The role of macrophages in demyelination.

Experimental allergic encephalomyelitis (EAE) is an autoimmune inflammatory disease of the central nervous system (CNS). In particular in the CsA-induced chronic relapsing form (CREAE), pronounced demyelination occurs, in temporal association with relapses. It is still a matter of discussion which cell type ultimately is responsible for the actual process of demyelination. Macrophages, cytotoxic T lymphocytes and also astrocytes are possible candidates. In this short overview, the role of macrophages in the pathogenesis of EAE is discussed. It is shown that in particular, newly recruited macrophages play a crucial role in the generation of clinical signs. Possible mechanisms by which macrophages are involved in the pathogenesis of demyelinating diseases are presented.


Production of macrophage colony-stimulating factor by astrocytes and brain macrophages.

Morphological hallmarks of inflammatory and degenerative diseases of the brain are hypertrophy of astrocytes and accumulation of macrophages recruited from circulating blood monocytes and/or from resident macrophages, the so-called microglial cells. Recently, production of granulocyte-macrophage colony-stimulating factor (GM-CSF) by astrocytes has been suggested to contribute to the macrophage response. Here we report that in addition to GM-CSF, murine astrocytes also produce macrophage (M)-CSF upon stimulation with tumor necrosis factor alpha, interleukin-1 and lipopolysaccharides. The bioactivity detected in supernatant of astrocytes was characterized using the M-CSF-dependent cell line M-NFS-60 and neutralizing anti-M-CSF antibodies. RNase protection analysis showed M-CSF mRNA already in unstimulated astrocytes without striking up-regulation by the stimuli. Thus, in astrocytes the expression of the M-CSF gene is predominantly regulated at the posttranscriptional level.


Cytokines in neuroinflammatory disease: role of myelin autoreactive T cell production of interferon-gamma.

Many cytokines must be considered as effector and immunoregulatory molecules in neuroinflammatory diseases such as multiple sclerosis (MS) and experimental allergic encephalomyelitis (EAE). We have studied the potential role of interferon-gamma (IFN-gamma) in the pathogenesis of these diseases, since this cytokine has a number of important effects such as macrophage activation, induction of MHC class I and class I antigens, and T cell homing. An immunospot assay that allows enumeration of single cells secreting IFN-gamma after short-term culture in vitro of mononuclear cell suspensions has been used. In EAE, increased numbers of IFN-gamma-secreting cells (IFN-gamma-sc) appear in the central nervous system shortly before onset of clinical signs. Such cells also increased during pharmacologically induced relapse of EAE. In later stages of EAE, memory T cells that produced IFN-gamma in response to presented antigen, recognized multiple regions of the myelin basic protein (MBP), showing that (i) myelin autoreactive T cells have the functional ability to produce this cytokine, (ii) the concept of immunodominance as to autoantigen peptide reactivity is non-absolute and time-dependent. In multiple sclerosis (MS) there are increased numbers of IFN-gamma-sc among the CSF cells. Also, there are increased numbers of memory T cells, strongly enriched to the cerebrospinal fluid, which upon recognition of several myelin antigens and several MBP peptide stretches, produce IFN-gamma. Taken together, the data are consistent with a role for IFN-gamma as a key mediator in inflammatory demyelinating diseases.


Multiple sclerosis and vitamin B12 metabolism.

Multiple sclerosis (MS) is occasionally associated with vitamin B12 deficiency. Recent studies have shown an increased risk of macrocytosis, low serum and/or CSF vitamin B12 levels, raised plasma homocysteine and raised unsaturated R-binder capacity in MS. The aetiology of the vitamin B12 deficiency in MS is often uncertain and a disorder of vitamin B12 binding or transport is suspected. The nature of the association of vitamin B12 deficiency and MS is unclear but is likely to be more than coincidental. There is a remarkable similarity in the epidemiology of MS and pernicious anaemia. Vitamin B12 deficiency should always be looked for in MS. The deficiency may aggravate MS or impair recovery. There is evidence that vitamin B12 is important for myelin synthesis and integrity but further basic studies are required.


The differentiation of glial cell progenitor populations following transplantation into non-repairing central nervous system glial lesions in adult animals.

The non-repairing nature of the locally x-irradiated ethidium bromide (EB)-induced demyelinating white matter lesion has been further validated by showing that injections of two cultures which promote host remyelination of EB lesions in normal tissue do not do so in x-irradiated lesions. The behaviour of an oncogene-immortalized glial cell line and a growth-factor-expanded glial progenitor population have been examined following transplantation into the non-repairing EB lesion. Our studies indicate that the selected glial cell populations were each capable of establishing glial environments around demyelinated axons. Extensive oligodendrocyte remyelination with little astrocytic presence was observed in lesions transplanted with growth-factor-expanded optic nerve progenitors, while less extensive oligodendrocyte remyelination with the establishment of astrocyte-like cells was found in lesions transplanted with ts A58-SV40T immortalized glial cells. Prolonged expansion of both populations resulted in a loss of differentiation to normal glial phenotypes.


Central nervous system demyelination and remyelination in multiple sclerosis and viral models of disease.

The mechanisms of myelin injury and repair were studied in acute multiple sclerosis lesions and in a murine model of demyelination induced by a virus. Injury to oligodendrocytes resulting in degeneration of inner glial loops and inner myelin lamellae (dying-back oligodendrogliopathy) was observed by electron microscopy in brain biopsies of acute demyelinating lesions. Attempts at central nervous system remyelination as manifested by thinly myelinated axons and proliferation of oligodendrocytes were observed at the edge of many acute plaques. To develop therapeutic strategies to inhibit demyelination or promote remyelination, mice infected intracranially with Theiler's virus (a picornavirus) were studied. Experimental manipulation of Theiler's virus-infected mice by treatment during chronic demyelinating disease with immunoglobulins directed at normal spinal cord antigens or with monoclonal antibodies which deplete CD4 or CD8-positive T cells resulted in augmentation of new myelin synthesis. These observations suggest that disturbances in the myelinating function of oligodendrocytes, events not accompanied by death of these cells, may be among the earliest pathological events in multiple sclerosis. Experiments using the Theiler's virus model of demyelination indicate that manipulation of the immune response has the potential to promote central nervous system remyelination and functional recovery in multiple sclerosis.


The effects of high-dose methylprednisolone on gadolinium-enhanced magnetic resonance imaging and cerebrospinal fluid measurements in multiple sclerosis.

Blood-brain barrier (BBB) disruption is probably the first event in the lesion development in multiple sclerosis (MS). This stage can be visualized by gadolinium-enhanced magnetic resonance (MR) imaging of the brain. Serial MR imaging studies have indicated a continuous spectrum of disease activity with waxing and waning of acute lesions, even in clinically stable MS patients. High-dose intravenous methylprednisolone (MP) has a beneficial clinical effect; reduces gadolinium enhancement, indicating improvement of BBB integrity; and, in MS patients, decreases intrathecal immunoglobulin synthesis with reduction of cerebrospinal fluid (CSF) myelin basic protein (MBP). A correlative triad is noted between gadolinium enhancement, clinical improvement, and decrease of CSF MBP following MP treatment, indicating a relationship between restoration of BBB integrity, clinical improvement and decrease of myelin breakdown. It is not clear whether MP interferes primarily with the process of demyelination or reacts non-specifically with its mediators.


Glucocorticoid regulation of eicosanoid production by glial cells under basal and stimulated conditions.

We measured the production of two eicosanoids, prostaglandin E2 and thromboxane-B2, by rat glial cell cultures under basal conditions, following stimulation with phorbol-12-myristate-13-acetate and the bacterial endotoxin lipopolysaccharide, and following treatment with synthetic glucocorticoids. Stimulation of rat glial cells in culture with either phorbol-12-myristate-13-acetate or lipopolysaccharide caused a 1.5-5.0-fold increase in prostaglandin E2 production, but did not affect thromboxane production. Pretreatment of the cultures with dexamethasone markedly inhibited the stimulated production of prostaglandin E2 but had only a modest effect on basal production. Dexamethasone did not affect the activity of the enzyme protein kinase C, a putative regulator of eicosanoid synthesis. Our findings show that glucocorticoids have the potential to modulate central nervous system eicosanoid production particularly under conditions of stimulated production, such as inflammatory and demyelinating disorders. This mechanism may explain, at least in part, the therapeutic benefit of glucocorticoids in patients with multiple sclerosis.


Macrophages and the glucocorticoids.

Macrophages fulfill such functions as (i) housekeeping and scavenging, (ii) protective and defense, and (iii) memory. Glucocorticoids are hormones also used as anti-inflammatory and immuno-suppressive drugs. They act on the many functions of macrophages, mainly by interfering with functions (ii) and (iii). Glucocorticoids interfere with these macrophage functions by modulating the production of inflammatory mediators such as cytokines, phospholipid-derived mediators, proteases, oxygen metabolites. For inducing these effects, glucocorticoids interact with their receptors, transcription factors that recognize specific genomic sequences, glucocorticoid responsive elements (GRE). Glucocorticoids modulate the transcription of genes in association with other transcription factors such as Fos, Jun, CREB, These combinatorial associations--differing according to the differentiation and/or activation state of the cell--may therefore produce a fine-tuning of the induction or repression of genes. These mechanisms shed new light for understanding the complexity of glucocorticoid effects on macrophage function in the inflammatory reaction.


Development and regeneration in the O-2A lineage: studies in vitro and in vivo.

This brief review discusses selected aspects of our studies on the control of division and differentiation of the glial precursor cells which give rise to oligodendrocytes. For more extensive reviews on this topic, the reader is referred to recent reviews by Raff (1989), Richardson et al. (1991), Noble (1991) and Noble et al. (1991).


Modulation of transforming growth factor-beta 1 antiproliferative effects on endothelial cells by cysteine, cystine, and N-acetylcysteine.

Early passaged bovine pulmonary artery endothelial cells exposed to 0.1-2.0 ng/ml transforming growth factor-beta 1 (TGF-beta 1) showed concentration-dependent growth inhibition, as assessed by [3H]thymidine labeling and cell counts, over a 96-h interval. Most of the inhibition of [3H]thymidine labeling measured at 96 h persisted when the medium was replaced with TGF-beta 1-free medium after 24 h, but the inhibition of labeling was prevented by the presence of anti-TGF-beta 1 antibody in the replacement medium. Additions of 2 mM cysteine, 1 mM cystine, or 2 mM N-acetylcysteine at the time of the initial addition of TGF-beta 1 blocked the inhibitory effect of TGF-beta 1 on [3H]-thymidine labeling when this was assessed after 72-96 h, but not at earlier times. Prevention of the inhibitory effect on cellular proliferation produced by cysteine, cystine and N-acetylcysteine was associated with elevation of cellular glutathione that was present at 48-96 h. There was no evidence for direct inactivation of TGF-beta 1 by the thiol-amino acids. Conditioned medium from TGF-beta 1-treated endothelial cells inhibited proliferation of mink lung carcinoma (CCL64) cells, supporting a previously reported concept of autocrine production of TGF-beta 1 by the endothelial cells. The inhibitory action of the conditioned medium was partially prevented when 1 mM cysteine was added during conditioning. Thus, TGF-beta 1 treatment of endothelial cells appears to set off autocrine production by these cells of TGF-beta 1 that perpetuates the inhibition of cellular proliferation. Replenishment of cellular glutathione with thiol-amino acids counteracts the growth-inhibitory effect of TGF-beta 1 through a currently undefined mechanism.


