned insulin-specific T cell hybridomas were derived from the fusion of (BALB/c X A/J)F1 T cells with the BW5147 tumor line. Group I responded only to the immunogen pork insulin and failed to respond to rat insulin, which differs only at amino acids A4 and B3. The second group of T cell hybridomas exhibited a broader pattern of reactivity to heterologous insulins because they could be stimulated with the B chain-identical pork, beef, sheep, and human insulins, as well as by isolated oxidized B chain. These hybridomas, however, displayed a much greater reactivity to pork insulin than to beef insulin or to the oxidized B chain. Comparison of the reactivity profiles of these two groups of hybridomas with the three-dimensional structure of the insulin molecule strongly suggested that group I cells were recognizing an immunogenic moiety composed of residues A4 and/or B3 in association with A chain loop determinants and that group II hybrids recognized a moiety composed of the amino acid sequence of the B chain and the A chain loop. Both groups of hybrids were restricted to the high-responder I-Ad allele but could be distinguished by their pattern of alloreactivity. We were unable to show any effect of a panel of monoclonal anti-insulin antibodies on the induction of interleukin 2 secretion by these hybridomas or to demonstrate the presence of idiotypic determinants on these T hybrids by using a panel of anti-idiotypic reagents raised against the monoclonal anti-insulin antibodies.

Herpes zoster ophthalmicus with contralateral hemiparesis. A case report and review of the literature

An 80-year-old man developed right herpes zoster ophthalmicus complicated by contralateral hemiparesis after right cataract extraction. Although herpes zoster ophthalmicus is a frequent occurrence among the elderly, the association with contralateral hemiparesis is probably overlooked by many ophthalmologists. A review of the literature has been made to outline the etiology of this problem and to make diagnosis more likely. The varicella virus probably spreads in a retrograde fashion from the gasserian ganglion toward the cavernous sinus to involve cranial nerves 3, 4, or 6. Involvement of the ipsilateral carotid arterial system by the progressive inflammatory reaction can result in the contralateral hemiparesis. Standard therapy includes topical steroids and topical antibiotics for the ocular and surface lesions. The efficacy of systemic steroids to minimize the hemiparesis is still in question.

Resistance to hepatotoxins acquired by hepatocytes during liver regeneration

The appearance of resistance to a number of hepatotoxins in primary cultures of hepatocytes prepared at various time intervals up to 2 weeks after partial hepatectomy is the major focus in this study. Resistance to the cytocidal effect of aflatoxin B1, 2-acetylaminofluorene, N-hydroxy-2-acetylaminofluorene, methotrexate, or methyl methanesulfonate shows a progressive increase until 48 hr and then returns to the resting level of susceptibility by 2 weeks. The genesis of mutagens from 2-acetylaminofluorene and aflatoxin B1 by S-9 liver fractions shows a decrease from and return to control values after partial hepatectomy that parallels the resistance. The levels of total cellular cytochromes P-450 also decrease following partial hepatectomy and remain from 28 to 36% less than those of controls for at least 1 week. The glutathione and total soluble sulfhydryl ("glutathione") content increase following partial hepatectomy, and the pattern is consistent with a partial role for glutathione in the resistance phenomenon as it relates to 2-acetylaminofluorene. The possible relationship between resistance to the cytocidal effects in vitro and the resistance to inhibition of cell proliferation in vivo during liver carcinogenesis is discussed.

Continuous five-day infusion of PALA and 5FU: a pilot phase II trial

In order to determine whether a simultaneous infusion of N-(phospho-n-acetyl)-L-aspartic acid (PALA) was able to increase the rate of antitumor response to 5-fluorouracil (5-FU), a pilot study was conducted. Of 10 evaluable patients with previously drug-untreated colorectal carcinoma, there were only two partial responses, lasting 2.3 and 1.6 months. No partial responses were observed in three evaluable patients with soft tissue sarcomas. The dose-limiting toxicity was dermatitis. The simultaneous infusion of PALA and 5-FU is not likely to produce a high number of antitumor responses of long duration in patients with colorectal carcinoma.

