Rapid analysis of gene expression (RAGE) facilitates universal expression profiling

Current techniques for analysis of gene expression either monitor one gene at a time, for example northern hybridization or RT-PCR methods, or are designed for the simultaneous analysis of thousands of genes, for example microarray hybridization or serial analysis of gene expression. To provide a flexible, intermediate scale alternative, a PCR-based method for the rapid analysis of gene expression has been developed which allows expression changes to be determined in either a directed search of known genes, or an undirected survey of unknown genes. A single set of reagents and reaction conditions allows analyses of most genes in any eukaryote. The method is useful for assaying on the order of tens to hundreds of genes in multiple samples. Control experiments indicate reliable detection of changes in gene expression 2-fold and greater, and sensitivity of detection better than 1 in 10 000. Analyses of over 400 genes in a mouse system transgenic for the E2F1 gene have identified several new downstream targets of E2F1, including Brca1 and Cdk7, in addition to several unidentified genes that are upregulated in the transgenic mice. Changes in expression of several genes related to apoptosis suggest a possible potentiation of apoptotic pathways in the transgenic keratinocytes.

Tumor necrosis factor-alpha increases lactoferrin transcytosis through the blood-brain barrier

Lactoferrin (Lf) is an iron-binding protein involved in host defense against infection and severe inflammation, which accumulates in the brain during neurodegenerative disorders. Prior to determining Lf function in pathological brain tissues, we investigated its transport through the blood-brain barrier (BBB) in inflammatory conditions. For this purpose, we used a reconstituted BBB model consisting of the coculture of bovine brain capillary endothelial cells (BBCECs) and astrocytes in the presence of tumor necrosis factor-alpha (TNF-alpha). As TNF-alpha can be either synthesized by brain glial cells or present in circulating blood, BBCECs were exposed to this cytokine at their luminal or abluminal side. We have been able to demonstrate that in the presence of TNF-alpha, whatever the type of exposure, BBCECs were activated and Lf transport through the activated BBCECs was markedly increased. Lf was recovered intact at the abluminal side of the cells, suggesting that increased Lf accumulation may occur in immune-mediated pathophysiology. This process was transient as 20 h later, cells were in a resting state and Lf transendothelial traffic was back to normal. The enhancement of Lf transcytosis seems not to involve the up-regulation of the Lf receptor but rather an increase in the rate of transendothelial transport.

Lactoferrin is synthesized by mouse brain tissue and its expression is enhanced after MPTP treatment

The presence of iron in brain tissue in increased concentrations in Parkinson's disease cases, where it might be responsible for oxidative stress, and the parallel observation that the iron transporter lactoferrin (Lf) was present in increased amounts in surviving neurons, led us to study the synthesis of Lf in a mouse model of Parkinson's disease. In this context, the origin and expression of brain Lf in normal, aged and MPTP (1-methyl-4-phenyl-1, 2,3,6-tetrahydropyridine)-treated mice were investigated. Lf immunostaining was observed mainly on microvessels in the cerebral cortex of the adult mice and to a greater extent in older mice. Lf immunoreactivity was also present in the hippocampus only in the aged mouse brains, associated with structures which seemed to be pyramidal neurons and fibers. After RT-PCR (polymerase chain reaction), Lf transcripts were found in mouse brain tissue whatever the age of the animals studied but the level of their expression was very low. No up-regulation of Lf was detectable during aging. Lf distribution and expression in the MPTP-induced Parkinsonian mouse model were also investigated. A marked depletion of dopamine (DA) occurred in the high dose MPTP-treated mice. The level of Lf expression was found to be markedly increased in the same animals and this up-regulation occurred on the first day after MPTP administration. When the brain was stressed by the neurotoxin MPTP, Lf expression increased in line with antioxidant enzymes such as catalase and gamma-glutamylcysteine synthetase, which may permit the protection of brain tissue from oxidative damage induced by the drug.

Activation of granulocyte-macrophage colony-stimulating factor and interleukin-3 receptor subunits in a multipotential hematopoietic progenitor cell line leads to differential effects on development

Activation of specific cytokine receptors promotes survival and proliferation of hematopoietic progenitor cells but their role in the control of differentiation is unclear. To address this issue, the effects of human interleukin-3 (hIL-3) and human granulocyte-macrophage colony-stimulating factor (hGM-CSF) on hematopoietic development were investigated in hematopoietic progenitor cells. Murine multipotent factor-dependent cell-Paterson (FDCP)-mix cells, which can self-renew or differentiate, were transfected with the genes encoding the unique alpha and/or shared beta(c) human hIL-3 receptor (hIL-3 R) or hGM-CSF receptor (hGM R) subunits by retroviral gene transfer. Selective activation of hIL-3 Ralpha,beta(c) or hGM Ralpha,beta(c) transfects by hIL-3 and hGM-CSF promoted self-renewal and myeloid differentiation, respectively, over a range of cytokine (0.1 to 100 ng/mL) concentrations. These qualitatively distinct developmental outcomes were associated with different patterns of protein tyrosine phosphorylation and, thus, differential signaling pathway activation. The cell lines generated provide a model to investigate molecular events underlying self-renewal and differentiation and indicate that the alpha subunits act in combination with the hbeta(c) to govern developmental decisions. The role of the alpha subunit in conferring specificity was studied by using a chimeric receptor composed of the extracellular hIL-3 Ralpha and intracellular hGM Ralpha subunit domains. This receptor promoted differentiation in response to hIL-3. Thus, the alpha subunit cytosolic domain is an essential component in determining cell fate via specific signaling events.

