Showing papers on "In vivo published in 1991"

Generation and analysis of interleukin-4 deficient mice.

Abstract: Interleukin-4 (IL-4) promotes the growth and differentiation of many hematopoietic cells in vitro; in particular, it directs the immunoglobulin (Ig) class switch to IgG1 and IgE. Mice homozygous for a mutation that inactivates the IL-4 gene were generated to test the requirement for IL-4 in vivo. In the mutant mice T and B cell development was normal, but the serum levels of IgG1 and IgE were strongly reduced. The IgG1 dominance in a T cell-dependent immune response was lost, and IgE was not detectable upon nematode infection. Thus, some but not all of the in vitro properties of IL-4 are critical for the physiology of the immune system in vivo.

Thalidomide selectively inhibits tumor necrosis factor alpha production by stimulated human monocytes.

Abstract: Thalidomide selectively inhibits the production of human monocyte tumor necrosis factor alpha (TNF-alpha) when these cells are triggered with lipopolysaccharide and other agonists in culture. 40% inhibition occurs at the clinically achievable dose of the drug of 1 micrograms/ml. In contrast, the amount of total protein and individual proteins labeled with [35S]methionine and expressed on SDS-PAGE are not influenced. The amounts of interleukin 1 beta (IL-1 beta), IL-6, and granulocyte/macrophage colony-stimulating factor produced by monocytes remain unaltered. The selectivity of this drug may be useful in determining the role of TNF-alpha in vivo and modulating its toxic effects in a clinical setting.

Adenovirus-mediated transfer of a recombinant alpha 1-antitrypsin gene to the lung epithelium in vivo

Abstract: The respiratory epithelium is a potential site for somatic gene therapy for the common hereditary disorders alpha 1-antitrypsin (alpha 1AT) deficiency and cystic fibrosis. A replication-deficient adenoviral vector (Ad-alpha 1AT) containing an adenovirus major late promoter and a recombinant human alpha 1AT gene was used to infect epithelial cells of the cotton rat respiratory tract in vitro and in vivo. Freshly isolated tracheobronchial epithelial cells infected with Ad-alpha 1AT contained human alpha 1AT messenger RNA transcripts and synthesized and secreted human alpha 1AT. After in vivo intratracheal administration of Ad-alpha 1AT to these rats, human alpha 1AT messenger RNA was observed in the respiratory epithelium, human alpha 1AT was synthesized and secreted by lung tissue, and human alpha 1AT was detected in the epithelial lining fluid for at least 1 week.

Segregation of atrial-specific and inducible expression of an atrial natriuretic factor transgene in an in vivo murine model of cardiac hypertrophy

Abstract: To study the mechanisms that activate expression of the atrial natriuretic factor (ANF) gene during pressure-induced hypertrophy, we have developed and characterized an in vivo murine model of myocardial cell hypertrophy. We employed microsurgical techniques to produce a stable 35- to 45-mmHg pressure gradient across the thoracic aorta of the mouse that is associated with rapid and transient expression of an immediate-early gene program (c-fos/c-jun/junB/Egr-1/nur-77), an increase in heart weight/body weight ratio, and up-regulation of the endogenous ANF gene. These responses that are identical to those in cultured cell and other in vivo models of hypertrophy. To determine whether tissue-specific and inducible expression of the ANF gene can be segregated, we used a transgenic mouse line in which 500 base pairs of the human ANF promoter region directs atrial-specific expression of the simian virus 40 large tumor antigen (T antigen), with no detectable expression in the ventricles. Thoracic aortic banding of these mice led to a 20-fold increase in the endogenous ANF mRNA in the ventricle but no detectable expression of the T-antigen marker gene. This result provides evidence that atrial-specific and inducible expression of the ANF gene can be segregated, suggesting that a distinct set of regulatory cis sequences may mediate the up-regulation of the ANF gene during in vivo pressure overload hypertrophy. This murine model demonstrates the utility of microsurgical techniques to study in vivo cardiac physiology in transgenic mice and should allow the application of genetic approaches to identify the mechanisms that activate ventricular expression of the ANF gene during in vivo hypertrophy.