Paradoxical withdrawal of reflex vasoconstriction as a cause of hemodialysis-induced hypotension.

Acute hypotension is an important complication of hemodialysis, but the underlying mechanisms remain poorly understood. Because hemorrhage-induced hypovolemia can trigger a sudden decrease in sympathetic activity resulting in bradycardia and vasodilation, we hypothesized that hemodialysis-induced hypovolemia also can trigger the same type of vasodepressor reaction, which would exacerbate the volume-dependent fall in blood pressure. We therefore measured blood pressure, vascular resistance, and sympathetic nerve activity (intraneural microelectrodes) during sessions of maintenance hemodialysis in 7 patients with and 16 patients without a history of hemodialysis-induced hypotension. During hemodialysis, blood pressure at first remained unchanged as calf resistance increased in both hypotension-resistant (from 37 +/- 4 to 49 +/- 5 U, P < 0.05) and hypotension-prone (from 42 +/- 6 to 66 +/- 12 U, P < 0.05) patients; sympathetic activity increased comparably in the subset of patients in whom it could be measured. With continued hemodialysis, calf resistance and sympathetic activity increased further in the hypotension-resistant patients, but in the hypotension-prone patients the precipitous decrease in blood pressure was accompanied by decreases in sympathetic activity, vascular resistance, and heart rate as well as symptoms of vasodepressor syncope. On an interdialysis day, both groups of patients increased vascular resistance normally during unloading of cardiopulmonary baroreceptors with lower body negative pressure and increased heart rate normally during unloading of arterial baroreceptors with infusion of nitroprusside. These findings indicate that in a group of hemodialysis patients without diabetes or other conditions known to impair autonomic reflexes, hemodialysis-induced hypotension is not caused by chronic uremic impairment in arterial or cardiopulmonary baroreflexes but rather by acute, paradoxical withdrawal of sympathetic vasoconstrictor drive producing vasodepressor syncope.


Sporadic hypertrophic cardiomyopathy due to de novo myosin mutations.

Hypertrophic cardiomyopathy occurs as an autosomal dominant familial disorder or as a sporadic disease without familial involvement. While missense mutations in the beta cardiac myosin heavy chain (MHC) gene account for approximately half of all cases of familial hypertrophic cardiomyopathy, the molecular causes of sporadic hypertrophic cardiomyopathy are unknown. To determine whether beta cardiac MHC mutations are also associated with sporadic disease, we screened this gene in seven individuals with sporadic hypertrophic cardiomyopathy. Mutations in the beta cardiac MHC genes were identified in two probands with sporadic disease. In that their parents were neither clinically nor genetically affected, we conclude that mutations in each proband arose de novo. Transmission of the mutation and disease to an offspring occurred in one pedigree, predicting that these are germline mutations. The demonstration of hypertrophic cardiomyopathy arising within a pedigree coincident with the appearance of a de novo mutation provides compelling genetic evidence that beta cardiac MHC mutations cause this disease. We suggest that de novo mutations account for some instances of sporadic hypertrophic cardiomyopathy and that these mutations can be transmitted to children. The clinical benefits of defining mutations responsible for familial hypertrophic cardiomyopathy should also be available to some patients with sporadic disease.


Regulation of lipoprotein lipase in the diabetic rat.

Diabetes mellitus is associated with a reduction of lipoprotein lipase (LPL) activity and development of hypertriglyceridemia. In the current experiments the mechanisms involved in the regulation of LPL have been examined in control rats, streptozocin-induced diabetic rats, and diabetic rats treated chronically or with a single injection of insulin. Diabetes decreased adipose tissue LPL activity partially by decreasing immunoreactive LPL protein and the steady-state levels of LPL mRNA, but primarily by reducing the catalytic activity of LPL. Both chronic and acute insulin increased adipose tissue LPL activity by correcting the defect in the catalytic activity of LPL and increasing immunoreactive LPL protein; however, only chronic insulin restored LPL mRNA levels to normal. In the heart, LPL activity tended to be elevated with diabetes in parallel to an increase in immunoreactive LPL protein even though levels of LPL mRNA declined. Both chronic and acute insulin normalized LPL activity and immunoreactive LPL protein, while only chronic insulin corrected the levels of LPL mRNA. No changes in the catalytic activity of LPL in heart were detected among the groups. Thus, diabetes and insulin treatment regulate LPL expression pretranslationally, translationally, and post-translationally, with tissue-specific differences apparent in the mechanisms involved.


Glutaric acidemia type II. Heterogeneity in beta-oxidation flux, polypeptide synthesis, and complementary DNA mutations in the alpha subunit of electron transfer flavoprotein in eight patients.

We studied metabolic, polypeptide and genetic variation in eight glutaric acidemia type II (GA II) patients with electron transfer flavoprotein (ETF) deficiency. As measured by 3H-fatty acid oxidations in fibroblasts, beta-oxidation pathway flux correlated well with clinical phenotypes. In six patients with severe neonatal onset GA II, oxidation of [9,10(n)-3H]-palmitate ranged from 2% to 22% of control and of [9,10(n)-3H]myristate, from 2% to 26% of control. Of two patients with late onset GA II, one had intermediate residual activities with these substrates and the other normal activities. Radiolabeling and immunoprecipitation studies revealed that three of the six neonatal onset GA II patients had greatly diminished or absent alpha- and beta-ETF subunits, consistent with a failure to assemble a stable heterodimer. Another neonatal onset patient showed normal synthesis of beta-ETF but decreased synthesis of alpha-ETF. Two neonatal onset and two late onset GA II patients showed normal synthesis of both subunits. Analysis of the pre-alpha-ETF coding sequence revealed seven different mutations in the six patients with neonatal onset GA II. The most common mutation was a methionine for threonine substitution at codon 266 found in four unrelated patients, while all the other mutations were seen in single patients. No mutations were detected in the two patients with late onset GA II.


Homozygous 4.1(-) hereditary elliptocytosis associated with a point mutation in the downstream initiation codon of protein 4.1 gene.

We studied a 43 yr-old Spanish patient with homozygous 4.1(-) hereditary elliptocytosis. Any form of protein 4.1 was missing in the red cells. Spectrin and actin were slightly, yet significantly, diminished. Alterations appeared at the level of proteins 4.5 and 4.9. Glycophorin C was sharply reduced. The abnormal allele was associated with the -++-- haplotype (Pvu II, Bgl II, Bgl II, Pvu II, Pvu II). mRNA 4.1(-) had an apparently normal size but was diminished by about two-thirds. Because the abnormal phenotype pertained to the red cell, we sequenced the 4.1 cDNA regions that appear critical to this cell type. The ultimate change turned out to be a point mutation of the downstream translation initiation codon (AUG-->AGG). No disorders in other cell types could be related with certainty to the present 4.1(-) HE allele.


Neuroendocrine mechanism of onset of puberty. Sequential reduction in activity of inhibitory and facilitatory N-methyl-D-aspartate receptors.

In humans and in several animal species, puberty results from changes in pulsatile gonadotropin-releasing hormone (GnRH) secretion in the hypothalamus. In particular, the frequency of pulsatile GnRH secretion increases at the onset of puberty, as can be shown by using hypothalamic explants of male rats of 15 and 25 d. Previous observations from us and others suggested that the initiation of puberty could involve a facilitatory effect of excitatory amino acids mediated through N-methyl-D-aspartate (NMDA) receptors. We found that GnRH secretion could be activated through NMDA receptors only around the time of onset of puberty (25 d). The aim of this study was to clarify why this activation did not occur earlier (at 15 d) and could no longer be observed by the end of puberty (at 50 d). We studied GnRH secretion in the presence of MK-801, a noncompetitive antagonist of NMDA receptors or AP-5, a competitive antagonist. We showed that, in the hypothalamus of immature male rats (15 d), a highly potent inhibitory control of pulsatile GnRH secretion in vitro was mediated through NMDA receptors. These data were confirmed in vivo because administration of the antagonist MK-801 (0.001 mg/kg) to immature male rats resulted in early pubertal development. Onset of puberty (25 d) was characterized by the disappearance of that NMDA receptor-mediated inhibition, thus unmasking a facilitatory effect also mediated through NMDA receptors. During puberty, there was a reduction in activity of this facilitatory control which was no longer opposed by its inhibitory counterpart. We conclude that a sequential reduction in activity of inhibitory and facilitatory NMDA receptors provides a developmental basis for the neuroendocrine mechanism of onset of puberty.


Blood volume and body fluid compartments in lambs with aortopulmonary left-to-right shunts.

A left-to-right shunt is accompanied by an increased plasma and blood volume. Since this is likely realized through renin/aldosterone-mediated salt and water retention, other body fluid compartments may be changed too. Therefore, we studied blood volume and body fluid compartments by a single-injection, triple-indicator dilution technique in nine 8-wk-old lambs with an aortopulmonary left-to-right shunt (55 +/- 3% of left ventricular output; mean +/- SEM) and in 11 control lambs, 2.5 wk after surgery. Systemic blood flow was maintained at the same level as in control lambs, but the aortic pressure of the shunt lambs was lower. Blood volume in shunt lambs was larger than in control lambs (110 +/- 6 vs. 84 +/- 7 ml/kg, P < 0.001) through an increase in plasma volume, which correlated significantly with the magnitude of the left-to-right shunt (r = 0.81, P < 0.01). Red blood cell volume was equal to that of control lambs. Evidence was obtained that the increase in plasma volume was induced by a transient increase in renin (8.0 +/- 2.2 vs. 1.6 +/- 0.2 nmol.l-1.h-1; P < 0.02) and aldosterone (0.51 +/- 0.14 vs. 0.24 +/- 0.09 nmol/liter) concentrations. Interstitial water volume, however, was not significantly different from that in control lambs. The amount of intravascular protein was significantly higher than in control lambs (5.0 +/- 0.3 vs. 3.5 +/- 0.2 g/kg body mass, P < 0.001). There were no significant differences in intracellular and total body water volumes between the two groups. We conclude that the increased amount of intravascular protein confines the fluid retained by the kidneys to the vascular compartment.


Importance of peripheral insulin levels for insulin-induced suppression of glucose production in depancreatized dogs.