The acute reversal sign: comparison of medical and non-accidental injury patients

OBJECTIVES

(1) To compare the intracranial computed tomography (CT) appearances of patients admitted with various causes of hypoxic ischaemic encephalopathy. Children with known documented accidental trauma were excluded. (2) To compare our results with those in the published literature.

MATERIALS AND METHODS

Seventy-three patients aged between 1 day and 15 years were admitted with clinical features of brain injury and underwent cranial CT. A retrospective review of their medical records and radiology was undertaken. Clinical and radiological data were collected.

RESULTS

On the basis of the combination of the presenting clinical history, progress, outcome, long term follow up and radiology, two groups of patients were identified. Forty-seven children had been the victims of non-accidental injury (NAI). No child in this group had any associated medical condition or any other medical cause for brain injury. All 47 children demonstrated hypoxic ischaemic encephalopathy and had CT signs of cerebral oedema and 'Reversal Sign'. Intracranial haemorrhage was a highly associated feature. Subdural blood was demonstrated in all 47, acute interhemispheric fissure subdural in 42, intracerebral blood in 16 and intraventricular blood in nine. The remaining 26 children were found to have an identifiable 'medical' cause for brain injury. Acute reversal was demonstrated in 21 of this group. Intracranial haemorrhage was uncommon, found in only five and all five had an underlying predisposition to bleeding. No patient in this group demonstrated subdural blood.

CONCLUSION

Non-accidental injury is strongly associated with the finding on CT of intracranial blood, particularly subdural haematoma and interhemispheric fissure bleeding in the presence of hypoxic ischaemic brain injury. The outlook is extremely poor whatever the underlying cause for hypoxic ischaemic brain injury.

The epidemiology of lip cancer: a review of global incidence and aetiology

Lip cancer (140 ICD-9) is a form of oral cancer that has a distinctive global epidemiology. This review summarises global incidence rates for male and female lip cancer with the aid of cancer atlases. High male lip cancer rates are reported for regions of North America (12.7 per 100 000 per annum), Europe (12.0 per 100 000 per annum) and Oceania (13.5 per 100 000 per annum), while it is virtually unknown in parts of Asia. Factors commonly cited as important in the aetiology of lip cancer include solar radiation, tobacco smoking and viruses. An attempt is made to summarise the evidence for factors that may be important in lip carcinogenesis. While incidence rates are generally stable or falling among males worldwide, they are rising in many female populations. The aetiology of the disease is far from established and much information regarding its pathogenesis is based on anecdotal rather than case-controlled epidemiological evidence. The epidemiology of lip cancer supports the proposal that the lip should be considered as a distinct cancer site, rather than being included with other forms of intraoral cancer.

Receptor-mediated transcytosis of lactoferrin through the blood-brain barrier

Lactoferrin (Lf) is an iron-binding protein involved in host defense against infection and severe inflammation; it accumulates in the brain during neurodegenerative disorders. Before determining Lf function in brain tissue, we investigated its origin and demonstrate here that it crosses the blood-brain barrier. An in vitro model of the blood-brain barrier was used to examine the mechanism of Lf transport to the brain. We report that differentiated bovine brain capillary endothelial cells exhibited specific high (Kd = 37.5 nM; n = 90,000/cell) and low (Kd = 2 microM; n = 900,000 sites/cell) affinity binding sites. Only the latter were present on nondifferentiated cells. The surface-bound Lf was internalized only by the differentiated cell population leading to the conclusion that Lf receptors were acquired during cell differentiation. A specific unidirectional transport then occurred via a receptor-mediated process with no apparent intraendothelial degradation. We further report that iron may cross the bovine brain capillary endothelial cells as a complex with Lf. Finally, we show that the low density lipoprotein receptor-related protein might be involved in this process because its specific antagonist, the receptor-associated protein, inhibits 70% of Lf transport.

Lactoferrin is synthesized by mouse brain tissue and its expression is enhanced after MPTP treatment

The biological role and origin of human lactoferrin (Lf) within the brain in normal and disease processes are as yet uncharted. In this context the origin and expression of brain Lf in normal and MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine)-treated mice were investigated using immunohisto chemistry, PCR amplification and in situ hybridization. Lf immunostaining was observed both on sections of mouse lactating mammary gland, which was used as a positive control, and brains from young, adult and aged mice. Lf immunoreactivity was present in the pituitary gland, the hippocampus and the cortex of mouse brains and to a greater extent in older mice. After reverse transcription, Lf transcripts were also found in these brain sections. Lf distribution and expression in the MPTP-induced parkinsonian mouse model were next investigated. A marked depletion of dopamine and its metabolites: dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA) and 5-hydroxy indole acetic acid (5-HIAA) occurs in the high dose MPTP-treated mice. The level of Lf expression was found to be greatly increased in the same animals but Lf immunoreactivity detected in the same brain region was not found increased in the affected areas.

p210 Bcr-Abl expression in a primitive multipotent haematopoietic cell line models the development of chronic myeloid leukaemia