Nature of the antigenic complex recognized by T lymphocytes. VIII. Specific inhibition of the stimulatory capacity of antigen-pulsed hapten-modified peritoneal exudate cells by anti-hapten antibody

When macrophages which were pulsed with soluble protein antigens and then modified with 2,4,6-trinitrobenzenesulfonic acid (TNBS) were cultured with primed T cells in the presence of anti-2,4,6-trinitrophenyl (TNP) antiserum, a marked inhibition of the T cell proliferative response specific for the soluble protein antigen under study was observed. Inhibition of the proliferative response required that the protein antigen under study be easily susceptible to conjugation with TNBS. A lag period of 1-3 h must elapse following pulse exposure to the protein antigen and prior to TNP modification for anti-TNP antibody to exert an inhibitory effect, which suggests that processing of antigen in an intracellular site might occur with subsequent reexpression of antigen on the macrophage surface. It was hypothesized that anti-TNP antibody inhibits T cell proliferation by capping and shedding of TNP-modified determinants of the nominal antigen as well as TNP-modified cell surface proteins from the macrophage membrane. The failure of others to demonstrate an effect of anti-antigen antibody on T cell activation can best be explained as secondary to the low density of antigenic determinants on the macrophage membrane with resultant low-affinity binding of antibody to antigen.

Isocratic high-performance liquid chromatographic method for the determination of tricyclic antidepressants and metabolites in plasma

An isocratic high-performance liquid chromatographic method for the determination of six tricyclic antidepressants and their major metabolites is presented. Hexane containing 0.5% diethylamine was used as an extraction solvent to minimize adsorption onto glass. A reversed-phase cyanopropylsilane column was used with a mobile phase consisting of 70% acetonitrile and 30% 0.03 M acetate buffer, pH 7.0. Good identification and quantitation were obtained by the use of both UV detection at 245 nm and spectrofluorometric detection with an excitation wavelength of 276 nm and an emission filter with a 370-nm cutoff. A minimum detectable limit of less than 5 ng/ml of plasma is possible with this system. The reproducibility and precision of the method are shown from the analysis of samples containing 20-400 ng/ml in plasma.

Induction of transplantation tolerance in guinea pigs by spleen allografts. II. Responses in the mixed leukocyte reaction correlate with the tolerant state

We have developed a model for the induction of transplantation tolerance in the guinea pig by vascularized spleen allografts. Spleen allografts from strain 13 to strain 2 hosts frequently survived in healthy recipients without clinical GVHD or induced clinical GVHD. (2 x 13)F1 to strain 2 spleen allografts survived indefinitely without inducing GVHD. In contrast, strain 2 spleen allografts were rejected by strain 13 hosts. An excellent correlation was observed between the clinical course and the degree of reactivity to donor strain stimulator cells in the MLR. Animals that had rejected their grafts had normal or enhanced proliferative responses in the MLR. Strain 2 hosts with long-term surviving strain 13 or (2 x 13)F1 grafts had markedly suppressed anti-13 responses. Animals with GVHD had a suppressed MLR toward donor strain stimulator cells with simultaneous reactivity to host strain stimulator cells. Cells capable of suppressing the response of normal host strain cells to donor strain stimulators were present in some long-term surviving animals and may be responsible in part for the maintenance of the tolerant state.

Induction of transplantation tolerance in guinea pigs by spleen allografts. II. Responses in the mixed leukocyte reaction correlate with the tolerant state

We have developed a model for the induction of transplantation tolerance in the guinea pig by vascularized spleen allografts. Spleen allografts from strain 13 to strain 2 hosts frequently survived in healthy recipients without clinical GVHD or induced clinical GVHD. (2 x 13)F1 to strain 2 spleen allografts survived indefinitely without inducing GVHD. In contrast, strain 2 spleen allografts were rejected by strain 13 hosts. An excellent correlation was observed between the clinical course and the degree of reactivity to donor strain stimulator cells in the MLR. Animals that had rejected their grafts had normal or enhanced proliferative responses in the MLR. Strain 2 hosts with long-term surviving strain 13 or (2 x 13)F1 grafts had markedly suppressed anti-13 responses. Animals with GVHD had a suppressed MLR toward donor strain stimulator cells with simultaneous reactivity to host strain stimulator cells. Cells capable of suppressing the response of normal host strain cells to donor strain stimulators were present in some long-term surviving animals and may be responsible in part for the maintenance of the tolerant state.

Inexpensive fiber optic two-dimensional densitometer for the high-resolution quantitation of autoradiogram grain densities

The design and construction of a simple, low cost high performance fiber optic 2-dimensional microdensitometer is described. With this instrument the film to be quantitated is placed upon a back-lit frosted glass bench and scanned with an optic fiber probe attached to a transparent micromanipulator. The emerging light is transported by the fiber to the photocell of a direct reading spectrophotometer. The resulting numerical data can either be transcribed, portrayed on a recorder or entered into the memory of a microdata processor for further analysis and comparisons. The instrument was sensitive to very small differences in optical density and could resolve lines 100 but not 30 micrometers apart. It was precise, reliable and easy to build. With the use of this equipment many previously undetected, significant local brain glucose utilization differences were quantitated in groups of unrestrained rodents, maintained in several behavioral states.