It is generally believed that glucose production (GP) cannot be adequately suppressed in insulin-treated diabetes because the portal-peripheral insulin gradient is absent. To determine whether suppression of GP in diabetes depends on portal insulin levels, we performed 3-h glucose and specific activity clamps in moderately hyperglycemic (10 mM) depancreatized dogs, using three protocols: (a) 54 pmol.kg-1 bolus + 5.4 pmol.kg-1.min-1 portal insulin infusion (n = 7; peripheral insulin = 170 +/- 51 pM); (b) an equimolar peripheral infusion (n = 7; peripheral insulin = 294 +/- 28 pM, P < 0.001); and (c) a half-dose peripheral infusion (n = 7), which gave comparable (157 +/- 13 pM) insulinemia to that seen in protocol 1. Glucose production, use (GU) and cycling (GC) were measured using HPLC-purified 6-[3H]- and 2-[3H]glucose. Consistent with the higher peripheral insulinemia, peripheral infusion was more effective than equimolar portal infusion in increasing GU. Unexpectedly, it was also more potent in suppressing GP (73 +/- 7 vs. 55 +/- 7% suppression between 120 and 180 min, P < 0.001). At matched peripheral insulinemia (protocols 2 and 3), not only stimulation of GU, but also suppression of GP was the same (55 +/- 7 vs. 63 +/- 4%). In the diabetic dogs at 10 mM glucose, GC was threefold higher than normal but failed to decrease with insulin infusion by either route. Glycerol, alanine, FFA, and glucagon levels decreased proportionally to peripheral insulinemia. However, the decrease in glucagon was not significantly greater in protocol 2 than in 1 or 3. When we combined all protocols, we found a correlation between the decrements in glycerol and FFAs and the decrease in GP (r = 0.6, P < 0.01). In conclusion, when suprabasal insulin levels in the physiological postprandial range are provided to moderately hyperglycemic depancreatized dogs, suppression of GP appears to be more dependent on peripheral than portal insulin concentrations and may be mainly mediated by limitation of the flow of precursors and energy substrates for gluconeogenesis and by the suppressive effect of insulin on glucagon secretion. These results suggest that a portal-peripheral insulin gradient might not be necessary to effectively suppress postprandial GP in insulin-treated diabetics.


Mesenchymal cells isolated after acute lung injury manifest an enhanced proliferative phenotype.

After acute lung injury, mesenchymal cells migrate into the alveolar airspace where they proliferate and deposit connective tissue macromolecules. Early in the disease process, inflammatory cell-derived trophic factors modulate these mesenchymal cell functions. However, in those patients who die, even as the inflammatory response abates, the fibroproliferative response continues, resulting in extensive intraalveolar fibrosis. We therefore hypothesized that lung mesenchymal cells obtained from individuals dying with acute alveolar fibrosis would manifest an enhanced proliferative capacity that was independent of persistent exogenous signals. To examine this hypothesis, the in vitro growth properties of mesenchymal cells prepared from patients dying with acute lung injury (n = 3) were analyzed in defined medium and compared with those of mesenchymal cells similarly prepared from patients dying with histologically normal lungs (n = 3). Isolates were characterized as mesenchymal cells by using morphological and immunohistochemical criteria. In accord with the hypothesis, mesenchymal cells isolated from lung-injured patients doubled within 3 d in the complete absence of exogenous peptide growth factors, reaching a saturation density of approximately 15 x 10(3) cells/cm2. As expected, lung mesenchymal cells from normal individuals failed to significantly increase in number. Consistent with this proliferative phenotype, the immediate early cell division cycle genes c-fos and c-jun were constitutively expressed in each cell strain prepared from injured lungs, but not in those from control lungs. The observed proliferative phenotype was stable through the fifth subcultivation of the cells. Despite these proliferative properties, three separate criteria indicated the mesenchymal cells from injured lungs were not transformed: normal karyotype; finite lifespan in vitro (9-10 subcultivations); and inability to disseminate in mice with severe combined immunodeficiency. These data support the hypothesis that mesenchymal cells manifest an enhanced proliferative state after acute lung injury.


Cardiac contractile dysfunction during mild coronary flow reductions is due to an altered calcium-pressure relationship in rat hearts.

Coronary artery stenosis or occlusion results in reduced coronary flow and myocardial contractile depression. At severe flow reductions, increased inorganic phosphate (Pi) and intracellular acidosis clearly play a role in contractile depression. However, during milder flow reductions the mechanism(s) underlying contractile depression are less clear. Previous perfused heart studies demonstrated no change of Pi or pH during mild flow reductions, suggesting that changes of intravascular pressure (garden hose effect) may be the mediator of this contractile depression. Others have reported conflicting results regarding another possible mediator of contractility, the cytosolic free calcium (Cai). To examine the respective roles of Cai, Pi, pH, and vascular pressure in regulating contractility during mild flow reductions, Indo-1 calcium fluorescence and 31P magnetic resonance spectroscopy measurements were performed on Langendorff-perfused rat hearts. Cai and diastolic calcium levels did not change during flow reductions to 50% of control. Pi demonstrated a close relationship with developed pressure and significantly increased from 2.5 +/- 0.3 to 4.2 +/- 0.4 mumol/g dry weight during a 25% flow reduction. pH was unchanged until a 50% flow reduction. Increasing vascular pressure to superphysiological levels resulted in further increases of developed pressure, with no change in Cai. These findings are consistent with the hypothesis that during mild coronary flow reductions, contractile depression is mediated by an altered relationship between Cai and pressure, rather than by decreased Cai. Furthermore, increased Pi and decreased intravascular pressure may be responsible for this altered calcium-pressure relationship during mild coronary flow reductions.


Acquisition and synthesis of folates by obligate intracellular bacteria of the genus Chlamydia.

We undertook studies focused on folate acquisition by Chlamydia trachomatis L2, Chlamydia psittaci 6BC, and C. psittaci francis. Results from in situ studies, using wild-type host cells, confirmed that C. trachomatis L2 and C. psittaci 6BC are sensitive to sulfonamides whereas C. psittaci francis is resistant. In addition C. trachomatis L2 and C. psittaci francis were inhibited by methotrexate in situ whereas C. psittaci 6BC was not. In contrast to C. trachomatis, neither C. psittaci strain was affected by trimethoprim. Surprisingly our results indicate that all three strains are capable of efficient growth in folate-depleted host cells. When growing in folate-depleted cells C. psittaci francis becomes sensitive to sulfonamide. The ability of all three strains to carry out de novo folate synthesis was demonstrated by following the incorporation of exogenous [3H]pABA into intracellular folates and by detecting dihydropteroate synthase activity in reticulate body crude extract. Dihydrofolate reductase activity was also detected in reticulate body extract. In aggregate the results indicate that C. trachomatis L2, C. psittaci francis, and C. psittaci 6BC can all synthesize folates de novo, however, strains differ in their ability to transport preformed folates directly from the host cell.


Inhibition of lung epithelial cell proliferation by hyperoxia. Posttranscriptional regulation of proliferation-related genes.

The alveolar surface of the lung is a major target for oxidant injury. After injury, repair of the alveolar epithelium is dependent on the ability of epithelial type 2 (T2) cells to proliferate. The regulation of T2 cell proliferation and the effect of reactive oxygen (O2) species on this lung cell proliferation have not been well defined. To investigate this process we focused on the regulation of two late cell cycle genes, histone and thymidine kinase, in T2 cells and fibroblasts exposed in vitro to varying periods of hyperoxia (95% O2). Hyperoxia for 24 to 48 h arrested cell proliferation in a SV40T-immortalized T2 cell line we have developed and in primary and SV40T-immortalized lung fibroblasts. Despite the cessation of proliferation, histone and TK mRNA continued to be expressed at high levels; mRNA half-lives were markedly prolonged but neither protein was translated. Thus proliferation arrest induced by hyperoxia was associated with posttranscriptional control of at least two late cell cycle-related genes. This form of proliferation arrest is also seen when primary and SV40T-T2 cells but not fibroblasts are serum deprived, suggesting that T2 cells in vitro may be uniquely sensitive to alterations in their redox state and that these alterations in turn affect translational control of a subset of proliferation-related genes.


New insights on the mechanism(s) of the dominant negative effect of mutant thyroid hormone receptor in generalized resistance to thyroid hormone.

Generalized resistance to thyroid hormone (GRTH) is a syndrome of hyposensitivity to triiodothyronine (T3) that displays autosomal dominant inheritance. The genetic defect commonly lies in the ligand-binding domain of one of the TR beta alleles. Since there are two major thyroid hormone receptor (TR) isoforms, TR alpha and TR beta, it is not known how the mutant receptor mediates a dominant negative effect. Previously, we showed that T3 caused dissociation of TR homodimers and TR alpha/TR beta dimers from several thyroid hormone response elements (TREs). Hence, we used the electrophoretic mobility shift assay to compare the effect of T3 on the DNA binding of mutant TR beta-1 (Mf-1) from a kindred with GRTH with normal TR beta. Mf-1 bound better as a homodimer than TR beta, but dissociated from DNA only at high T3 concentrations. Both receptors heterodimerized with nuclear auxiliary proteins. They also dimerized with TR alpha and with each other. Surprisingly, T3 disrupted the DNA binding of the Mf-1/TR isoform dimers. Thus, mechanisms for the dominant negative effect by mutant TRs likely involve either increased binding to TREs by mutant homodimers that cannot bind T3 (hence cannot dissociate from DNA) and/or the formation of inactive mutant TR/nuclear protein heterodimers.


Induction of thrombospondin 1 by retinoic acid is important during differentiation of neuroblastoma cells.

Neuroblastoma, a malignant neoplasm that arises in the adrenal medulla or sympathetic ganglion, is one of the most common solid tumors of childhood. Reports that neuroblastomas spontaneously mature to form benign ganglioneuromas have prompted investigations into the efficacy of using agents that induce neuronal differentiation in the treatment of this malignancy. Retinoic acid is one agent in particular that has been shown to induce growth inhibition and terminal differentiation of neuroblastoma cell lines in vitro. Using the human neuroblastoma cell line SMH-KCNR, we have investigated the role of the extracellular matrix protein thrombospondin in retinoic acid induced neuroblastoma differentiation. Treatment with retinoic acid results in a rapid induction (within 4 h) of thrombospondin (TSP) message which is independent of intervening protein synthesis and superinducible in the presence of cycloheximide. This suggests that TSP functions as a retinoic acid inducible immediate early response gene. A concomitant increase in both cell associated and soluble forms of TSP protein can be detected within 24 h of retinoic acid treatment. A functional role for TSP in SMH-KCNR differentiation was established in experiments which showed that exposure to anti-TSP monoclonal antibodies delay retinoic acid differentiation for 48 h. At the time the cells overcome the effects of TSP inhibition, laminin production becomes maximal. Treatment of the cells with a combination of anti-TSP and antilaminin antibodies results in complete inhibition of differentiation.


Animal cell mutants represent two complementation groups of peroxisome-defective Zellweger syndrome.