Chronic myeloid leukaemia (CML) is a clonal disorder of the pluripotent haemopoietic stem cell, the hallmark of which is the constitutively activated Bcr-Abl protein tyrosine kinase. During the initial chronic phase of CML the primitive multipotent leukaemic progenitor cells remain growth factor dependent and are capable of producing terminally differentiated cells. Although the available evidence suggests that Bcr-Abl directly affects signalling pathways involved in controlling the development of primitive haemopoietic progenitors the identification of the specific biological consequences of Bcr-Abl activity in these progenitors has been hampered by the lack of suitable systems modelling CML. By transfecting the multipotent haemopoietic cell line FDCP-Mix with a temperature sensitive mutant of Bcr-Abl we have developed the first working model that mirrors the chronic phase of CML. FDCP-Mix cells expressing Bcr-Abl tyrosine kinase activity remain growth factor dependent and retain their ability to differentiate. Normal neutrophilic cells are formed in response to G-CSF and GM-CSF. In addition, the transfected FDCP-Mix cells grown at the permissive temperature for Bcr-Abl tyrosine kinase activity display enhanced survival and proliferation in low concentrations of growth factor. These findings are consistent with the initial subtle changes seen in CML progenitor cells during the chronic phase and confirm that Bcr-Abl effects are context specific, i.e. they depend on the origin and developmental potential of the transfected cells. This questions the significance of studies in non-haemopoietic and differentiation blocked haemopoietic cells.

Pulpal injury: pathology, diagnosis and periodontal reactions

Diagnosis of pulpal disease can be difficult due to the lack of diagnostic signs and symptoms available to the practitioner. An understanding of the possible underlying pathological processes, combined with an exact assessment of the pain history, and appropriate clinical tests, should aid the practitioner in determining the nature of pulpal inflammation, and differentiating it from dentine sensitivity and cracked teeth. The responses of the pulp to traumatic injury to the periodontal membrane (PDM) require special consideration, particularly with respect to the assessment of pulp vitality, and the determination of cases requiring pulp extirpation in order to avoid inflammatory root resorption. Although the pulp is relatively isolated from the rest of the dentoalveolar complex by a dentine/cementum barrier, it is important to remember that it can communicate with the PDM through apical and lateral foramina, and areas of damaged cementum. Hence, it is a priority to both preserve the integrity of the cemental layer in cases of traumatic injury and periodontal disease, and to prevent the inflammation and resorption associated with periapical lesions by accurate diagnosis of irreversible pulpitis and pulp necrosis, followed by appropriate endodontic debridement procedures.

An activated protein kinase C alpha gives a differentiation signal for hematopoietic progenitor cells and mimicks macrophage colony-stimulating factor-stimulated signaling events

Highly enriched, bipotent, hematopoietic granulocyte macrophage colony-forming cells (GM-CFC) require cytokines for their survival, proliferation, and development. GM-CFC will form neutrophils in the presence of the cytokines stem cell factor and granulocyte colony-stimulating factor, whereas macrophage colony-stimulating factor leads to macrophage formation. Previously, we have shown that the commitment to the macrophage lineage is associated with lipid hydrolysis and translocation of protein kinase C alpha (PKCalpha) to the nucleus. Here we have transfected freshly prepared GM-CFC with a constitutively activated form of PKCalpha, namely PKAC, in which the regulatory domain has been truncated. Greater than 95% of the transfected cells showed over a twofold increase in PKCalpha expression with the protein being located primarily within the nucleus. The expression of PKAC caused macrophage development even in the presence of stimuli that normally promote only neutrophilic development. Thus, M-CSF-stimulated translocation of PKCalpha to the nucleus is a signal associated with macrophage development in primary mammalian hematopoietic progenitor cells, and this signal can be mimicked by ectopic PKAC, which is also expressed in the nucleus.

Ectopic interleukin-5 receptor expression promotes proliferation without development in a multipotent hematopoietic cell line

The interleukin-5 (IL-5) receptor is a heterodimer that consists of an IL-5 specific alpha subunit and a common ssc chain that is shared with the receptors for granulocyte macrophage colony stimulating factor (GM-CSF) and interleukin-3 (IL-3). In contrast to IL-5, which acts mainly as an eosinophil lineage specific factor in vivo, IL-3 and GM-CSF stimulate the survival, proliferation and development of various hematopoietic cell lineages and also multipotent progenitor cells. IL-5 has little effect on the survival or proliferation of the multipotent stem cell line FDCP-Mix A4 but does promote some eosinophil development. To investigate whether the lineage specificity of IL-5 is due to the restricted expression of the IL-5 receptor alpha subunit we transfected the FDCP-Mix A4 cells with a retroviral vector containing this alpha subunit. The ectopic expression of the IL-5 receptor alpha subunit in the FDCP-Mix cells did not increase the observed eosinophilic development but did stimulate survival and proliferation of the transfected cells when IL-5 was added. IL-5 thus acts like IL-3 in these cells, promoting proliferation and survival. The results suggest that IL-5, whilst having a capacity to promote proliferation, does not influence eosinophilic lineage commitment in these multipotent cells. The results further argue that the observed lineage specificity of IL-5 is probably due to factors in addition to the restricted expression of the IL-5 receptor alpha subunit.