Preparation of modified tubulins

Abstract: Publisher Summary This chapter presents a collection of the various different ways by which tubulins are modified to generate probes for investigating microtubule (MT) dynamics in vitro and in vivo . Labeling with biotin and various fluorochromes is described, as well as the preparation of N-ethylmaleimide tubulin, which has been used to block minus-end growth in vitro . The use of GTP analogs to prepare stable labeled microtubules has proved very useful in a number of different experiments. The tubulin used in the presented methods was prepared from bovine brain by two cycles of temperature-dependent polymerization, followed by phosphocellulose chromatography. The cycling procedure described in the chapter selects active subunits and removes free nucleotide. This produces a tubulin preparation suitable for use in in vitro assays. The standard biotin-labeled tubulin preparation has been used to determine sites of microtubule elongation in vivo and in vitro . It is difficult to quantitate the stoichiometry of biotin labeling on a routine basis, but early work using radioactive N-hydroxysuccinimide (NHS)-biotin gave a labeling stochiometry of one to three biotins/tubulin dimer. The final yield of twice cycled biotin-tubulin is about 10% of the starting protein. Tetramethylrhodamine-labeled tubulin has been used to follow microtubules in living cells and it is also used for marking microtubules in real-time in vitro assays.

Lactate rise detected by 1H NMR in human visual cortex during physiologic stimulation.

Abstract: Brain lactate concentration is usually assumed to be stable except when pathologic conditions cause a mismatch between glycolysis and respiration. Using newly developed 1H NMR spectroscopic techniques that allow measurement of lactate in vivo, we detected lactate elevations of 0.3-0.9 mM in human visual cortex during physiologic photic stimulation. The maximum rise appeared in the first few minutes; thereafter lactate concentration declined while stimulation continued. The results are consistent with a transient excess of glycolysis over respiration in the visual cortex, occurring as a normal response to stimulation in the physiologic range.

Design and in vitro studies of a needle-type glucose sensor for subcutaneous monitoring.

Abstract: A new miniaturized glucose oxidase based needle-type glucose microsensor has been developed for subcutaneous glucose monitoring. The sensor is equivalent in shape and size to a 26-guage needle (0.45-mm o.d.) and can be implanted with ease without any incision. The novel configuration greatly facilitates the deposition of enzyme and polymer films so that sensors with characteristics suitable for in vivo use (upper limit of linear range greater than 15 mM, response time less than 5 min, and sensitivity yielding a 5:1 signal-to-background ratio at normal basal glucose levels) can be prepared in high yield (greater than 60%). The sensor response is largely independent of oxygen tension in the normal physiological range. It also exhibits good selectivity against common interferences except for the exogenous drug acetaminophen.

1,25-dihydroxyvitamin D3 prevents the in vivo induction of murine experimental autoimmune encephalomyelitis.

Abstract: The hormone, 1,25-dihydroxyvitamin D3 (1,25-[OH]2-D3), inhibits lymphocyte activation in vitro. We studied the ability of the vitamin D metabolite to interfere in vivo with a primary T cell-mediated model of autoimmunity, murine experimental autoimmune encephalomyelitis (EAE). Within 2 wk of antigenic challenge, immunized animals will develop acute paralysis with central nervous tissue inflammation. If mice survive, a rise in antibody titer develops within a month. The administration of 0.1 microgram 1,25-(OH)2-D3 i.p. given every other day for 15 d, starting 3 d before immunization, significantly prevented the development of EAE. The rise in antibody titer to myelin basic protein was also abrogated. Histopathologic lesions of EAE were inhibited by treatment with the sterol. These results suggest a potent immunosuppressive role for 1,25-(OH)2-D3 in vivo in the modulation of a cell-mediated model of autoimmunity.

Control of embryonic motoneuron survival in vivo by ciliary neurotrophic factor.

Abstract: During development of the nervous system, neurons in many regions are overproduced by proliferation, after which the excess cells are eliminated by cell death The survival of only a proportion of neurons during normal development is thought to be regulated by the limited availability of neurotrophic agents One such putative trophic agent is ciliary neurotrophic factor (CNTF), a polypeptide that promotes the survival of ciliary, sensory, and sympathetic neurons in vitro In contrast to the results of in vitro studies, however, the daily treatment of chick embryos in vivo with purified human recombinant CNTF failed to rescue any of these cell populations from cell death, whereas CNTF did promote the in vivo survival of spinal motoneurons Thus, CNTF may not act as a neurotrophic agent in vivo for those embryonic neurons (especially ciliary neurons) on which it acts in vitro Rather, CNTF may be required for in vivo survival of motoneurons

Intracoronary ultrasound in cardiac transplant recipients. In vivo evidence of "angiographically silent" intimal thickening.