Generalized peroxisome-deficient disorders including cerebro-hepato-renal Zellweger syndrome, neonatal adrenoleukodystrophy, and infantile Refsum disease are autosomal recessive diseases, where catalase-containing particles (peroxisomes) are morphologically absent. We previously isolated two Chinese hamster ovary (CHO) cell mutants (Z24 and Z65) that resemble the fibroblasts from patients with such diseases, in their defective peroxisome assembly (Tsukamoto, T., S. Yokota, and Y. Fujiki. 1990. J. Cell Biol. 110:651-660). Here we report isolation by the P9OH/UV method of a peroxisome-deficient CHO mutant, ZP92, of the third complementation group distinct from those of Z24 and Z65. Peroxisomal membrane ghosts were noted by immunochemical staining in all of the CHO mutants. Complementation analysis by cell fusion of the CHO mutants with cultured fibroblasts from patients with generalized peroxisomal disorders revealed that two CHO mutants (Z24 and ZP92) represent the human complementation groups, E (the same as group 1 in the U.S.) and C (the same as group 4), respectively. These CHO cell mutants are an apparently relevant animal cell model for studies on the molecular bases and primary defects of human peroxisome-deficient diseases.


Identification of rifampin-inducible P450IIIA4 (CYP3A4) in human small bowel enterocytes.

Enzymes within the P450IIIA (CYP3A) subfamily appear to account for significant "first pass" metabolism of some drugs in the intestine. To identify which of the known P450IIIA genes are expressed in intestine, enterocyte RNA was hybridized on Northern blots with synthetic oligonucleotides complementary to hypervariable regions of hepatic P450IIIA4, P450IIIA5, and P450IIIA7 cDNAs. Hybridization was detected only with the P450IIIA4-specific oligonucleotide. The identity of the hybridizing mRNA was confirmed to be P450IIIA4 by direct sequencing of a DNA fragment amplified from enterocyte cDNA by the polymerase chain reaction. To determine if enterocyte P450IIIA4 is inducible, biopsies of small bowel mucosa were obtained from five volunteers before and after they received 7d of treatment with rifampin, a known inducer of P450IIIA4 in liver. Rifampin treatment resulted in a five- or eightfold mean increase (P < 0.05) in the biopsy concentration of P450IIIA4 mRNA when normalized for content of sucrase isomaltase or intestinal fatty acid binding protein mRNAs, respectively. Rifampin also induced P450IIIA immunoreactive protein in enterocytes in each of the subjects, as judged by immunohistochemistry, and resulted in a 10-fold increase in P450IIIA4-specific catalytic activity (erythromycin N-demethylation) in the one patient studied. Our identification of inducible P450IIIA4 in enterocytes may in part account for drug interactions characteristic of P450IIIA4 substrates and suggests a strategy for controlling entry into the body of a major class of xenobiotics.


Mechanism of hypertriglyceridemia in human apolipoprotein (apo) CIII transgenic mice. Diminished very low density lipoprotein fractional catabolic rate associated with increased apo CIII and reduced apo E on the particles.

Hypertriglyceridemia is common in the general population, but its mechanism is largely unknown. In previous work human apo CIII transgenic (HuCIIITg) mice were found to have elevated triglyceride levels. In this report, the mechanism for the hypertriglyceridemia was studied. Two different HuCIIITg mouse lines were used: a low expressor line with serum triglycerides of approximately 280 mg/dl, and a high expressor line with serum triglycerides of approximately 1,000 mg/dl. Elevated triglycerides were mainly in VLDL. VLDL particles were 1.5 times more triglyceride-rich in high expressor mice than in controls. The total amount of apo CIII (human and mouse) per VLDL particle was 2 and 2.5 times the normal amount in low and high expressors, respectively. Mouse apo E was decreased by 35 and 77% in low and high expressor mice, respectively. Under electron microscopy, VLDL particles from low and high expressor mice were found to have a larger mean diameter, 55.2 +/- 16.6 and 58.2 +/- 17.8 nm, respectively, compared with 51.0 +/- 13.4 nm from control mice. In in vivo studies, radiolabeled VLDL fractional catabolic rate (FCR) was reduced in low and high expressor mice to 2.58 and 0.77 pools/h, respectively, compared with 7.67 pools/h in controls, with no significant differences in the VLDL production rates. In an attempt to explain the reduced VLDL FCR in transgenic mice, tissue lipoprotein lipase (LPL) activity was determined in control and high expressor mice and no differences were observed. Also, VLDLs obtained from control and high expressor mice were found to be equally good substrates for purified LPL. Thus excess apo CIII in HuCIIITg mice does not cause reduced VLDL FCR by suppressing the amount of extractable LPL in tissues or making HuCIIITg VLDL a bad substrate for LPL. Tissue uptake of VLDL was studied in hepatoma cell cultures, and VLDL from transgenic mice was found to be taken up much more slowly than control VLDL (P < 0.0001), indicating that HuCIIITg VLDL is not well recognized by lipoprotein receptors. Additional in vivo studies with Triton-treated mice showed increased VLDL triglyceride, but not apo B, production in the HuCIIITg mice compared with controls. Tissue culture studies with primary hepatocytes showed a modest increase in triglyceride, but not apo B or total protein, secretion in high expressor mice compared with controls. In summary, hypertriglyceridemia in HuCIIITg mice appears to result primarily from decreased tissue uptake of triglyceride-rich particles from the circulation, which is most likely due to increased apo CIII and decreased apo E on VLDL particles. the HuCIIITg mouse appears to be a suitable animal model of primary familial hypertriglyceridemia, and these studies suggest a possible mechanism for this common lipoprotein disorder.


Interphase cytogenetics for the detection of the t(11;22)(q24;q12) in small round cell tumors.

Among the small round cell tumors differential diagnosis is particularly difficult for their undifferentiated or primitive character. In this mixed group of tumors, only the primitive neuroectodermal tumors, which include Ewing's sarcoma (ES), show the unique and consistent feature of the (11;22)(q24;q12) translocation, which can therefore be considered a hallmark of these neoplasias. We analyzed four primitive neuroectodermal tumor cell lines, one osteosarcoma cell line, and 11 patients by fluorescent in situ hybridization with cosmid clones 23.2 and 5.8, bracketing the t(11;22) at 11q24. Metaphase spreads from tumor cell lines, and from biopsy specimens of three patients with ES were analyzed. In the remaining eight patients comprising five ES, two small cell osteosarcomas and one chronic osteomyelitis, only nuclei preparations were available for analysis. We detected the t(11;22) in interphase nuclei of the four primitive neuroectodermal tumor cell lines, of three patients in which the karyotype demonstrated the translocation and in five cases of ES in which cytogenetic analysis had not been possible. Two cases of small cell osteosarcoma and one chronic osteomyelitis were also analyzed and were both normal with respect to the t(11;22). By analyzing cell lines and small round cell tumor samples by fluorescent in situ hybridization, we established that interphase cytogenetics is a rapid alternative to chromosomal analysis for the detection of the t(11;22) and represents an invaluable tool for the differential diagnosis of small round cell tumors.


Distinct sites of production and deposition of the putative cell death marker clusterin in the human thymus.

Clusterin is a multifunctional protein endowed with cell-aggregating, complement-inhibitory, and lipid-binding properties. Since several studies have demonstrated highly increased clusterin gene expression in epithelial and nervous tissues regressing as a consequence of tissue involution and apoptotic cell death, clusterin is also considered as a specific marker of dying cells. To determine whether clusterin expression is also upregulated during thymocyte death occurring during the negative selection process we analyzed the cellular distribution of clusterin mRNA and protein by in situ hybridization and immunocytochemistry in the human thymus. We observed that the expression of clusterin mRNA was confined to cells present in the thymic medulla, concentrated mainly around Hassal's bodies. Immunostaining of adjacent sections with antikeratin Ab revealed that cells containing clusterin mRNA were predominantly epithelial. By contrast no clusterin mRNA was found in thymocytes by in situ hybridization and Northern blot analysis of total RNA from purified thymocyte populations. Clusterin protein colocalized with the membrane attack complex of complement and vitronectin in the center of the largest Hassal's bodies, but was not detectable by immunocytochemistry in or at the surface of epithelial cells. Our results demonstrate that clusterin gene expression does not take place in apoptotic thymocytes, and therefore that clusterin synthesis by the dying cell is probably not a prerequisite to its death. However, synthesis of clusterin by medullary epithelial cells may be related to their terminal differentiation, and, furthermore, its presence in Hassal's bodies raises the possibility that the secreted protein is involved in the disposal of cell debris resulting from thymocyte apoptosis.


Regulation of insulin-like growth factor-I and its receptor in rat aorta after balloon denudation. Evidence for local bioactivity.

Local production of growth factors may play a major role in vascular repair after injury. We examined the regulation of insulin-like growth factor-I (IGF-I) and its specific membrane receptor in balloon-denuded rat aorta. Aortic IGF-I mRNA and radioimmunoassayable IGF-I content increased severalfold after balloon denudation with a peak at 7 d after injury. This coincided with a reciprocal 25% decrease in IGF-I receptor mRNA content and a 40% decrease in total 125I-IGF-I binding. Scatchard analysis indicated a single class of binding sites, with a decrease in receptor number at 7 d compared to control and no change in affinity. By in situ hybridization the predominant site of IGF-I expression in the normal and the denuded vessel wall was the medial smooth muscle cell. After denudation there was a relative decrease in IGF-I receptor mRNA in the medial cells as compared to the neointima, suggesting that the site of IGF-I action was predominantly in the medial layer. These data suggest that local expression and action of IGF-I are significant in the promotion of smooth muscle cell proliferation after arterial injury.


Intraglomerular pressure and mesangial stretching stimulate extracellular matrix formation in the rat.

To define the interplay of glomerular hypertension and hypertrophy with mesangial extracellular matrix (ECM) deposition, we examined the effects of glomerular capillary distention and mesangial cell stretching on ECM synthesis. The volume of microdissected rat glomeruli (Vg), perfused ex vivo at increasing flows, was quantified and related to the proximal intraglomerular pressure (PIP). Glomerular compliance, expressed as the slope of the positive linear relationship between PIP and Vg was 7.68 x 10(3) microns 3/mmHg. Total Vg increment (PIP 0-150 mmHg) was 1.162 x 10(6) microns 3 or 61% (n = 13). A 16% increase in Vg was obtained over the PIP range equivalent to the pathophysiological limits of mean transcapillary pressure difference. A similar effect of renal perfusion on Vg was also noted histologically in tissue from kidneys perfused/fixed in vivo. Cultured mesangial cells undergoing cyclic stretching increased their synthesis of protein, total collagen, and key components of ECM (collagen IV, collagen I, laminin, fibronectin). Synthetic rates were stimulated by cell growth and the degree of stretching. These results suggest that capillary expansion and stretching of mesangial cells by glomerular hypertension provokes increased ECM production which is accentuated by cell growth and glomerular hypertrophy. Mesangial expansion and glomerulosclerosis might result from this interplay of mechanical and metabolic forces.


Distinct localization of collagenase and tissue inhibitor of metalloproteinases expression in wound healing associated with ulcerative pyogenic granuloma.