Perception of synthetic /ba/-/wa/ speech continuum by budgerigars (Melopsittacus undulatus)

Other than humans, extensive vocal learning has only been widely demonstrated in birds. Moreover, there are only a handful of avian species that are known to be good mimics of human speech. One such species is the budgerigar (Melopsittacus undulatus), which is a popular mimic of human speech and learns new vocalizations throughout adult life. Using operant conditioning procedures with a repeating background task, we tested budgerigars on the discrimination of tokens from two synthetic /ba/-/wa/ speech continua that differed in syllable, but not transition, duration. Budgerigars showed a significant improvement in discrimination performance on both continua near the phonetic boundary for humans. Budgerigars also showed a shift in the location of the phonetic boundary with a change in syllable length, similar to what has been described for humans and other primates. These results on a nonmammalian species provide support for the operation of a general, nonphonetic, auditory process as one mechanism which can lead to the well-known stimulus-length effect in humans.

A new function for the LDL receptor: transcytosis of LDL across the blood-brain barrier

Lipoprotein transport across the blood-brain barrier (BBB) is of critical importance for the delivery of essential lipids to the brain cells. The occurrence of a low density lipoprotein (LDL) receptor on the BBB has recently been demonstrated. To examine further the function of this receptor, we have shown using an in vitro model of the BBB, that in contrast to acetylated LDL, which does not cross the BBB, LDL is specifically transcytosed across the monolayer. The C7 monoclonal antibody, known to interact with the LDL receptor-binding domain, totally blocked the transcytosis of LDL, suggesting that the transcytosis is mediated by the receptor. Furthermore, we have shown that cholesterol-depleted astrocytes upregulate the expression of the LDL receptor at the BBB. Under these conditions, we observed that the LDL transcytosis parallels the increase in the LDL receptor, indicating once more that the LDL is transcytosed by a receptor-mediated mechanism. The nondegradation of the LDL during the transcytosis indicates that the transcytotic pathway in brain capillary endothelial cells is different from the LDL receptor classical pathway. The switch between a recycling receptor to a transcytotic receptor cannot be explained by a modification of the internalization signals of the cytoplasmic domain of the receptor, since we have shown that LDL receptor messengers in growing brain capillary ECs (recycling LDL receptor) or differentiated cells (transcytotic receptor) are 100% identical, but we cannot exclude posttranslational modifications of the cytoplasmic domain, as demonstrated for the polymeric immunoglobulin receptor. Preliminary studies suggest that caveolae are likely to be involved in the potential transport of LDL from the blood to the brain.

Role of enterobactin and intracellular iron in cell lethality during near-UV irradiation in Escherichia coli

In Escherichia coli, fur mutants that constitutively express their native iron chelating agent, enterobactin, are significantly more sensitive to near-UV radiation (NUV) than wild type, An entA mutant, which is incapable of synthesizing enterobactin, is equal to wild type in resistance to NUV irradiation. However, the addition of Fe+3 enterobactin but not AI+3 enterobactin to entA cell suspensions just prior to irradiation results in an increased sensitivity to NUV irradiation. A fes mutant, which is unable to reduce and release iron from enterobactin, is significantly more sensitive to NUV irradiation than wild type. The addition of nontoxic levels of H2O2 (5 microM) just prior to irradiation significantly increases sensitivity of both fur and fes mutants. These results suggest that one mechanism by which NUV irradiation leads to cell lethality is by creating a transient iron overload, producing very favorable conditions for the production of highly deleterious free radicals through a variety of mechanisms that lead to oxidative stress and DNA damage including lethal and mutagenic lesions. These results are consistent with the hypothesis that enterobactin is an endogenous chromophore for NUV and contributes to cell lethality via the destruction of its ligand, releasing Fe+2 into the cytoplasm to catalyze the production of highly reactive hydroxyl radicals and other toxic oxygen species via the Haber-Weiss reaction.

Macrophage inflammatory protein-1 alpha receptors are present on cells enriched for CD34 expression from patients with chronic myeloid leukemia

The response of normal and chronic myeloid leukemia (CML), CD34+ cells to human macrophage inflammatory protein-1 alpha (MIP-1 alpha or LD78) was assessed. In tritiated thymidine incorporation assays, stem cell factor plus granulocyte-macrophage colony-stimulating factor stimulated thymidine incorporation in normal CD34+ cells was reduced to 72% of control values in the presence of MIP-1 alpha, whereas incorporation by CML CD34+ cells exposed to the same factors was not altered. In clonogenic assays, the presence of MIP-1 alpha gave a level of colony formation that was 71% of control values for normal progenitor cells, whereas for CML CD34+ cells colony formation was enhanced by 25%. These results suggest that, in vitro, CML progenitor cells are relatively refractory to the growth inhibitory effects of MIP-1 alpha. Using flow cytometry, the specific binding of a biotinylated human MIP-1 alpha/avidin fluorescein (FITC) conjugate to normal and CML mononuclear and CD34+ cell populations was quantified. The data indicate that (for both normal and CML CD34+ cells) there was a single population of cells that express cell surface receptors for MIP-1 alpha and this receptor expression was independent of cell cycle status. CML progenitor cells may be refractory to the effects of MIP-1 alpha as a result of events downstream from receptor expression.