Medical staff and hospital administration uses of discharge abstract data

In summary, this article suggests several useful approaches whereby physicians and hospital administrators can efficiently sort through large amounts of discharge abstract data to identify problem areas, particularly those concerning quality of care and utilization of services, and to formulate strategies for improvement. Approaches and steps suggested include: . Review objectives-determining variables of greatest concern; . Standards-determining acceptable values or levels of performance; . Focus of review-determining the unit of review, such as specific departments, diseases, or physicians; and . Quality and reliability of discharge abstract data-determining the data to use by undertaking four levels of edits: technical edits, logical edits, ratio edits, and categorical edits. A model flowchart provided in this article serves as a conceptual framework by which potential problem areas can be studied during a patient's hospitalization to precisely identify the interaction, the time, and the cause/association of the problem.

Measurement of temperature in flames using laser induced fluorescence spectroscopy of OH

A technique for measuring translational flame temperature utilizing the laser induced fluorescence spectrum of OH is demonstrated. The method is based on matching the observed spectrum to a numerical model in which the detailed balance temperature is a parameter. The precision of the method exceeds that of the line reversal technique. Accuracy is limited by the calibration source and the validity of the numerical rotational relaxation rate model.

Laser excitation dynamics of OH in flames

The response of OH in flames to laser excitation is studied in some detail. The population balance equations are solved numerically using an empirical model for the rotational relaxation rates. The empirical model parameters are fit to experimental spectra using a linear regression procedure and the resulting description of OH behavior is shown to be satisfactory to within the precision of the data. The model is then used to recover branching ratios for a number of flame conditions.

Important issues in the drug treatment of schizophrenia

The large body of research demonstrating the effectiveness of antipsychotic drugs in the treatment of acute schizophrenia is selectively reviewed. Research evidence relevant to the following issues is assessed; indications for selective treatment; characteristics of drug responders and nonresponders; indications for high dosage phenothiazine treatment; indications for maintenance therapy; benefits and risks of antipsychotic drugs. Recommendations are made concerning areas of psychopharmacologic research that require further development.

Specific ionic interactions and solubility activity product of caesium perrhenate at 298.10 K

The solubilities of caesium perrhenate in aqueous CsCl, NaCl, KCl and KReO4 solutions at 298.10 K are reported. The solubility activity product for CsReO4 was determined by using extrapolation functions involving two different mean ionic activity coefficient expressions and the results were compared; the total ionic strengths of all the saturated perrhenate solutions were less than 0.1 mol dm-3. One of these expressions used is that proposed recently by Panckhurst and Macaskill1,2 which is an extension of Guggenheim's approach,3,4 specific ionic interactions in aqueous solutions being explicitly taken into account. Its use led to more consistent values for the solubility activity product for CsReO4 than those obtained with the other expression which does not incorporate specific interaction parameters. Values of specific ionic interaction parameters for caesium, potassium and sodium perrhenates in dilute aqueous mixtures with CsCl, KCl, KReO4, KI or NaCl are also reported.

Enhanced primary resistance to Listeria monocytogenes in T cell-deprived mice

The present studies reinvestigate the role of the T cell in the development of resistance to Listeria monocytogenes. Doubly thymus-deprived adult thymectomized irradiated bone marrow-reconstituted mice (D-AT × BM) were prepared using anti-theta serum-treated bone marrow from AT × BM donors for reconstitution. The growth of the bacteria in spleens and livers of D-AT × BM was inhibited and such animals survived infection with doses which were lethal to normal mice. Since the D-AT × BM animals were T cell-depleted, as evidenced by (a) absence of theta-positive cells in their spleens; (b) inability to mount a primary humoral response to a T-dependent antigen and (c) failure to reject H-2 incompatible skin allografts, their antibacterial resistance was not due to the presence of a residual T-cell population. Further evidence of T-cell depletion in these animals was furnished by the findings that, despite their resistance to L. monocytogenes, they failed to exhibit a delayed hypersensitivity reaction to Listeria antigens, their splenocytes were unable to transfer resistance to naïve hosts and they did not develop an anamnestic response upon secondary challenge.