To examine the role of metalloproteinases in tissue remodeling associated with wound healing, we used in situ hybridization to localize the expression of collagenase and tissue inhibitor of metalloproteinases (TIMP) in samples of pyogenic granuloma. Strong hybridization for collagenase mRNA was detected in basal keratinocytes near the advancing edge of all ulcerative lesions, but no collagenase mRNA was seen in samples without ulceration. Distinct from the sites of collagenase expression, TIMP mRNA was detected in stromal cells and in cells surrounding proliferating vessels. No collagenase mRNA was found in the epidermis of healthy skin, although occasional stromal cells contained collagenase or TIMP mRNAs, and TIMP mRNA was detected in hair follicles and sebaceous glands. Our results suggest that basal keratinocytes adjacent to wounded epidermis are critically involved in matrix remodeling, much more so than adjacent or underlying dermal fibroblasts. Furthermore, as several reports have suggested, TIMP may play a role in angiogenesis. Finally, in contrast to findings from other models which indicate that collagenase and TIMP proteins are secreted by the same cells, our data also demonstrate that these proteins can be produced in vivo independently of each other.


Distribution of apolipoprotein(a) in the plasma from patients with lipoprotein lipase deficiency and with type III hyperlipoproteinemia. No evidence for a triglyceride-rich precursor of lipoprotein(a).

Lipoprotein(a) consists of a low-density lipoprotein containing apolipoprotein (apo) B-100 and of the genetically polymorphic apo(a). It is not known where and how lipoprotein(a) is assembled and whether there exists a precursor for lipoprotein(a). We have determined the phenotype, concentration, and distribution of apo(a) in plasma from patients with lipoprotein lipase (LPL) deficiency (type I hyperlipoproteinemia, n = 14), in apo E 2/2 homozygotes with type III hyperlipoproteinemia (n = 12) and in controls (n = 16). In the two genetic conditions, there is grossly impaired catabolic conversion of apo B-100-containing precursor lipoproteins to low-density lipoproteins. Considering apo(a) type, the plasma concentration of apo(a) was normal in type III patients but significantly reduced in LPL deficiency. Despite the defects in the catabolism of other apo B-containing lipoproteins, the distribution of apo(a) was only moderately affected in both metabolic disorders, with 66.7% (type I) and 74.7% (type III) being present as the characteristic lipoprotein(a) in the density range of 1.05-1.125 g/ml (controls 81.6%). The remainder was distributed between the triglyceride-rich lipoproteins (type I 12.4%, type III 8.5%, controls 4.7%) and the lipid-poor bottom fraction (type I 19.3%, type III 15.3%, controls 12.6%). In all conditions most apo(a) (57-88%) dissociated from the triglyceride-rich lipoproteins upon recentrifugation and was recovered as lipoprotein(a). These data suggest that lipoprotein(a) is not generated from a triglyceride-rich precursor. Lipoprotein(a) may be secreted directly into plasma or may be formed by preferential binding of secreted apo(a) to existing low-density lipoprotein.


Natriuretic peptide receptor mRNAs in the rat and human heart.

Functional studies indicate that atrial natriuretic peptide (ANP), a member of the natriuretic peptide family, has direct effects on cardiac muscle cells. However, conventional ligand-binding studies designed to establish the presence of natriuretic peptide-binding sites in the heart have yielded conflicting results. There are discrepancies also between the latter and the receptor distribution predicted from the pattern of the mRNA transcripts localized by in situ hybridization. Here we have employed the technique of cDNA amplification with the polymerase chain reaction to confirm the presence of natriuretic peptide A, B, and C receptor mRNAs in rat and human cardiac tissue. In the rat heart, the distribution of the A and B receptor transcripts appears to be relatively homogeneous; in contrast, the C type mRNA is concentrated principally in the atria, with no difference between the left and right sides of the heart. A and B receptor DNA products were obtained after amplification of left, but not right, ventricular cDNA from the heart of a 16-yr-old male with cystic fibrosis; the yield of C receptor DNA was similar for both ventricles. If these mRNA transcripts are translated into functional receptors in the rat and human heart, ANP and the other natriuretic peptides may have direct effects on cardiac function, including regulation of natriuretic peptide release via a short feedback loop, modulation of contractility of the heart, or activation of cardiac reflexes.


Compartmentation of hexokinase in rat heart. A critical factor for tracer kinetic analysis of myocardial glucose metabolism.

Radiolabeled analogues of 2-deoxyglucose are widely used to trace glucose metabolism in cell cultures, whole organs, and intact animals, although kinetic differences in transport and phosphorylation between these compounds and glucose exist. The present studies were undertaken to determine the effects of insulin stimulation on the phosphorylation of 2-deoxyglucose compared to glucose in the intact, saline-perfused working rat heart. Rates of glucose utilization determined from tritiated glucose differed from rates estimated from the accumulation of [14C]2-deoxyglucose in a nonconstant manner when comparing rates in the absence or presence of physiologic levels of insulin (13 microU/ml). The fraction of monophosphorylated hexoses that was accounted for by [14C]2-deoxyglucose 6-phosphate was dramatically decreased in hearts perfused in the presence of insulin. Additionally, hexokinase activity associated with the mitochondrial fraction of tissue extracts was increased in hearts stimulated by insulin. While this redistribution of hexokinase to the mitochondria did not affect the apparent affinity constant for glucose, hexokinase bound to mitochondria exhibited an 8.5-fold decrease in the affinity for 2-deoxyglucose when compared with hexokinase present in the cytosolic fraction. The findings are consistent with an insulin-mediated preferential uptake and phosphorylation of glucose compared to deoxyglucose. The results also imply that the redistribution of hexokinase and the differential effect of insulin on its affinity for tracer and tracee are responsible for changes in the "lumped constant" (i.e., the correction factor used to equate 2-deoxyglucose to glucose uptake). These changes must be taken into account when regional myocardial glucose metabolism is assessed by the 2-deoxyglucose method.


Alterations in the protein composition of maturing phagosomes.

We investigated the protein composition of J774-E clone macrophage phagosomes isolated at different stages of phagolysosome biogenesis. Phagosomes formed by internalizing antibody-coated Staphylococcus aureus for 3 min followed by chase for 0, 4, 9, or 15 min were isolated by density gradient centrifugation. Enrichment and purity of the phagosome preparations were quantitated by radiolabeled ligand recovery, enzyme markers, and electron microscopy. One-dimensional SDS-PAGE analyses of the isolated phagosomes revealed virtually identical protein compositions. However, Western blot analyses with antibodies directed against selected proteins of known itineraries along the endocytic pathway demonstrated distinct differences in phagosome protein compositions. Accumulating within the maturing phagosome were the 31-kD subunit of the vacuolar proton pump, cathepsin D,beta-glucuronidase, the cation dependent mannose 6-phosphate receptor, and LAMP-1. Decreasing within the maturing phagosome were the FcII receptor, the mannose receptor, and alpha-adaptin. These results indicate that although the macrophage phagosome's total protein composition changes little during phagolysosome formation, the maturing phagosome both receives and eliminates, possibly by protein recycling, specific membrane and sequestered proteins.


Glucose-induced downregulation of angiotensin II and arginine vasopressin receptors in cultured rat aortic vascular smooth muscle cells. Role of protein kinase C.

Early diabetes mellitus is characterized by impaired responses to pressor hormones and pressor receptor downregulation. The present study examined the effect of elevated extracellular glucose concentrations on angiotensin II (AII) and arginine vasopressin (AVP) receptor kinetics in cultured rat vascular smooth muscle cells (VSMC). Scatchard analysis of [3H]AVP and 125I-AII binding to confluent VSMC showed that high glucose concentrations (20 mM) similarly depressed AVP and AII surface receptor Bmax but did not influence receptor Kd. This receptor downregulation was not reproduced by osmotic control media containing either L-glucose or mannitol. Receptor downregulation was maximal at a glucose concentration of 15-20 mM and required 24-48 h for a maximum effect. Normalization of the extracellular glucose concentration allowed complete recovery of AVP and AII binding within 48 h. Receptor downregulation was associated with depressed AVP and AII-stimulated intracellular signaling and cell contraction. High glucose concentrations induced a sustained activation of protein kinase C (PKC) in VSMC, which was prevented by coincubation with H-7. H-7 also markedly attenuated glucose-induced downregulation of AVP and AII receptors on VSMC. This study demonstrates a novel cellular mechanism whereby high extracellular glucose concentrations directly and independently downregulate pressor hormone receptors and their function on vascular tissue via glucose-stimulated PKC activation.


Lipoprotein lipase enhances binding of lipoproteins to heparan sulfate on cell surfaces and extracellular matrix.

Lipoprotein lipase enhances binding at 4 degrees C of human plasma lipoproteins (chylomicrons, VLDL, intermediate density lipoprotein, LDL, and HDL3) to cultured fibroblasts and hepG-2 cells and to extracellular matrix. Heparinase treatment of cells and matrix reduces the lipoprotein lipase enhanced binding by 90-95%. Lipoprotein lipase causes only a minimal effect on the binding of lipoproteins to heparan sulfate deficient mutant Chinese hamster ovary cells while it promotes binding to wild type cells that is abolished after heparinase treatment. With 125I-LDL, lipoprotein lipase also enhances uptake and proteolytic degradation at 37 degrees C by normal human skin fibroblasts but has no effect in heparinase-treated normal cells or in LDL receptor-negative fibroblasts. These observations prove that lipoprotein lipase causes, predominantly, binding of lipoproteins to heparan sulfate at cell surfaces and in extracellular matrix rather than to receptors. This interaction brings the lipoproteins into close proximity with cell surfaces and may promote metabolic events that occur at the cell surface, including facilitated transfer to cellular receptors.


Leukemia inhibitory factor levels are elevated in septic shock and various inflammatory body fluids.

Leukemia inhibitory factor (LIF) has many biological actions which parallel those of IL-1, IL-6 and tumor necrosis factor-alpha, but its role in the pathogenesis of human disease is unknown. A specific radioreceptor competition assay capable of detecting LIF at concentrations above 1 ng/ml (45 pM) was developed. To identify disease states in which LIF might be involved, a cross-sectional survey of serum and body fluids from approximately 1,500 subjects with a variety of diseases was performed using the LIF radioreceptor competition assay. Serum LIF concentrations were transiently elevated (2-200 ng/ml) in six subjects with meningococcal or Gram-negative septic shock, and in a subject with idiopathic fulminant hepatic failure. Moderately elevated LIF concentrations (> 10 ng/ml) were detected in cerebrospinal fluid from subjects with bacterial meningitis, in effusions associated with pneumonia and peritonitis, and in amniotic fluid from a woman with chorioamnionitis. Low LIF concentrations (1-10 ng/ml) were present in synovial fluid from subjects with inflammatory arthritis, amniotic fluid from women in labor, and some reactive, chronic inflammatory and malignant effusions and cyst fluids, but rarely in transudates. These initial findings suggest that LIF might be involved in the pathogenesis of inflammation and septic shock.


An amino acid polymorphism within the RGD binding domain of platelet membrane glycoprotein IIIa is responsible for the formation of the Pena/Penb alloantigen system.