Abstract: BACKGROUND Accelerated coronary atherosclerosis is a major factor limiting allograft longevity in cardiac transplant recipients. Histopathology studies have demonstrated the insensitivity of coronary angiography for detecting early atheromatous disease in this patient population. Intracoronary ultrasound is a new imaging technique that provides characterization of vessel wall morphology. The purpose of this study was to compare in vivo intracoronary ultrasound with angiography in cardiac transplant recipients. METHODS AND RESULTS The left anterior descending coronary artery was studied with intracoronary ultrasound in 80 cardiac transplant recipients at the time of routine screening coronary angiography 2 weeks to 13 years after transplantation. A mean and index of intimal thickening were obtained at four coronary sites. Intimal proliferation was classified as minimal, mild, moderate, or severe according to thickness and degree of vessel circumference involved. Twenty patients were studied within 1 month of transplantation and had no angiographic evidence of coronary disease. An intimal layer was visualized by ultrasound in only 13 of these 20 presumably normal hearts. The 60 patients studied 1 year or more after transplantation all had at least minimal intimal thickening. Twenty-one patients (35%) showed minimal or mild, 17 (28%) moderate, and 21 (35%) severe thickening. Forty-two of these 60 patients had angiographically normal coronary arteries, 21 (50%) of whom had either moderate or severe thickening. All 18 patients with angiographic evidence of coronary disease had moderate or severe intimal thickening, but there was no statistically significant difference in intimal thickness or index when compared with the patients with moderate or severe proliferation and normal angiograms (thickness, 0.53 +/- 0.35 mm versus 0.64 +/- 0.30 mm, p = NS; index, 0.28 +/- 0.10 versus 0.34 +/- 0.10, p = NS). CONCLUSIONS The majority of patients 1 or more years after cardiac transplantation have ultrasound evidence of intimal thickening not apparent by angiography. Intracoronary ultrasound offers early detection and quantitation of transplant coronary disease and provides characterization of vessel wall morphology, which may prove to be a prognostic marker of disease.

5-lipoxygenase inhibitory activity of zileuton.

Abstract: Zileuton [N-(1-benzo[b]thien-2-ylethyl)-N-hydroxyure] inhibited 5-hydroxyeicosatetraenoic acid synthesis by rat basophilic leukemia cell 20,000 x g supernatant and rat polymorphonuclear leukocytes (PMNL) (IC50 = 0.5 and 0.3 microM) respectively. It also inhibited leukotriene (LT)B4 biosynthesis by rat PMNL (IC50 = 0.4 microM), human PMNL (IC50 = 0.4 microM) and human whole blood (IC50 = 0.9 microM). Inhibition of human PMNL LTB4 biosynthesis was removed readily by a simple wash procedure. At concentrations up to 100 microM, the compound produced little or no inhibition of several related enzymes, such as platelet 12-lipoxygenase, soybean and rabbit reticulocyte 15-lipoxygenase and sheep seminal vesicle cyclooxygenase. At p.o. doses from 0.5 to 5 mg/kg in the dog, zileuton produced a rapid and sustained inhibition of ex vivo blood LTB4 biosynthesis which correlated with the pharmacokinetic behavior of the compound. In a similar ex vivo study in the rat, the compound displayed an p.o. ED50 of 2 mg/kg. Zileuton was highly effective in preventing 6-sulfidopeptide LT formation in the rat peritoneal cavity triggered by an antigen-antibody reaction with an ED50 of 3 mg/kg. In experimental models of inflammation, zileuton significantly reduced arachidonic-acid induced mouse ear edema (ED50 = 31 mg/kg) and also attenuated inflammatory cell accumulation in the rat pleural Arthus reaction. The effectiveness of this compound for preventing LT formation in vitro, ex vivo and in vivo suggests its utility for preventing the pathophysiological effects of the LTs and other 5-lipoxygenase products in animals and in humans.

Regulation of murine type 1 plasminogen activator inhibitor gene expression in vivo. Tissue specificity and induction by lipopolysaccharide, tumor necrosis factor-alpha, and transforming growth factor-beta.