Expression of lactoferrin receptors is increased in the mesencephalon of patients with Parkinson disease

The degeneration of nigral dopaminergic neurons in Parkinson disease is believed to be associated with oxidative stress. Since iron levels are increased in the substantia nigra of parkinsonian patients and this metal catalyzes the formation of free radicals, it may be involved in the mechanisms of nerve cell death. The cause of nigral iron increase is not understood. Iron acquisition by neurons may occur from iron-transferrin complexes with a direct interaction with specific membrane receptors, but recent results have shown a low density of transferrin receptors in the substantia nigra. To investigate whether neuronal death in Parkinson disease may be associated with changes in a pathway supplementary to that of transferrin, lactoferrin (lactotransferrin) receptor expression was studied in the mesencephalon. In this report we present evidence from immunohistochemical staining of postmortem human brain tissue that lactoferrin receptors are localized on neurons (perikarya, dendrites, axons), cerebral microvasculature, and, in some cases, glial cells. In parkinsonian patients, lactoferrin receptor immunoreactivity on neurons and microvessels was increased and more pronounced in those regions of the mesencephalon where the loss of dopaminergic neurons is severe. Moreover, in the substantia nigra, the intensity of immunoreactivity on neurons and microvessels was higher for patients with higher nigral dopaminergic loss. These data suggest that lactoferrin receptors on vulnerable neurons may increase intraneuronal iron levels and contribute to the degeneration of nigral dopaminergic neurons in Parkinson disease.

Rat mammary-gland transferrin: nucleotide sequence, phylogenetic analysis and glycan structure

The complete cDNA for rat mammary-gland transferrin (Tf) has been sequenced and also the native protein isolated from milk in order to analyse the structure of the main glycan variants present. A lactating-rat mammary-gland cDNA library in lambda gt10 was screened with a partial cDNA copy of rat liver Tf and subsequently rescreened with 5' fragments of the longest clones. This produced a 2275 bp insert coding for an open reading frame of 695 amino acid residues. This includes a 19-amino acid signal sequence and the mature protein containing 676 amino acids and one N-glycosylation site in the C-terminal domain at residue 490. Phylogenetic analysis was carried out using 14 translated Tf nucleotide sequences, and the derived evolutionary tree shows that at least three gene duplication events have occurred during Tf evolution, one of which generated the N- and C-terminal domains and occurred before separation of arthropods and chordates. The two halves of human melanotransferrin are more similar to each other than to any other sequence, which contrasts with the pattern shown by the remaining sequences. Native rat milk Tf is separated into four bands on native PAGE that differ only in their sialic acid content: one biantennary glycan is present containing either no sialic acid residues or up to three. The complete structures of the two major variants were determined by methylation, m.s. and 400 MHz 1H-n.m.r. spectroscopy. They contain either one or two neuraminic acid residues (alpha 2-->6)-linked to galactose in conventional biantennary N-acetyl-lactosamine-type glycans. Most contain fucose (alpha 1-->6)-linked to the terminal non-reducing N-acetylglucosamine.

Human eosinophils express a receptor for secretory component. Role in secretory IgA-dependent activation

The existence of a functional receptor for secretory component (SC) on the eosinophil membrane might explain the preferential degranulation induced by secretory IgA (sIgA) when compared to serum IgA. Indeed, flow cytometry analysis revealed that purified human SC could bind to a subpopulation (4-59%) of blood eosinophils purified from 19 patients with eosinophilia. Binding of radiolabeled human SC could be competitively inhibited using unlabeled SC or secretory IgA but not with serum IgA or IgG. Immunoprecipitation and immunosorbent chromatography using human SC revealed the presence of a major component at 15 kDa in eosinophil extracts as well as in culture supernatants but not in neutrophils. The 15-kDa protein eluted from the human SC immunosorbent was able to bind to SC or to sIgA but not to serum IgA. Eosinophils preincubated with human SC or sIgA released eosinophil cationic protein (ECP) and eosinophil peroxidase (EPO) after addition of anti-SC or anti-IgA monoclonal antibody as respective cross-linking reagents. These results indicated that binding of free or complexed SC to human eosinophils could induce eosinophil degranulation. Furthermore, the dose-dependent inhibition by SC of mediator release induced by sIgA but not by serum IgA, suggested that the receptor for SC could be involved in the preferential degranulation mediated by sIgA. These results indicate a novel pathway of eosinophil activation and its potential involvement in mucosal immunity, particularly in inflammatory diseases associated with infiltration of eosinophils and the enhanced production of sIgA.

Interleukin-2 in neoadjuvant therapy potentiates inhibitory activity of 5-fluorouracil and interferon in experimental liver metastases

Our previous studies showed that interferon (IFN) used in combination with 5-fluorouracil (5-FU) was effective in inhibiting colorectal tumor cell metastases to the liver in nude mice. Furthermore, IFN was also effective in neoadjuvant therapy and allowed the combination treatment (5-FU + IFN) to be delayed for 2-3 weeks following i.s. injections of tumor cells. In this study, we have examined the potential of interleukin-2 (IL-2) to substitute for IFN in neoadjuvant therapy. IL-2 was found to be equally effective, if not superior, to IFN as a neoadjuvant in inhibiting liver and lung metastases with 5-FU + IFN. Moreover, the effect of IL-2 was demonstrable even after 1 week, whereas IFN did not have an effect until 2 weeks of neoadjuvant dosing. These studies demonstrate IL-2 to be more effective than IFN as an immunomodulatory agent in combination with 5-FU + IFN for the inhibition of liver metastases in nude mice.