The human Pena/Penb alloantigen system represents a naturally occurring polymorphism of human platelet membrane glycoprotein (GP) IIIa, and has previously been implicated in the onset of two important clinical syndromes, neonatal alloimmune thrombocytopenic purpura and posttransfusion purpura. To investigate the molecular basis of the polymorphism underlying the Pen alloantigen system, we used the polymerase chain reaction to amplify platelet-derived GPIIIa mRNA transcripts. DNA sequence analysis of amplified GPIIIa cDNAs from nucleotides 161 to 1341 (encompassing amino acid residues 22-414) revealed a G526<==>A526 polymorphism that segregated precisely with Pen phenotype in twelve other individuals examined. This nucleotide substitution results in an Arg (CGA) to Gln (CAA) polymorphism at amino acid 143 of GPIIIa. Interestingly, this polymorphic residue is located within the putative RGD binding site (residues 109-171) of GPIIIa. Platelet aggregation patterns of a Penb/b individual, however, were nearly normal in response to all physiological agonists tested, indicating that this polymorphism does not grossly affect integrin function. Short synthetic peptides encompassing residue 143 were unable to mimic either the Pena or Penb antigenic determinants, suggesting that the Pen epitopes are dependent upon proper folding of the polypeptide chain. Finally, we constructed allele-specific recombinant forms of GPIIIa that differed only at amino acid residues 143. Whereas anti-Pena alloantibodies were able to recognize the Arg143 recombinant form of GPIIIa, anti-Penb antibodies were not. Conversely, anti-Penb alloantibodies were reactive only with the Gln143 isoform of the GPIIIa molecule. It thus appears that amino acid 143 of GPIIIa is not only associated with Pen phenotype, but specifically controls the formation and expression of the Pen alloantigenic determinants.


Inhibition of smooth muscle cell proliferation in injured rat arteries. Interaction of heparin with basic fibroblast growth factor.

Heparin inhibits smooth muscle cell (SMC) proliferation after arterial injury by mechanisms that have yet to be defined. Since the initiation of SMC proliferation is mediated by basic fibroblast growth factor (bFGF), we have investigated the possibility that heparin inhibits SMC proliferation by displacing bFGF from the arterial wall. Using a rat carotid artery model of balloon catheter injury, we demonstrate that a bolus injection of heparin depletes the arterial wall of both systemically administered bFGF and of endogenous bFGF. Heparin, however, does not reduce the bFGF content of unmanipulated arteries. Further, a single injection of heparin given at the time of balloon injury reduces SMC proliferation by 55% but has no effect when given 6 h after injury. SMC proliferation induced in a denuded artery by injection of bFGF is inhibited almost completely by a bolus injection of heparin; however, pretreatment with a bolus of heparin does not prevent SMC from responding to a subsequent bolus of bFGF. These experiments suggest that heparin can inhibit SMC proliferation in part by removal of released bFGF from sites of injury.


Low molecular weight iron and the oxygen paradox in isolated rat hearts.

Little is known about changes in the amount of iron in the intracellular low molecular weight pool, which catalyzes the Fenton reactions during reperfusion after ischemia. In this study a new approach is presented to measure low molecular weight iron and it is applied to normal hearts during ischemia and to iron-loaded hearts during anoxia and reoxygenation. The results of this study show that (a) during ischemia in normal hearts a progressive 30-fold increase occurs in low molecular weight iron after 45 min of ischemia, whereas (b) during 45 min of anoxic perfusion the low molecular weight iron does not increase. This means that the reductive release from the storage protein ferritin is greatly enhanced by the acidification that occurs during ischemia. (c) Anoxic perfusion of iron-loaded hearts does increase low molecular weight iron and there is a further increase upon reoxygenation, which is prevented by (+)-cyanidanol-3. Based on these findings it is concluded that oxygen deprivation enhances the susceptibility of rat hearts to oxygen radicals by increasing the amount of catalytic, ferrous iron in the low molecular weight pool.


Role of transforming growth factor-beta in maintenance of function of cultured neonatal cardiac myocytes. Autocrine action and reversal of damaging effects of interleukin-1.

The three isoforms of transforming growth factor-beta (TGF-beta) have previously been implicated in embryonic development of the heart as well as in repair of myocardial damage after ischemia/reperfusion injury. TGF-beta 1 has also been localized intracellularly to both mitochondria and contractile filaments of cardiac myocytes, although its role in these structures has not been defined. We now report that exogenous TGF-beta stabilizes the beating rate of neonatal rat cardiac myocytes cultured on fibroblast matrix, and sustains their spontaneous rhythmic beating in serum-free medium. Moreover, using blocking antibodies to TGF-beta, we show that endogenous TGF-beta secreted by these myocytes acts in an autocrine fashion to maintain their beating rate. In contrast, IL-1 beta, an inflammatory mediator secreted by immune cells during myocardial injury, inhibits the beating of cardiac myocytes, and TGF-beta can overcome this inhibition. The antagonistic effects of TGF-beta and IL-1 were not observed when the myocytes were cultured on gelatin, as compared to native fibroblast matrix. The data indicate that TGF-beta is an important regulator of contractile function of the heart and have significant implications for understanding cardiac physiology in health and disease.


Enhancement of fibrinolysis in vitro by ultrasound.

The effect of ultrasound on the rate of fibrinolysis has been investigated using an in vitro system. Plasma or blood clots containing a trace label of 125I fibrin were suspended in plasma containing plasminogen activator and intermittently exposed to continuous wave 1-MHz ultrasound at intensities up to 8 W/cm2. Plasma clot lysis at 1 h with 1 microgram/ml recombinant tissue plasminogen activator (rt-PA) was 12.8 +/- 1.2% without ultrasound and was significantly (P = 0.0001) increased by exposure to ultrasound with greater lysis at 1 W/cm2 (18.0 +/- 1.4%), 2 W/cm2 (19.3 +/- 0.7%), 4 W/cm2 (22.8 +/- 1.8%), and 8 W/cm2 (58.7 +/- 7.1%). Significant increases in lysis were also seen with urokinase at ultrasound intensities of 2 W/cm2 and above. Exposure of clots to ultrasound in the absence of plasminogen activator did not increase lysis. Ultrasound exposure resulted in a marked reduction in the rt-PA concentration required to achieve an equivalent degree of lysis to that seen without ultrasound. For example, 15% lysis occurred in 1 h at 1 microgram/ml rt-PA without ultrasound or with 0.2 microgram/ml with ultrasound, a five-fold reduction in concentration. Ultrasound at 1 W/cm2 and above also potentiated lysis of retracted whole blood clots mediated by rt-PA or urokinase. The maximum temperature increase of plasma clots exposed to 4 W/cm2 ultrasound was only 1.7 degrees C, which could not explain the enhancement of fibrinolysis. Ultrasound exposure did not cause mechanical fragmentation of the clot into sedimentable fragments, nor did it alter the sizes of plasmic derivatives as demonstrated by SDS polyacrylamide gel electrophoresis. We conclude that ultrasound at 1 MHz potentiates enzymatic fibrinolysis by a nonthermal mechanism at energies that can potentially be applied and tolerated in vivo to accelerate therapeutic fibrinolysis.


Immune complex processing in patients with systemic lupus erythematosus. In vivo imaging and clearance studies.

Abnormal processing of immune complexes (IC) may be important in the pathogenesis of systemic lupus erythematosus (SLE). The clearance of large soluble IC (comprising hepatitis B surface antigen (HBsAg)/anti-HBsAg) radiolabeled with 123I was examined in 12 normal subjects and 10 patients with SLE. IC localization was analyzed by static and dynamic gamma-scintigraphy. Initial IC clearance from blood was more rapid in patients (median t1/2 = 2.15 min) than normals (median t1/2 = 5.15 min) due to more rapid uptake in the liver. However, in the SLE group, up to 12% of complexes were released from the liver after 30-50 min. Splenic uptake of immune complexes was reduced in the patients and there was reduced ability to retain IC in this organ. Plasma complement levels and erythrocyte complement receptor type 1 numbers were reduced in the patients, resulting in defective opsonization of IC and reduced red cell binding in vivo. These observations support the hypothesis that IC handling is abnormal in SLE.


Retinoid protection against x-ray-induced chromatid damage in human peripheral blood lymphocytes.

Oral administration of isotretinoin (13-cis retinoic acid) was shown previously (Kraemer, K. H., J. J. DiGiovanna, A. N. Moshell, R. E. Tarone, and G. L. Peck. 1988. N. Engl. J. Med. 318:1633-1637) to reduce the frequency of skin cancers in xeroderma pigmentosum (XP) patients. The mechanism of protection was unclear. In the present study, x-ray-induced chromatid damage in PHA-stimulated blood lymphocytes from five XP patients receiving isotretinoin was approximately half that in blood samples from the same patients before or subsequent to treatment. The x-ray-induced chromatid damage in blood lymphocytes from a normal control was reduced significantly by cocultivation with blood or plasma from an XP patient receiving isotretinoin or by addition of 10(-6) M isotretinoin to cultures 1 h before x-irradiation. A similar reduction in x-ray-induced chromatid damage was reported previously by adding to the culture medium, mannitol, a scavenger of the free hydroxyl radical, or catalase, which decomposes hydrogen peroxide; both of these products are generated during ionizing radiation. The present observations suggest that isotretinoin acts as a scavenger of such radiation products, thereby providing protection against x-ray-induced chromatid damage.


Plasma lipoprotein metabolism in transgenic mice overexpressing apolipoprotein E. Accelerated clearance of lipoproteins containing apolipoprotein B.

We have reported that transgenic mice overexpressing rat apo E shows marked reduction of plasma cholesterol and triglyceride levels due to the disappearance of VLDL and LDL. In this study, we investigated the metabolism of plasma lipoproteins in transgenic mice. After intravenous injection, the rates of clearance of 125I-VLDL and 125I-LDL were 3.0- and 2.4-fold greater in transgenic mice than in controls, respectively. Furthermore, clearance of chylomicron remnants estimated by oral retinyl palmitate-loading test was markedly enhanced in transgenic mice. The hepatic expression of LDL receptors by immunoblot analysis was similar in both groups. These data suggest that elimination of lipoproteins containing apo B was due to enhanced clearance of these lipoproteins enriched with apo E through hepatic LDL receptors. When fed a high cholesterol diet, controls showed twofold elevation of plasma cholesterol levels with marked increases in VLDL and LDL cholesterol on gel filtration chromatography. In contrast, cholesterol-fed transgenic mice showed resistance against these increases. High cholesterol feeding decreased the activity of hepatic LDL receptors and had no effect on enhancement of chylomicron remnant clearance in transgenic mice. Thus, overexpression of apo E facilitates metabolism of lipoproteins containing apo B presumably primarily via the LDL receptor pathway and possibly through an interaction with the chylomicron remnant receptor.


Mutations in the ligand-binding domain of the androgen receptor gene cluster in two regions of the gene.