Abstract: The regulation of type 1 plasminogen activator inhibitor (PAI-1) gene expression was studied in vivo employing a murine model system. Nuclease protection analysis revealed relatively high concentrations of PAI-1 mRNA in the aorta, adipose tissue, heart, and lungs of untreated CB6 (BalbC X C57B16) mice. Treatment of CB6 mice with LPS, TNF-alpha, or transforming growth factor-beta (TGF-beta) increased the steady-state levels of PAI-1 mRNA within 3 h in all tissues examined. However, the greatest responses to TGF-beta were observed in adipose tissue and the kidney, while LPS and TNF-alpha strongly stimulated PAI-1 gene expression in the liver, kidney, lung, and adrenals. In C3H/HeJ mice, which exhibit defective TNF-alpha release in response to LPS, the response of the PAI-1 gene to LPS was severely attenuated. However, injection of these mice with TNF-alpha increased PAI-1 mRNA in a tissue-specific pattern strikingly similar to that observed in LPS-treated CB6 mice. These results demonstrate that the PAI-1 gene is regulated in a complex and tissue-specific manner in vivo, and suggest a role for TNF-alpha in the response of the PAI-1 gene to sepsis.

Construction, Binding Properties, Metabolism, and Tumor Targeting of a Single-Chain Fv Derived from the Pancarcinoma Monoclonal Antibody CC49

Abstract: CC49 is a "second generation" monoclonal antibody to B72.3, which reacts with the pancarcinoma antigen TAG-72. CC49 has been shown to efficiently target human colon carcinoma xenografts and is currently being evaluated in both diagnostic and therapeutic clinical trials. We describe here the construction and characterization of a recombinant single-chain Fv (sFv) of CC49. The sFv was shown to be a Mr 27,000 homogeneous entity which could be efficiently radiolabeled with 125I or 131I. Comparative direct binding studies and competition radioimmunoassays using CC49 intact IgG, F(ab')2, Fab', and sFv revealed that the monomeric CC49 Fab' and sFv had relative binding affinities 8-fold lower than the dimeric F(ab')2 and intact IgG. Nonetheless, the 131I-labeled sFv was shown to bind biopsies of TAG-72-expressing tumors. Metabolism studies in mice, using radiolabeled CC49 IgG, F(ab')2, Fab', and sFv, demonstrated an extremely rapid plasma and whole body clearance for the sFv. CC49 sFv plasma pharmacokinetic studies in rhesus monkeys also showed a very rapid plasma clearance (T1/2 alpha of 3.9 min and T1/2 beta of 4.2 h). Tumor targeting studies with all four radiolabeled Ig CC49 forms, using the LS-174T human colon carcinoma xenograft model, revealed a much lower percentage injected dose/g tumor binding for the CC49 monomeric sFv and Fab' as compared to the dimeric F(ab')2 and intact IgG. However, tumor:normal tissue ratios (radiolocalization indices) for the sFv were comparable to or greater than those of the other Ig forms. High kidney uptake with 125I-labeled Fab' and F(ab')2 was not seen with 125I-sFv. Gamma scanning studies also showed that 131I-CC49 sFv could efficiently localize tumors. The CC49 sFv may thus have utility in diagnostic and perhaps therapeutic applications for a range of human carcinomas.

Cytotoxic Effects of Resin Components on Cultured Mammalian Fibroblasts

Abstract: The objectives of this study were to determine the cytotoxic concentrations of 11 components of resin composites on monolayers of cultured Balb/c 3T3 fibroblasts, to study the inhibitory effects of these components on DNA synthesis, total protein content, and protein synthesis, and to determine whether effects were reversible when the components were withdrawn from the medium. These data were reported as concentrations which inhibited 10% (ID10) and 50% (ID50) of a particular metabolic process as well as the range of concentrations over which cell metabolism was irreversibly inhibited. For any individual component, the ID50 values for all three metabolic parameters were of the same magnitude. The same was true for the ranges of irreversibility. Ethoxylated Bis-phenol A dimethacrylate (E-BPA) was the most toxic molecule of the group (ID50 being between 1 and 10 mumol/L). The ID50 concentrations for three of the components, including Bis-GMA, UDMA, TEGDMA, and Bis-phenol A, ranged between 10 and 100 mumol/L, while the ID50 values of three components (N,N dihydroxyethyl-p-toluidine, camphoroquinone, and N,N dimethylaminoethyl methacrylate) were above 100 mumol/L. The concentrations to which the cells and tissues are exposed in vivo are not known. This study should help to identify the concentrations of organic composite components which pose clinical cytotoxic hazards.

Models of human metastatic colon cancer in nude mice orthotopically constructed by using histologically intact patient specimens.