Expression of the lactotransferrin receptor during the differentiation process of the megakaryocyte Dami cell line

In order to determine whether the human lactotransferrin receptor recently described on platelets was also present on hematopoietic precursors, we investigated its presence and characteristics on the megakaryocytic Dami cell line. The reversible binding of human 5-(([2-(carbo(hydrazino)methyl]thio)acetyl)aminofluorescein-labele d lactotransferrin showed that such a receptor was only present on the subpopulation of the largest cells. The increase in numbers of large cells during culture was paralleled by a concurrent increase in lactotransferrin receptor positive cells. Scatchard analysis of the binding of [125I]-labeled lactotransferrin showed that a single affinity class of binding site was present (Kd = 446 +/- 40 nM) and that there were 52 +/- 3 x 10(5) sites per cell. The mouse monoclonal antibody DP5B3G10, specific for the human lactotransferrin receptor, allowed its characterization as a 105 kDa protein on Western blots. The same monoclonal antibody was used to separate the small and large cell subpopulations of Dami cells by panning. Separate culture of the small cells showed that the receptor appeared prior to and independent from endomitosis. In contrast, GPIb was expressed only by large megakaryocytes. The use of conditioned medium from cultures of whole Dami cell populations indicated that a soluble factor is involved in differentiation, but not in the appearance of the lactotransferrin receptor.

Characterization of two kinds of lactotransferrin (lactoferrin) receptors on different target cells

Lactotransferrin (Lf), an iron-binding glycoprotein present as a major component in the specific granules of human neutrophilic granulocytes is released in the blood during the acute phase of infection and participates in the regulation of the host-defence mechanisms. Our previous observations (Mazurier et al., 1989) showing i) that the activation by PHA of T-lymphocytes induces the appearance at the cell surface of Lf-receptors which are absent from the membrane of resting lymphocytes and ii) that Lf becomes a growth factor for the activated lymphocytes, led us to undertake a series of researches on the presence of Lf receptors at the surface of different blood cells. Characterization of Lf receptors was performed by flow cytofluorimetry using either Lf labelled on its glycan moiety with fluorescein or purified anti-lymphocyte Lf receptor antibodies. High affinity receptors for Lf were characterized only at the surface of human activated lymphocytes and of non-activated platelets. These two receptors possess common physicochemical properties and antigenic epitopes. Low affinity receptors for Lf were characterized on monocytes, eosinophils and neutrophils. These receptors are immunologically different from those found on activated lymphocytes and on non-activated platelets. Cell-lines of human lymphocyte T and megakaryocyte possess lactotransferrin receptors whose properties are similar to those found on peripheral blood cells. The soluble form of the receptor identified in the lymphocytes T culture medium possesses a molecular mass close to that of the membrane receptor suggesting that the cytoplasmic tail of the receptor should be very short.

Transcriptional induction of beta-galactoside alpha-2,6-sialyltransferase in rat fibroblast by dexamethasone

The beta-galactoside alpha-2,6-sialyltransferase activity of Fisher rat fibroblasts is enhanced by dexamethasone while the activity of the beta-galactoside alpha-2,3-sialyltransferase remains unchanged. This glucocorticoid-dependent activation can be inhibited by the antagonist RU 38,486 and results from an elevated transcription rate of the 4.7-kb mRNA previously characterized in rat fibroblasts, distinct from the 4.3-kb liver-restricted mRNA. As shown by the binding of radiolabelled Sambucus nigra agglutinin, this activation leads to an increase of NeuNAc(alpha 2-6)Gal sequences on glycoproteins isolated from the dexamethasone-treated cells.

Molecular cloning of the major cell surface heparan sulfate proteoglycan from rat liver

We have used an antiserum raised against a purified heparan sulfate proteoglycan (HSPG) preparation isolated from rat liver to screen a lambda gt11 expression library and have obtained overlapping cDNA clones that contain the full-length coding sequence of an HSPG core protein capable of spanning the plasma membrane. The open reading frame of the rat cDNA encodes a protein of 211 amino acids. The predicted protein sequence (23 kDa) has a high degree of homology with the published partial sequence of the human lung fibroblast HSPG, fibroglycan. The deduced protein sequence contains a 24-amino acid transmembrane domain and a 33-amino acid cytoplasmic domain, both of which are identical with the corresponding regions of human fibroglycan and are highly homologous to the human, hamster, and mouse epithelial HSPG, syndecan. The putative ectodomain, which has 85% homology to fibroglycan, contains three possible glycosaminoglycan attachment sites that may be occupied by heparan sulfate chains. The major 49-kDa core protein in the liver HSPG preparation was found to be reactive to an antibody that specifically recognizes the cytoplasmic domain of fibroglycan. We have used the full-length cDNA clone to analyze the expression of this transmembrane core protein gene in whole tissues and several epithelial and fibroblastoid cell lines. It hybridizes to three mRNA species in all cell and tissue types examined, but in liver, isolated hepatocytes, and kidney, an additional 0.8-kilobase mRNA was detected. The three common messages arise from differential use of alternative polyadenylation sites, whereas the fourth tissue-restricted RNA species represents a related gene transcript. The rat equivalent of human fibroglycan therefore appears to be the major transmembrane proteoglycan in liver, and its widespread expression in many diverse tissues and cells suggests that it plays an important role in cellular interactions.