We have analyzed the nucleotide sequence of the androgen receptor from 22 unrelated subjects with substitution mutations of the hormone-binding domain. Eleven had the phenotype of complete testicular feminization, four had incomplete testicular feminization, and seven had Reifenstein syndrome. The underlying functional defect in cultured skin fibroblasts included individuals with absent, qualitative, or quantitative defects in ligand binding. 19 of the 21 substitution mutations (90%) cluster in two regions that account for approximately 35% of the hormone-binding domain, namely, between amino acids 726 and 772 and between amino acids 826 and 864. The fact that one of these regions is homologous to a region of the human thyroid hormone receptor (hTR-beta) which is a known cluster site for mutations that cause thyroid hormone resistance implies that this localization of mutations is not a coincidence. These regions of the androgen receptor may be of particular importance for the formation and function of the hormone-receptor complex.


Human insulin-like growth factor I receptor function in pituitary cells is suppressed by a dominant negative mutant.

Hybrid receptors were studied in GC rat pituitary cells overexpressing either wild-type 950Tyr (WT) human insulin-like growth factor I (IGF-I) receptors or mutant human IGF-I receptors truncated at position 952 in the beta subunit transmembrane region (952STOP). 125I-IGF-I binding was increased in both 950Tyr (WT) (14-fold) and truncated human IGF-I receptor (952STOP) stable transfectants (50-fold), when compared to untransfected cells that contained endogenous rat IGF-I receptors. Metabolic cell labeling followed by immunoprecipitation with monoclonal alpha and beta subunit-specific antibodies revealed the presence of hybrid rat/truncated human receptors, truncated transfected human receptors, and WT human IGF-I holotetramers. Both mutant and hybrid receptors were degraded slower than 950Tyr (WT) receptors (> 16 h). Despite their markedly increased ligand binding and prolonged receptor half-life, 952STOP transfectants failed to transduce the IGF-I signal to suppress growth hormone (GH). Also, they neither underwent autophosphorylation nor phosphorylated endogenous proteins. The expected suppression of GH by endogenous rat IGF-I receptors was completely abrogated in 952STOP transfectants (P < 0.001 compared to untransfected cells). Mutant 952STOP cells were therefore completely devoid of biological signaling to GH despite the presence of endogenous rat IGF-I receptors. Thus mutant IGF-I receptors block ligand-mediated endogenous rat IGF-I signaling by functioning as a dominant negative forming nonfunctional human/rat hybrid receptors. Defective IGF-I receptors may function therefore as dominant negative phenotypes which suppress normal receptor responses in pituitary cells.


Novel Fc gamma receptor I family gene products in human mononuclear cells.

Unlike the human Fc gamma RII and Fc gamma RIII families, which exhibit considerable diversity at both the nucleic acid and protein levels, the human Fc gamma RI family has only a single recognized product expressed as a 70-kD cell surface receptor with high affinity for monomeric IgG (hFc gamma RIa1). Using both polymerase chain reaction-based amplification and Northern hybridization, we document multiple interferon-gamma-inducible hFc gamma RI RNA transcripts in human mononuclear cells and neutrophils. The sequences of two of these Fc gamma RI related transcripts indicate that they are alternatively spliced products of a second Fc gamma RI family gene, termed Fc gamma RIB. The cDNA derived from the larger of these transcripts, termed hFc gamma RIb1, encodes a surface molecule that is not recognized by Fc gamma RI specific monoclonal antibodies when transfected into COS-7 cells. Unlike the interferon-gamma-inducible hFc gamma RIA gene product, hFc gamma RIb1 does not bind monomeric IgG with high affinity. However, both hFc gamma RIa1 and hFc gamma RIb1 do bind aggregated human IgG. Previously unrecognized diversity within the hFc gamma RI family includes an interferon-gamma-inducible, putative low affinity Fc gamma receptor that may play an important role in the mechanism by which Fc gamma receptors participate in the humoral immune response.


Two distinct mechanisms for bilirubin glucuronide transport by rat bile canalicular membrane vesicles. Demonstration of defective ATP-dependent transport in rats (TR-) with inherited conjugated hyperbilirubinemia.

Bilirubin is conjugated with glucuronic acid in hepatocytes and subsequently secreted in bile. The major conjugate is bilirubin diglucuronide. Using sealed vesicles which are primarily derived from the canalicular (CMV) and sinusoidal (SMV) membrane vesicle domains of the plasma membrane of hepatocytes, we demonstrated that bilirubin glucuronides are transported by CMV by both ATP- and membrane potential-dependent transport systems. In CMV from normal rats, these processes are additive. In CMV from TR- rats, which have an autosomal recessively inherited defect in biliary secretion of nonbile acid organic anions, ATP-dependent transport of bilirubin diglucuronide was absent whereas the membrane potential driven system was retained. Other canalicular ATP-dependent transport systems, which were previously described for organic cations and bile acids, are functionally retained in TR- rats. Our study indicates that bilirubin glucuronides are primarily secreted into the bile canaliculus by an ATP-dependent mechanism which is defective in an animal model of the human Dubin-Johnson syndrome.


Development of concanavalin A-enzyme immunosorbent assay for glycated haptoglobin using polyclonal and monoclonal antibodies.

Two-site lectin-haptoglobin-enzyme immunosorbent assay (L-Hp-ELISA), is described. Haptoglobin binding to Concanavalin A, immobilized to polystyrene microtiter plate, was estimated by anti-haptoglobin polyclonal and monoclonal antibodies conjugated with horse-radish peroxidase. The range of haptoglobin binding to Concanavalin A, measured by the L-Hp-ELISA was 25 to 300 ng/ml using polyclonal, and 50 to 600 ng/ml using monoclonal anti-haptoglobin antibodies, respectively.


Development of radioimmunoassay for TG-51, a new anti-ulcer drug, and its application.

A sensitive and specific radioimmunoassay for a new anti-ulcer drug TG-51 has been developed and applied to the evaluation of its pharmacokinetics in humans. The antiserum was raised in rabbits against an immunogen of N-Acetyl-TG-51 coupled to human serum albumin. The radioactive compound was prepared by acetylating TG-51 with 3H-Acetic anhydride. The separation of free and antibody-bound N-Acetyl-TG-51 was performed by the dextran coated charcoal technique. TG-51 in biological fluids could be quantitatively converted to N-Acetyl-TG-51 prior to radioimmunoassay. This assay system made it possible to ascertain values of 3 ng/ml of TG-51 in plasma using 100 microliters of samples. Results were in good agreement with a high performance liquid chromatography method (HPLC), and the detection limit was raised 25 fold. The accuracy and repoducibility were also satisfactory. By use of this assay method, plasma levels of TG-51 could be determined after a single oral administration of clinical doses of human volunteers.


Rapid assay for immune complex bound antigens from urine of cancer patients.

Concentrated urine from patients with various types of cancer was fractionated by S-500 gel filtration chromatography to yield high molecular weight (mw) immune complexes (IC) and lower mw immunoglobulin (Ig) fractions. Column fractions were assayed for the presence of IgM and IgG by immunoblot probing using anti-human IgM and anti-human IgG alkaline phosphatase conjugates. These results were used to define IC fractions (those from high mw S-500 fractions which were positive for immunoglobulin) and Ig fractions (those from medium mw S-500 fractions which were positive for immunoglobulin). Antigen components of high mw S-500 IC fractions were then determined by immunoblot probe using medium mw S-500 Ig fractions as the antibody probe (i.e. autoantibody). This method for identification of immune complex antigens has the potential to probe for tumor-associated antigens, autoantigens, or foreign antigens from starting material which contains both immune complex and free immunoglobulin.


An enzyme-linked immunosorbent assay (ELISA) for the detection of trypanosomal antigens in goat serum using a monoclonal antibody.

An IgM murine monoclonal antibody (MAb) TEA 1/23.3.4.6 raised against circulating trypanosome antigens was used in a sandwich ELISA to assay trypanosomal antigens in a trypanosome lysate preparation and in sera from goats infected with Trypanosoma brucei evansi. As little as 1.25 ug/ml of trypanosomal antigen could be detected by this assay. Following infection, trypanosomal antigens were first detected in goat serum 24 hours after the intravenous (i/v) or 6 days after the intramuscular (i/m) inoculation of trypanosome parasites. Antigen levels remained detectable during the course of infection. After treatment with diminazene aceturate, antigens dropped to undetectable levels between day 12 to 41, suggesting that this assay offers a promising approach to the diagnosis of African Trypanosomiasis.


A rapid and sensitive heterogeneous immunoelectrochemical assay using disposable electrodes.

In this novel enzyme-tagged immuoelectrochemical assay, disposable carbon felt discs serve both as electrodes and as the heterogeneous solid phase. Antibodies are immobilized on the carbon felt via a diaminoalkane-biotin-avidin-biotin bridge. Alkaline phosphatase is used as a label. Bound antibodies are monitored by following the electro-oxidation of aminophenol, produced enzymatically from p-amino-phenyl phosphate by the immobilized alkaline phosphatase at the electrode surface. A model system designed for determination of mouse IgG concentration yielded a calibration curve ranging from 10 pg/ml to 100 micrograms/ml. This assay can be performed rapidly and a single determination completed within 20 minutes. The system is useful also for rapid quantitation of a small number (approximately 80 organisms per ml) of bacteria.


Monoclonal antibodies to porcine tumor necrosis factor alpha: development of an enzyme-linked immunosorbent assay.

Five hybridomas (4F4, 14H1, 9B4, 6E10, and 8G7) secreting antibodies to porcine tumor necrosis factor alpha (PTNF-alpha) were obtained from one fusion. Four of the 5 monoclonal antibodies (Mab) recognized recombinant PTNF-alpha (rPTNF-alpha) on western blot and were able to neutralize both rPTNF-alpha and native (released by porcine macrophages) PTNF (nPTNF-alpha, only 4F4, 14H1, and 9B4 tested for the neutralization of nPTNF-alpha) in vitro. A sandwich enzyme-linked immunosorbent assay (ELISA) for PTNF-alpha was developed using Mab 4F4 and purified rabbit polyclonal antibodies against PTNF-alpha. The test detected PTNF-alpha concentrations as low as 400 pg/ml and did not cross react with native porcine TNF-beta, recombinant human TNF-alpha, recombinant mouse TNF-beta or native mouse TNF-alpha. The Mabs and the ELISA should be useful for assessing PTNF-alpha levels in swine serum during disease processes and possibly for alleviation of toxic effects of TNF-alpha.


Development of a direct and indirect chemiluminescence immunoassay for the detection of an organophosphorus compound.

The following study describes the development of two immunoassays for the semiquantitative determination of the organophosphorus compound methyl phosphonic acid, p-aminophenyl 1,2,2-trimethyl-propyl diester (MATP). These assays are a direct competitive, labelled-hapten, enzyme immunoassay and a competitive enzyme immunoassay with indirectly labelled antibody, both with luminescence determination of peroxidase. A camera luminometer was used to determine final signal strength. A constant light reaction was reached using luminol (5-amino-2,3-dihydro-1,4-phalazinedione), and by adding coumaric acid as an enhancer. A five minute interval was selected as exposure time. This phototechnical system makes a semiquantitative detection of MATP possible. The detection limits for both assays were at 10(-6)mol/l MATP. With the help of a microtiter luminometer (reader) the detection limit was reduced to 5 x 10(-8) mol/l MATP, by measuring the real intensity of the chemiluminescence signal.