Abstract: There is an important need for clinically relevant animal models for human cancers. Toward this goal, histologically intact human colon-cancer specimens derived surgically from patients were implanted orthotopically to the colon or cecum of nude mice. We have observed extensive orthotopic growth in 13 of 20 cases of implanted patient colon tumors. These showed various growth patterns with subsequent regional, lymph-node, and liver metastasis, as well as general abdominal carcinomatosis. Thus, models for human colon cancer have been developed that show (i) local growth, (ii) abdominal metastasis, (iii) general abdominal carcinomatosis with extensive peritoneal seeding, (iv) lymph-node metastasis, (v) liver metastasis, and (vi) colonic obstruction. These models permit the passage of the tumors to form large cohorts. They will facilitate research into the biology of colon cancer metastatic capability and the development of new drugs active against metastatic cancer. These models may also predict the clinical course and the in vivo response to drugs of the cancer of individual patients.

Selective transport of an anti-transferrin receptor antibody through the blood-brain barrier in vivo.

Abstract: The brain capillary endothelium, which makes up the blood-brain barrier (BBB) in vivo, expresses high concentrations of transferrin receptor, and recent studies show that an antitransferrin receptor monoclonal antibody may function as a BBB drug transport vector. The present report examines the pharmacokinetics of clearance of radiolabeled antitransferrin receptor monoclonal antibody from the bloodstream in rats in vivo, and also assesses the extent to which brain selectively extracts the antibody from the blood compared to other peripheral organs such as liver, kidney, myocardium, or lung. [125I]Mouse immunoglobulin G2a control antibody was cleared monoexponentially with a half-time of 9.8 +/- 2.3 h. The clearance of the [3H]OX-26 antitransferrin receptor antibody from blood was biexponential with half-times of 2.2 +/- 0.8 min (61 +/- 10% of clearance) and 3.9 +/- 0.2 h (39 +/- 4% of clearance). The OX-26 antibody was rapidly taken up by liver during the first 60 min after injection, but this uptake reached rapid saturation, and hepatic OX-26 content actually declined subsequent to the first hour after injection. In contrast, brain continuously extracted the OX-26 antibody from the bloodstream, and the brain volume of distribution of OX-26 reached a value 18-fold greater than the volume of distribution of the mouse immunoglobulin G2a at 5 h after injection. There was no specific uptake of the OX-26 by myocardium or lung, and minor uptake by kidney was observed that also reached saturation within the first 60 min after injection.(ABSTRACT TRUNCATED AT 250 WORDS)

In vitro and in vivo consequences of VLA-2 expression on rhabdomyosarcoma cells

Abstract: Cloned integrin alpha 2 subunit complementary DNA was expressed on human rhabdomyosarcoma (RD) cells to give a functional VLA-2 (alpha 2 beta 1) adhesion receptor. The VLA-2-positive RDA2 cells not only showed increased adhesion to collagen and laminin in vitro, but also formed substantially more metastatic tumor colonies in nude mice after either intravenous or subcutaneous injection. These results show that a specific adhesion receptor (VLA-2) can markedly enhance both experimental and spontaneous metastasis. In contrast to the metastasis results, there was no difference in either the in vitro growth rate or apparent in vivo tumorigenicity of RD and RDA2 cells.

Recombinant soluble tumor necrosis factor receptor proteins protect mice from lipopolysaccharide-induced lethality.

Abstract: The in vivo efficacy of human recombinant soluble tumor necrosis factor (TNF) receptor protein to prevent and to treat lipopolysaccharide (LPS)-induced lethal toxicity in D-galactosamine-treated mice was investigated. Chimeric proteins of the receptor extracellular domains fused to the hinge region of human IgG3 were expressed in myeloma cells (rsTNFR-h gamma 3). The fusion proteins had a disulfide-bonded dimeric structure. Upon intravenous injection, their serum concentration decreased relatively slowly after an initial phase of rapid elimination. D-galactosamine-sensitized mice were fully protected from the toxic effects of LPS, if the animal were pretreated with rsTNFR-h gamma 3 at 20 micrograms/animal. Partial protection was seen at significantly lower doses and when rsTNFR-h gamma 3 was given up to 3 h after LPS.

Role of cytokines in the differentiation of CD4+ T-cell subsets in vivo.

Abstract: The realization during the past few years that CD4+ T cells (TH cells) can be subdivided into distinct subsets on the basis of both function and cytokine expression (Mosmann & Coffman 1987, 1989) has helped clarify a number of outstanding questions in immunology. One such question, for example, is whether B-ceil help and delayed-type hypersensitivity (DTH) are mediated by the same type of T cell. Not surprisingly, this revised view of TH cells has raised a new series of questions aboul T cell-mediated regulatory and effector functions. Among the most interesting, and perhaps complex, of the questions are: From what precursors do THI and TH2 cells arise? and: What factors regulate this differentiation process?