We concluded from these findings that primary antibacterial resistance to L. monocytogenes need not necessarily depend on the development of specific cell-mediated immunity although under normal circumstances these two processes develop in chronological association. The increased resistance of D-AT × BM animals is interpreted as being due to the enhancement of bactericidal activity of mononuclear phagocytes, possibly caused by the removal of a regulatory T-cell population. This population seems to be radiosensitive and spleen-seeking and requires an intact spleen to mediate its effect.

Subcellular localization of gamma-glutamyl carboxypeptidase and of folates

The subcellular distributions of glutamyl carboxypeptidase, folate specific activities, and radioactive metabolites of injected [3H] folic acid were studied in rat liver. The specific activity of glutamyl carboxypeptidase in the lysosomal fraction was near or greater than four times that in the other subcellular fractions. The specific activity of folates was highest in the soluble fraction (102 ng folate/mg protein) and lowest in the microsomal fraction (22 ng folate/mg protein). Nuclear, mitochondrial, and lysosomal folates were 95% folate polyglutamates, and microsomal and soluble folates were 85--90% folate polyglutamates. Injected [3H] folic acid was initially concentrated in the microsomal fraction, as measured by 3h cpm per ng folate. Initially, injected [3H] folic acid was found converted to folate penta- and hexaglutamates in all fractions to a similar extent except in the microsomes where the percentage conversion was much less, as measured by the percentage of total 3H cpm determined to be [3H] folate penta- and hexaglutamates. At 24 h, the conversion of [3H] folates to penta- and hexaglutamates in each fraction was less than that found for the endogenous folates. Injected [3H] folic acid after 2h was found to consist of 94% reduced folates in the soluble fraction, 56% in the mitochondrial, 55% in the nuclear, 20% in the lysosomal, and 15% in the microsomal fraction.

Rescue of a rat tropic rat hepatoma virus pseudotype Kirsten sarcoma virus by co-cultivation of hepatoma tissue culture cells with K-NRK cells

A rat tropic rat hepatoma virus pseudotype Kirsten sarcoma virus has been rescued from a co-culture of rat hepatoma tissue culture cells, HTC-HI, with Kirsten murine sarcoma transformed non-producer rat kidney cells (K-NRK). The virus complex, RHHV-KiMSV, released from the co-culture exhibited cell transformation ability on normal rat kidney (NRK) cells and showed a restricted host range limited to rat embryo fibroblasts and other normal rat cell lines. Evidence derived from indirect immunofluorescence assays demonstrated the association of rat helper virus specific gs-I and gs-3 antigens with RHHV-KiMSV transformed cells. RHHVKiMSV is currently being cultured at a titre as high as 10(4) f.f.u./ml in tissue culture, and thus offering opportunity for biochemical studies of rat viruses.

The standard potential of the silver-silver bromide electrode and ion solvation in t-butyl alcohol + water mixtures at 298.15 K

E.m.f. measurements of the cell ���������������������� Pt|H2|HBr(m), ButOH(X), water|AgBr|Ag have been made at 298.15 K for solvent compositions X = 10, 20, 30, 40, 50 and 70% (w/w) of t-butyl alcohol. These have been used to evaluate the standard potential of the silver-silver bromide electrode and the free energy of transfer, ΔG�t, of the acid from water to the respective solvent media. These ΔG�t values, along with those for hydrochloric acid, are briefly discussed in relation to ion solvation. ��� Mean ionic activity coefficients of hydrobromic acid in the various solvents have also been calculated.

Activity coefficients of potassium perrhenate in aqueous mixtures with KCl, NaCl and KI at 298.15 K

The solubilities of potassium perrhenate in aqueous NaCl, KCl and KI solutions are reported. The solubility activity product for this electrolyte was determined using extrapolation functions involving three different mean ionic activity coefficient expressions. Mean ionic activity coefficients have been computed for potassium perrhenate in dilute aqueous solutions and there is no justification for considering ion association1,2 in these solutions.

Studies of folic acid compounds in nature. 3. Folic acid compounds in cabbage

The folate pattern in cabbage was studied by chromatography on Sephadex G-25 and DEAE-cellulose columns associated with markers of high specific radioactivity and with differential microbiological assay. More than 90% of cabbage folate is polyglutamates containing more than five glutamic acid residues, mainly as the 5-methyl derivatives. The distribution is as follows: 52% of total cabbage folate is 5-CH3-H4PteGlu7, 32% is 5-CH3-H4PteGluc6, 7% is 5-CH3-H4PteGlu8, 4% is 5-CHO-H4PteGlu7, and the rest is 5-CH3-H4PteGlu3–5.