Non-specific immunoglobulin interactions may lead to false-positive results in assays for human anti-mouse monoclonal antibodies (HAMA).

This abstract demonstrates that non-specific immunoglobulin interactions, of the F(ab')2 region and Fc piece of human IgG may lead to false-positive results in patients being monitored for naturally occurring (pre-existing) or induced human anti-mouse monoclonal Ig antibodies (HAMA). Patient sera tested before administration of murine monoclonal antibodies for immunoscintography or immunotherapy showed 'positive' results when screened by specific ELISA for the presence of pre-existing antibodies to murine immunoglobulin. However, only serum from a patient which had previously received murine monoclonal antibody for immunotherapy, was it possible to show specificity by competitive inhibition. Thus, the use of competitive inhibition by specific antigen (mouse Ig isotype/subtype), sera positive for HAMA or pre-existing HAMA can be distinguished from false-positive reactions.


Production and utilisation of antibodies directed against oestrone sulphate using specific hapten synthesis.

Oestrone-3-sulphate (E13S) is an important metabolite of oestrone. Studies in cattle had previously shown that it is synthesised in the gravid uterus by the foetus, but not by the corpus luteum. Progesterone measurement in milk by radioimmunoassay (RIA) is routinely carried out in some laboratories as a pregnancy test for cattle. The major drawback of progesterone measurement in milk, by RIA, as a pregnancy test was the failure to detect the lack of conceptus in those cows where early embryonic death had occurred but the corpus luteum still persisted thereby giving false positive results. We have developed a direct RIA for E13S by raising antibodies to an immunogen prepared from a specific hapten synthesised by an unambiguous chemical synthesis. The sensitivity of the RIA in milk was found to be 0.368 nmol/l. The levels of E13S in non-pregnant cows are undetectable but during a viable pregnancy, the levels are elevated to greater than 0.40 nmol/l by day 100. There was no cross-reactions in the assay with any free oestrogens. The measurement of this metabolite of oestrone promises to provide an accurate marker for the detection of a viable conceptus in cattle.


Technical note: is there a season for iodinating relaxin?

We report a loss of antibody binding in our porcine relaxin radioimmunoassay that has occurred during the coldest periods of the past three winters. We do not know the reason for this seasonal variation but we have eliminated cold deterioration of the iodide used for radioiodination and equipment failures as explanations.


The prediction and control of behavior revisited: a review of the matching law.

Experimental research conducted over the past 3 decades in relation to behavioral allocation and choice, collectively known as matching law research, is analyzed in this paper. The importance of the matching law for areas ranging from experimental to clinical psychology and psychiatry is discussed in relation to empirical findings that bear upon the validity and utility of the matching law for both the prediction and control of human behavior as well as for psychological and scientific inquiry in general.


Attitudes of Arabic psychology students toward behavior modification.

Several American studies have investigated attitudes toward behavior modification. As there are no data on perceptions of this approach in other countries, this study was undertaken to examine such attitudes in Arab countries. The attitudes of 102 undergraduate psychology students at the University of Jordan were assessed. The results showed that behavior modification is favorably received. No significant differences were found between male and female students, or among second, third, and fourth year students. However, significant differences were found between students who had taken a behavior modification course and those who had not.


Skin temperature biofeedback: evaluation of non-clinical children's responses.

The present study evaluated the extent to which children are able to learn to increase skin temperature with biofeedback training. Forty-nine children (ages 7-16) were randomly assigned to either standard biofeedback, novel biofeedback or control groups, which met for 16, 16, and 5 sessions, respectively. Results indicated children in the novel biofeedback group significantly increased their skin temperature as compared with the control group. The biofeedback groups exhibited significant skin temperature control during feedback. Results provide normative data on what to expect from children receiving skin temperature biofeedback.


Behavioral intervention to reduce water intake in the syndrome of psychosis, intermittent hyponatremia, and polydipsia.

We describe a non-intensive behavioral intervention using an A-B design with extended follow-up on an open psychiatric unit to reduce water intake in a 52-year-old man with the syndrome of psychosis, intermittent hyponatremia, and polydipsia. A reinforcement schedule contingent upon weight gain secondary to water intake was employed. Mean diurnal weight gain was 7.1 pounds during a 23-week baseline which dropped to 4.1 pounds following 23 weeks of treatment and at a 1-year follow-up. Estimated fluid consumption dropped from 10 liters to 4 liters daily and incidents of hyponatremia decreased by 62%.


The efficacy of rational emotive therapy in adults: clinical fact or psychometric artifact?

The efficacy of Rational-Emotive Therapy (RET) in reducing maladjustment, while insistently touted by its advocates, has not been unambiguously demonstrated in outcome research. Previous reviews have generally been quite partisan and subjective, and have not reflected available research. The object of the present review was to determine the extent to which RET significantly improved adjustment of adult subjects on different outcome measures in comparison with wait-list, placebo, and other treatment conditions. In 75 outcome reports, RET was effective in only about 25% of comparisons. Its main effect was to reduce scores of self-reported irrationality and dysphoria. Little change was noted in behavioral measures. The few comparisons favoring RET could be attributed to psychometric artifacts rather than to the reduction of irrational beliefs.


Monoclonal antibody JC1: new reagent for studying cell proliferation.

To characterise a newly developed mouse monoclonal antibody JC1 which recognises a nuclear antigen present in proliferating cells in normal tissues and neoplastic lesions, and which is absent in resting cells. The methodology was established using a representative range of frozen sections from normal tissues and from certain tumours which were immunostained with antibodies Ki67 and JC1. The molecular weight of the antigen recognised by JC1 was obtained by western blot analysis and this was compared with that of Ki67. IM-9 cell lysates containing Ki67 derived plasmids were also tested with JC1 antibody. Biochemical investigation indicated that the antigen recognised by JC1 gives two molecular weight bands of 212 and 123 kilodaltons, which is distinct from the well characterised anti-proliferation monoclonal antibody Ki67 (395-345 kilodaltons). In addition recombinant Ki67 protein is not recognised by JC1. Immunohistological reactivity was seen in areas known to contain numerous proliferating cells such as lymphoid germinal centres, splenic white matter, cortical thymocytes and undifferentiated spermatogonia. In tumours many cells from adenocarcinomas, oat cell carcinomas, squamous cell carcinomas of lung, and seminomas were labelled by JC1 with a distribution and proportion similar to that seen with Ki67. In normal tissues the only apparent difference was in testis where JC1 stained a considerably greater number of cells than Ki67. In all cases studied the new antibody showed nuclear reactivity only. JC1 did not show any cytoplasmic crossreactivity with squamous cells as is frequently seen with Ki67. Antibody JC1, which recognises a nuclear antigen present in proliferating cells, should provide a useful adjunct to Ki67 as a marker of proliferation especially in those cases such as squamous cell carcinomas where a Ki67 index cannot be determined.


Demonstration of HIV-1 infected cells in human placenta by in situ hybridisation and immunostaining.

To show the presence of HIV infected cells in the placentas and membranes exposed to HIV during pregnancy, and to trace the possible transmission routes from mother to fetus. Twenty three therapeutic abortions and 11 term placentas were investigated for the presence of HIV antigen by immunostaining with HIV core protein specific antibodies and HIV nucleic acids by in situ hydridisation (ISH) with a 35S-labelled HIV specific RNA probe. HIV antigen as well as HIV RNA positive cells were rarely found in placental tissue and membranes. In therapeutic abortions HIV antigen was shown in 10 out of 23 placentas, HIV RNA in two. HIV antigen was detected in five out of 11 term placentas and HIV RNA in two. Infected cell types comprised syncytiotrophoblasts, Hofbauer cells, amnionic epithelium, chorionic macrophages as well as maternal lymphocytes in the intervillous space and decidua. These data suggest that the transmission routes are: (1) a haematogenous route from the maternal intervillous space to villous stromal cells; (2) from chorion laeve to amnionic fluid and vice versa. Two additional transmission routes are partly suggested by the data: (1) in early gestation by direct extension from basal decidua to budding trophoblastic cells; (2) from the capsular decidua to chorion laeve and chorionic plate, entering the fetal circulation via the small veins.


Cell sizing in chronic lymphoproliferative disorders: an aid to differential diagnosis.

To determine if leucocyte volume distribution analysis (LVDA), obtained using a Coulter Counter Model S Plus IV, can be used to aid differentiation of chronic lymphoproliferative disorder (CLPD) subtypes. Mean lymphocyte volume and lymphocyte distribution width were measured on each patient (n = 90) using a hard copy of an amplified LVDA histogram. The mean lymphocyte volume was taken as the mean of the values on either side of the peak at half maximum height. The lymphocyte distribution width was taken as the range of cell values between the two values used to calibrate the mean lymphocyte volume. A template showing typical histograms from commonly occurring CLPD was also produced on an acetate sheet. This was used to examine the histogram from each new patient to evaluate its usefulness as an alternative to the calculation of mean lymphocyte volume and lymphocyte distribution width. Mean lymphocyte volume and lymphocyte distribution width were significantly higher in B cell lymphocytic leukaemia of mixed cell type (B CLL/PL), B cell non-Hodgkin's lymphoma with peripheral blood spill, hairy cell leukaemia and T cell prolymphocytic leukaemia than in B cell chronic lymphocytic leukaemia (B CLL). The mean lymphocyte volume, but not the lymphocyte distribution width, was also significantly higher in T cell chronic lymphocytic leukaemia than in B CLL. The template gave an immediate preliminary indication of possible subtype(s) of disorder and could be used as an alternative to measurement of mean lymphocyte volume and lymphocyte distribution width. Electronic haematology analysers producing an LVDA provide a useful, cost effective cell sizing analysis which can aid the differentiation of subtypes of CLPD.


ICAM-1 expression in renal disease.

To determine the role of intercellular adhesion molecule-1 (ICAM-1) in immune mediated damage in glomerulonephritis, and whether its expression correlates with disease activity. Fifty three renal biopsy specimens from a range of non-immune renal disease and low grade and high grade glomerulonephritides were stained with ICAM-1. Positivity was assessed in the tubules. Tubular damage and accompanying interstitial inflammation were also noted. The ICAM-1 positivity in damaged and undamaged tubules was correlated with the three groups of renal disease. ICAM-1 positivity in undamaged tubules was observed in glomerulonephritis, and this showed a strong correlation with disease activity. In contrast, ICAM-1 positivity on damaged tubules correlated with evidence of chronic tubular damage, and was seen in a large proportion of cases, regardless of the underlying disease. There was no correlation between ICAM-1 positivity and a local lymphocytic infiltrate. ICAM-1 probably has an important role in the pathogenesis of glomerulonephritis. Its expression may be secondary to cytokines released by cells participating in the glomerular damage. As these cytokines also influence tubule function, tubular ICAM-1 expression may be a marker of the extent of tubular disturbance in glomerulonephritis.