Psychiatric nursing education in Nebraska: 1989-1990

The academic and clinical content of psychiatric nursing curricula in the registered nurse basic educational programs in Nebraska for academic year 1989-1990 was explored by the Nebraska Sub-group of the Nursing Curriculum and Training Task Force of the National Alliance for the Mentally Ill. The review includes literature regarding the history, development, and future trends of psychiatric nursing; factors affecting nursing student attitudes toward psychiatric patients; basic content included in psychiatric and psychosocial nursing curricula; and concepts essential in working with the seriously, persistently mentally ill. Contrary to current trends in the United States, all Nebraska schools of nursing have a generic psychiatric nursing course taught by clinical specialists in psychiatric-mental health nursing. Hands-on clinical time spent with patients with psychiatric diagnoses as well as those with psychosocial needs varies from 84 to 200 hr per semester. Not all students are exposed to patients with severe and persistent mental illness. Fewer than 5% of Nebraska graduates choose psychiatric nursing as their area of practice. The authors express grave concern for the future of psychiatric nursing education. Implications for curriculum revision and replication studies are suggested.

Surface resorption following two forms of rapid maxillary expansion

Rapid maxillary expansion (RME) is a useful orthodontic technique for correction of posterior cross-bite of skeletal origin. The aim of the present study was to compare the frequency and nature of root resorption in premolars subjected to RME by means of either a tissue-borne, fixed split acrylic (Haas) palatal expansion applicance, or an all-wire framework appliance. Another factor examined was the relationship between the pattern of resorption and the duration of the retention period. RME was performed on five patients using the fixed split acrylic appliance and on four patients with the all-wire framework appliance. Following the transverse expansion, two upper and two lower premolars were extracted and processed for histological examination. Root resorption was found mainly on the buccal surfaces of all maxillary premolars. The resorption lacunae covered more of the root surface in premolars treated with an all-wire framework appliance compared to premolars treated with the acrylic expansion plate. The largest resorption areas were found on teeth extracted shortly after the expansion period and the smallest on premolars retained for a relatively longer period. Mandibular premolars showed neither buccal nor lingual resorptions. It was concluded that maximum anchorage of the expansion device, using the tissue-borne acrylic appliance, seems preferable in order to minimize the incidence of buccal surface root resorption. A longer post-treatment observation time is needed in order to draw more specific conclusions regarding the healing process of the damaged root surface.

Molecular cloning and sequence analysis of bovine lactotransferrin

The screening of a bovine submaxillary gland cDNA library yielded 25 clones coding for bovine lactotransferrin. The nucleotide sequence of the longest insert contained a protein-coding region of 2115 nucleotides and a 3' non-coding region of 194 nucleotides followed by a poly(A) tract of about 55 nucleotides. The predicted peptide sequence included a 16-amino-acid signal sequence upstream of the first amino acid of the native protein. The identity of the clone was confirmed by matching the amino acid sequence predicted from the cDNA with the N-terminal and tryptic peptide sequences derived from purified bovine milk lactotransferrin, and also by similarity with human and murine lactotransferrins. The cDNA described corresponds to a 705-amino-acid-long preprotein that lacks the start methionine. The sequence of the secreted protein is 689 amino acids long and contains five potential glycosylation sites. Bovine lactotransferrin is 69% and 64% identical to human and murine lactotransferrins, respectively.

Pathophysiological and therapeutic aspects of dentoalveolar resorption

Both physiological and pathological forms of bone and tooth resorption are seen in the dentoalveolar complex, and much of the non-restorative component of a clinician's work is occupied by problems related to loss of bone or dentine. Bone resorption is also a feature of many systemic diseases, some of which can affect the alveolar bone. The aim of this report is to summarize some recent work in which the dentoalveolar complex has been used as a model system to study physiological, pathological and therapeutic aspects of resorption of bone and dentine.

Chemical toxicology for the coroner

Toxicology results from all 302 coroners' cases referred to the supraregional unit at Beaumont Hospital over the one year period December 1987 to November 1988 are detailed. Clinical details were provided in 69.5% and formed the basis for the formation of four groups; road traffic accidents, suicides, possible suicides and possible carbon monoxide poisonings. All tests reported were instigated by the referring pathologist on behalf of the coroner. Alcohol was measured in all except 11 patients and a positive result was found in 44%. Drug screens were performed in 68.5% of cases with a positive finding in 30%. At least one positive result was found in 61.9% of the total. In the 60.4% of 53 road accident victims where alcohol was found, the median value was 117 mg/dl. COHb was measured in 23 cases and the median saturation was 45%. There were 12 suicides and agents found included paraquat, CO, cyanide, pancuronium bromide, and amitriptyline. Alcohol levels greater than 120 mg/dl were present in seven. In the 22 cases of suspected suicide, 77.3% were positive for drugs and more than one substance was found in 45.4%.

Development of elastic fibres in the upper urinary tract

The development of elastic fibres in the upper urinary tract was studied in 31 fetuses ranging in ovulatory age from 10 to 24 weeks using special staining techniques for elastic fibres. The number, orientation and distribution of elastic fibres are described and correlated with age, ureteric level, and fetal weight. Significantly, before 10 weeks, elastic fibres were few in number, poorly developed, and randomly arranged. After 12 weeks, these fibres became more numerous at each level of the urinary tract, and were seen to develop specific orientation. The findings are described and potential clinical implications are discussed.

[Calcitonin as an alternative treatment for root resorption]

Inflammatory root resorption is a common finding following trauma and will cause eventual destruction of the tooth root if left untreated. This study examined the effects of intrapulpal application of calcitonin, a hormone known to inhibit osteoclastic bone resorption, on experimental inflammatory root resorption induced in monkeys. Results were histologically evaluated using a morphometric technique and revealed that calcitonin was an effective medicament for the treatment of inflammatory root resorption. It was concluded that this hormone could be a useful therapeutic adjunct in difficult cases of external root resorption.

Spreading of dentinoclasts on various substrata in vitro

An in vitro system for isolated dentinoclasts is described in which clastic cells which are not contemporaneously engaged in resorption are gently rinsed from the surface of actively resorbing root dentin. Dentinoclasts were cultured on a variety of hard tissue constituents in order to investigate the effects of substratum composition on the expression of resorbing structures by these cells, and examined with scanning electron microscopy. Results revealed that dentinoclasts express both ruffled borders and clear zones only when cultured on coverslips coated with both collagen and hydroxyapatite. Hydroxyapatite alone induced only the formation of a clear zone. Failure to express either clear zones or ruffled borders by cells cultured on collagen-coated coverslips was interpreted to reveal that collagen itself is not capable of, but requires the mineral component of hard tissue for, producing morphologic resorbing structures in clastic cells.

Coated pits and vesicles in the osteoclast

The osteoclast is a cell with a phagocytic ability not dissimilar to the macrophage. Nevertheless, the mechanisms by which it resorbs bone are poorly understood. The aim of this study was to examine the distribution of coated membrane structures in the osteoclast in order to gain further information about endocytosis in this cell. Osteoclasts around the developing tooth germs of young rats were examined using transmission electron microscopy, and immunocytochemistry. Results showed that previously described coated membrane structures within the ruffled border do not appear to be associated with coated pits or vesicles. Coated pits were, however, evident on the dorsal and lateral surfaces of the cell, particularly opposite the clear zone areas. Immunogold staining for clathrin confirmed that coated pits and vesicles are absent within both the clear zone and ruffled border areas, but present on the lateral and dorsal surfaces of the actively resorbing cell. It is suggested that clathrin-associated receptor-mediated endocytosis occurs along the lateral and dorsal surfaces of the osteoclast for the uptake of nutrients and macromolecules, while endocytosis of bone mineral by the ruffled border is mediated by a non-clathrin associated coated membrane structure.

The effect of an antibiotic/corticosteroid paste on inflammatory root resorption in vivo

Progressive external inflammatory root resorption, a result of persistent inflammation within the periodontal membrane, will cause eventual destruction of the tooth root if the inflammation is not eradicated. This study examined the effects of an antibiotic/corticosteroid paste on experimental inflammatory resorption induced in monkeys in vivo. Histologic evaluation of results with the use of a morphometric technique revealed that the paste eliminated inflammatory root resorption and had no damaging effects upon the periodontal membrane. It was concluded that this antibiotic/corticosteroid combination is an effective medication for use in the treatment of progressive root resorption in traumatically injured teeth.

Resorbing potential of different connective tissue types

Pieces of dentin were implanted into five different connective tissues in rats and examined with scanning electron microscopy after observation periods of up to 2 weeks. Dentin-oclast-like cells, apparently involved in resorption of the implants, were only seen associated with periosteum and periodontal membrane. These findings indicate that the resorbing potential of connective tissues is related to their ability to induce bone formation.

Surgicel: macrophage processing of the fibrous component

Previous reports have demonstrated that Surgicel, a local haemostatic agent, is absorbed from implantation sites. In an earlier study, it was shown that the material consists of a uronic acid component and a fibrous residue. A chemically quantified loss of the uronic acid component within 18 h of implantation was demonstrated. The aim of the present study was to examine the fate of the fibrous residue in rat tissues, using both light and electron microscopy. Results indicated that this fibrous component is phagocytosed by macrophages at the site of implantation. A model for the clearance of Surgicel from tissue implantation sites is presented.

Induction of a protective immune IgE response in rats by injection of defined antigens of schistosomulum-released products: immunochemical properties of the target antigens

Brown Norway rats were injected without adjuvant with the soluble products liberated in a 16-hour culture by schistosomula (schistosomula-released products, SRP-A). A strong cytotoxic and protective IgE response was elicited, mainly directed against 22- and 26-kilodalton (kDa) SRP-A molecules. In the present study, we have attempted to characterize further those molecules. Metaperiodate denaturing treatment of the SRP-A glycans before injection into rats did not modify the immunogenicity of the SRP-A antigens. Results obtained by lectin affinity suggested that the 22- and 26-kDa molecules were glycoconjugates binding to ConA. Preparative sodium dodecylsulfate electrophoresis has allowed the separation of enriched fractions of 22- and 26-kDa molecules which have been injected separately into rats. The corresponding sera were tested in antibody-dependent cell cytotoxicity and displayed a significant cytotoxic IgE response (65 and 53%, respectively) towards the larvae. These results lend further support to the view that the 22- and 26-kDa antigens are the major targets of the protective IgE response and thus appear as potentially protective antigens.